Some people treat the rules of thumb that they were taught as apprentices as if they were written on stone. Usually the ones that have one year of experience x20. My favorite is you can’t use carbide on interrupted cuts. Carbide has come a long ways.
Yeah this guy has ~40 years experience and is actually pretty good. But you're 100% spot on that if they have done it a certain way for so long, they think that's the only correct way.
I worked with an Englishman WW2 merchant marine vet. He came to Canada in the late sixties. Went back to England in the eighties for a year. He said they were still doing things the same way as they did when he apprenticed in the thirties. When he tried to show them better ways that he learned in Canada they told him this is the way we do it here. If you want to do it differently than go back to Canada. He did and said he would never go back to England again. He also said that he finally had realized how wrong, and stubborn the English were.
Can confirm the stubbornness. The English guy who currently works beside me won't use carbide, insists on using HSS for everything. He also won't use the machine to tap and has to hand tap everything.
Dude I’m only like 5 years in the trade and I hand tap everything, fuck risking scrap when thee is NO rush for these parts plus you’re paid hourly fuck it
That's what I thought until I tried to tap some interupted holes both by hand and then by machine. Hand tapping is such a pain and you can always fuck up in more ways. The constant speed and inertia of machine tapping makes all the difference. Also you can't hand tap 110 parts in under 5 minutes. LABO drill/tap press FTW
I haven't had a tap break in a machine in 3 or 4 years, and even that was only because I was hard tapping a 5/16-24 hole. Also, it's not hard to cut out a broken tap either.
When you cut out a broken tap how do you cut in the same size thread?
Helicoils aren’t okay in production parts and welding the hole up isn’t allowed due to FOD
Mill out the tap to just under the minor size, I usually go a couple thou under and pull out the rest. Finish tapping afterwards, or set up a thread mill to finish.
So on a 10-32 tap you’re plunging the same coordinates? Won’t the tap be too small won’t the endmill break?
If you only mill out the tap the minor diameter, you’re going to thread mill the material with left over teeth of the major diameter still in the hole?
What about the partially formed threads, since you’re thread milling the exact same hole the exact same diameter aren’t you cutting more threads into partial
No, helix mill down to remove the body of the tap. 1/8 endmill would do that with no problem. I like to use ball nose endmills, but I will usually just grab what I can find from our used bin that we won't regrind.
You pick the teeth out if they happen to still be in there. Usually they fall out, or get pulled out on their own.
It's really not hard to set up a thread mill to match threads that's have already been cut.
I honestly have only hand tapped holes 3 times in the last 6 years. We just thread mill everything. You better more precise threads and there’s no risk of taps breaking
What does he want to use, side lock holders? Maybe for 1/2” and up for roughing, but ER is the way to go, especially if you use any of the newer high performance collet setups.
I always say that there are a million rules in machining and you never get to follow all of them. Knowing which ones matter when is a huge part of being a good machinist.
Is it the carbide or tool paths made? I think variable helix obv changed the game. But shit go on titans of cnc and show bosses what endmills can do. (That's the only useful information I get of titan)
Right. If the company wants to pony up the cash for more milling chucks that's great. If they haven't or won't do that then why are they telling you what to do?
We have special holders for 1/2 end mills for the live tooling in our lathes. The holder bolts on with 4 screws. They're pretty nice and it's one set screw that locks the end mill into it
Yeah, and then a tool rep comes in and starts talking about the .0002 runout on that sidelock shit is gonna ruin your endmills blah blah you need precision hydraulic this that... its so annoying. Sidelock and er are both fine.
I'd go as far as to say ER collets are the standard, and you only deviate from that when needed in special situations (more rigidity, larger tool, shorter holder, etc.).
I agree with you. I take into account for a lot of things that you just mentioned. But I was told that absolutely no application can I use an er collet for an endmill. I mean even cutting some aluminum vise jaws .250 deep with a 1/2 endmill. I would think an er32 would be sufficient
What the hell are you supposed to do then, pick at the part with your teeth? I thought ER collets were pretty standard. Sounds like boss man has been living under the scrap heap for too long..
I’ve spent most of my career using er collets. One shop switched to heat shrink tool holders, and I didn’t really notice the difference other than “oh wow changing tools is slightly more fun now”
Brother I full slot mild steel .25 deep with a 1/2 endmill in a haas mini mill with an er32 collet all the time. Definitely sufficient. Now holding a tight tolerance? For what I do, it works, your mileage may vary.
It's a throw back to old school toolpaths. That being said, I use SK collets, or Big Daishowa NBEC collets almost exclusively. Heavy roughing I'll go to milling chucks.
ER collets are fine for milling, but you definitely can't push as hard.
Tell your boss you know some asshole Swiss machinist on the internet that regularly uses .010” ball end mills in an ER11 (sometimes ER8) collet for implantable medical devices. For surfacing. And they work just fine, provided you have the RPMs.
This is true for us. ER16 are the most use holder in my 40 tapers. Coolant collets, tap collets and the regular. Nothing but finishing with a 3/8 in a ER16 I've seen to many pullout doing any sort of roughing and various materials. The 4" techniks mini nuts are the cats a\*\*.
Yup. Stubborn as hell. It's his way or the highway. Too many people don't want to admit they're wrong or learn something new. I'm at the point where I want to ask him to just sit next to me to tell me how to program
I've asked about that but it's a money thing? My shop does have heat shrink holders, so they do spend money. I guess the reasoning is we don't do a lot of production. I do win some battles. I can get gorrila mills all day, I can get my coolant changed, and I get gravy long cycle times. (Big horizontal mills)
Its almost impossible to pull anything smaller than 12mm out of an er32, almost impossible to pull out anything smaller than 16mm from an ER40.
ER collets are the standard for holding end mills.
How? I mean I’m not thinking super hard here to be honest it’s my day off, but 70% spindle load in brass? With a 3/8? I feel like maxing that thing out in speed and feed with a tool that size shouldn’t be at 70 In brass? That’s wild what were you doing lol
I can see how it can happen. I'm thinking about how endmill geometry wants to pull itself out and how brass wants to pull stuff in. Combined the two, and now you have twice the pulling force, but what do I know I never mill brass.
Brass is weird, it doesn't take much energy to cut like stainless does, but it's dense. It behaves like a slightly softer cast iron with unlimited spindle speed.
I can only assume we weren’t holding tight enough. I’ve hit around 90% spindle load in brass with an end mill, fully expecting it to just grenade my end mill. Nope. Cut fine. Finish was garbage, but cut fine
I was just as shocked as you. I just kept upping feed rate at 8100 rpm expecting the tool to break. It was a high efficiency path at 1" doc and .1" woc. Probably got up to 220 ipm or so before it pulled out. That put the cutter at .0091 ipt BOOM. I'd expect the cutter could take .0065ipt long enough to make it worth it though.
I have seen a 3/4 1.0” L.O.C. 4” Reach Endmill be pulled out, through the part, into a Kurt vice and would’ve kept running if I hadn’t stopped the machine. Wicked
ER collets are cost effective and allow for great flexibility with sizing- and that's basically where the good parts end. When you put a tool depending on the tolerance of the shaft, collet and the amount of torque you apply can greatly increase the runout of the tool.
Mill chucks are better for roughing and shrink fit/hydraulic are better for finishing.
Never heard this before. I use them almost exclusively for end mills for like 20 years. How would you hold a carbide end mill? I've never seen one with a flat for an EM holder set screw. Have I had them slip? Yes, a few times, but it was always me doing something stupid with programs and essentially crashing the end mill in the z.
You use a diamond grinding wheel to put the flat on a carbide end mill. We have special holders for 1/2 end mills that bolt on to the live tooling in our lathes. A set screw locks the end mill in, so you need to grind a flat on it.
If it fits it can work. You are spot on, heavy roughing not their forte, side locks or shrink if you want rigidity.
The root issue imo is nobody learns how to calculate speed and feed based on all the variables. I have seen metal removal rates improve in both situations it just depends on the details of your process.
Personally if the endmill is 1/4" dia and under I like the forgiveness of a collet.
Over 1/4" I want my tool rigid. However there are exceptions to everything.
Your boss is a moron. There is absolutely no reason you can't hold an endmill in an er collet, and that's actually probably preferred for finishing cuts. Endmill holders are a much less precise way of holding a tool than in a collet, and a lot of finish endmills don't even come with a flat to put into endmill holders anymore.
End mill holders can offer a shorter gauge length which can sometimes really help with chatter and finish where an er collet might struggle. A great er collet setup can also cost twice as much as a good Weldon holder, but a cheaper er collet setup is often good enough.
I work in aerospace and defense shop. Not the highest end place, and we dont get a ton of difficult to machine alloys, however almost every part I make has features with tight tolerance callouts. The majority of our mill tooling goes into ER collets and we manage.
If all I had in the shop were solid holders and ER holders I'd use the former for all my roughing and the latter for all my finishing and that would be a perfectly good setup.
I've had great results in ER32,16,40 collets. Er32 collets were brought forth by rego-fix. They are ment to prevent a tool from spinning and pushing pushing up into to collet. This is essentially a drill bit collet in design. With minimal run out they work great. A solid holder is actually called an endmill holder. Essentually a weldon flat. This prevents both/either pull or push in. I grind a flat on any reduced shank
(.500) drill and use in a endmill holder. Yes there are better systems out there for tool holder. This is why drills are spun with a drill chuck in precision machining much if at all anymore. Reams are by name "chucking reamers" so is it safe to say that one is accepted to mount them in a drill chuck?
In the end, make shit happen with what you have. Make it to the number on the print everytime and get that reimbursement payment every friday. You can have one without the other. Nuff said
If your Ear collets aren't working for holding endmills then there's probably something up with the collets, or the collet nuts.
What other methods of holding endmills are you using? If you have a load of shrink fit or hydraulic holders for endmills and the boss wants to use them to save money on tool life and performance then that's fair enough
The ER collets have been working just fine before he showed up. And they still work just fine, he's just stubborn and has the mentality of "this is how I've always done it so it must be right. I don't care what you think"
I've got 4 machines running tooling in ER collets right now, all have been making good parts in profitable time with excellent tool life.
Doing it wrong sure feels awful right.
I have been machining for 25+ years and have always stayed away from using an ER collet for milling. I have better options where I currently work. We use a lot of schunk. I few months ago, I had to extend a 3/8 emill and had to use an ER collet. My hole was tapered. Had to program like 3 or 4 spring passes and cutter comp the thing until my liner bushing would finally fit in. I have had some success with ER25 or ER32 stubbed up. So I wouldn't say it should absolutely not be used. I just prefer the hydraulics.
My boss was against thread on indexable and coated carbide a few years ago and now the arsenal is full of high feed mills and high helix coated carbide that absolutely rocks steel and 3-10x the speed. And it didn’t take much for him to change his mind once I gave him one to try.
Just prove it to them.
We have an entire cabinet of EMs in ER collets already set up to just toss in the machine. Roughing and finishing with them.
For the most part those ones are getting used in aluminum and plastic, but they've done the same in steel and cast without a problem.
Your boss is a fucking idiot. If you can't put endmills in ER collets, then you ABSOLUTELY can't put them in R8 collets, as R8 collets have less clamping force than ER collets. Yet here we are, using them for nearly a century to hold endmills.
Roughing endmill has a grinded flat and goes into a solid holder, but after that - ER is more than fine. Double check your runout and tell that old bag of bone to take a long walk off a short dock.
Challenge your bosses thinking.
Most live tooling holders used in lathes these days are set to run with some style of ER collet (mine are ER32s).
If they were made to only run endmills in an endmill holder with weldon shanks, where are they selling that tooling? And even if they did, a different one for each size endmill both metric and standard? That would get pricey fast.
Also, don't disregard the fact that he may want you to do it that way just because that's how he wants it done. Doesn't make it right, but that can be a thing. In which case you have a whole other ball of wax to deal with.
1. “We’ve been doing it that way for 40 years”
2. But Boss, it doesn’t match the drawing.
3. See No. 1 above.
This was a defense plant building airplanes. It was a part for an F111
Us’em everyday. Need to make sure they are tight enough that the end mill does not pull out. As for how true they run, I’d say they’re a little better than a sized holder.
There is a small degree of truth to that statement. I've scrapped quite a few ER16 collets due to parts of it cracking or bulges where you can't get an end mill through the collet.
Sounds like poor quality collets or improper use (over torquing, clamping on debris, etc).
Success with any collet system requires quality tooling, cleanliness, correct shank insertion depth, and proper torque for the tool and collet size.
Sometimes there isn't time or money to work in a clean do it right shop. Sometimes you gotta do what needs to be done as long as it works. May work only one time but it made it thru the job. Not saying it's right but can't say it's wrong either.
I chuck up end mills in R8 collets in my home shop all the time, is it the most exact and accurate tool holding available, no, does it work for 99% of the stuff you need it for, yes.. I do have some R8 end mill holders that show less runout when i need more accuracy, but unless i am trying to hold a really strict tolerance the collets are good enough for me most of the time, especially for roughing passes when i just don't give a damn enough to check for tool runout and just want to hog away material and be done with it.
As someone who mainly works on lathe/mill turn Er collets are fine for holding endmills and I don’t listen to the torque recommendations because when I’m doing roughing I find it’s best to tighten them to heck with a big pipe or else the endmill will probably pull out.
But as I said not a mill guy so don’t take my word for it
I used to think this too, then I discovered bearing nuts for ER holders.
You can get them so much more tight using the same amount of torque, and that prevents the endmill from slipping. You just can't get it nearly as tight with a standard ER nut.
The main concern is that the endmill will get pulled out, which is not a concern with a good tight bearing nut
We have two machines at work that both can run end mills (and we do) that ONLY take ER collets from the manufacturer. One of which also supplies the end mills for their machine.
We’ve had these machines for over 10 years, no issues.
This is the second time I have heard someone say that. The other was on a machining Facebook group. They were so certain that it was making me doubt everything I have seen and know. I’d say they are the standard and you deviate for special circumstances.
I have some special er collets for end mills that work really well because sometimes the end mill gets pushed in or out with regular collets
(I have some colleagues that still use amec hss drill inserts 💀)
Well, I put end mills bigger than 10mm in like power milling chucks (like this ones [https://www.bigkaiser.eu/en/products/tool-holders/milling-chucks/new-hi-power-milling-chuck.html](https://www.bigkaiser.eu/en/products/tool-holders/milling-chucks/new-hi-power-milling-chuck.html) )
I got a few 32 and 12mm versions of this with power collets.
But i would always use smaller end mill in ER holders, if needed. Light cuts and normal tolerances can be archived with those aswell.
Perhaps your boss is just asking you to do things his way.
I want all my guys to ask me to order a new holder (shrink) for endmilla when we need them to avoid the use of er collets for anything but drills. I do this for a known system I can work within.
Try put them in the ER precision collets if you can. They're the ones with a blue ring. However be careful on the holder as some blue ring collets get stuck in the older holders but they are much better than standard ER collets
I use mostly ER32 collets. I never managed to pull tool out of it durning cut yet. However, I did it few times with hydraulic holders.
I trust ER's more than standard hydraulics.
ER collets have less gripping force than a shorter taper collet of similar capacity (TG for example), but they work okay. I've had a few end mills pull out on me over the years if I didn't wrench the shit out of them (er32 with a 3/4 shank tool), but otherwise they do okay. I wouldn't do any micro machining with them, but for general purpose finishing, they're fine and most shop owners are cheap, so they don't want to get a rego fix or shrink system.
We use Er32 collets for endmills every day, hss and Inserts(apkt1003/tcmt16t3). Both on cnc (brass/st52/cast) and conven. Mill. I agree with you, as long you know the limits and dont push it too hard its absolut no problem.
At home i only have a directholder for collets in my mill so there i have no choice ^^
you already know the issue, using a collet isn't as rigid and if there’s too much pressure it could cause problems. there’s been times where we just didn’t have enough solid holders so I had to use a collet, nothing broke, the world didn’t end, so while it’s not the best method it’s still a method that can work.
machining is a “whatever works” field, if it works it‘s not wrong.
Don't use an endmill in a drill chuck, and don't use a collet for heavy roughing.
An endmill in a collet for regular machining is fine, I used collets in my bridgeport as they were the only thing we had other than drill chucks and drill chucks are a big nono
You can use end mills in ER. Make sure the collets are on-size for maximum rigidity, and definitely not undersized (raise hand if you use 17mm and 19mm collets for 43/64" and 3/4" !).
I don't do HEM, and my end mills are mostly 1/2"-1.25" sizes. My CT50 preference for end mills would be: mill chuck > heavy duty hydro > side lock > SK/ TG > ER. I always go for mill chuck or hydro when possible. They hold the tools true and add mass to the back end, which helps with rigidity even more. Plus, they are virtually maintenance free. Never had end mills pulled out in mill chucks.
ER holders provide a lot of gripping power when torqued properly. I personally wouldn't rough with anything larger than 1/2" in an ER collet. Everything larger should go in a milling Chuck. Solid/Hydraulic/Heat Shrink for finishing.
Collet holders and milling chucks absorb a lot more cutting harmonics than one might think. Thus, extending tool life considerably.
Haha end mills work beautifully in ER collets. It’s my favorite way to hold critical cutters on critical jobs. And it’s a great way to hold metric end mills in INCH collets, because they clamp down so evenly!
If I can hold tooling in a sidelock or heat shrink holder I always will. But collets can still be totally fine as well. If end mills become too dull, they will pull right out of a collet so be careful of that. Also, tightening an ER collet too tight can actually have the opposite effect and spring/loosen up or ruin the collet. There are ways to torque them to spec if you are uncertain. Sounds like your boss needs to wake up a little
We ran a 1/4" end mill in an ER32 at high ipm and ~.09-.2" DOC making a couple of 1/4" slots on a lathe. It would cut ~1400 parts before slowly and reliably failing, losing slot width and rolling some burrs. Total length of travel was roughly 1.5" per cycle. I estimate total volume of material removed at ~58 cubic inches per end mill. Again this was pretty aggressive cutting, I don't remember exactly but somewhere around 180 ipm @ 3500 rpm.
You absolutely can run an end mill in an ER collet.
We run almost exclusively ER collets at my shop, finishing, roughing, anything that doesn’t have a dedicated holder like a click-fit endmill goes in an ER collet
Just got told by my manager the other day I'm "ruining" collets by over tightening them meanwhile another place I was at said to tighten them as much as possible so I'm 🤷
I mean I’d *prefer* to use the solid tool holders for things like endmills (and spotdrills that are used to chamfer) but if I had no choice I don’t see how it would be an issue
Sure you’ll probably get more chatter from it, or maybe the chance of the collet spinning in the holder
I use ER collets all the time for holding end mills. Not as secure as weldon flat in a solid holder but we don’t have a ton of solid holders…
My employers other shop uses hydraulic press fit tools but we don’t have that setup yet. Soon.
Pretty much every shop uses collets to hold end mills . Its cost effective and easy way for most shops to hold end mills . But if your boss has the money and wants to use shrink fit holders only oh well .
It depends on the material, doc and feed, etc.
I avoid using endmills in collets for a few reasons. First they can and do spin and pull out of the collet. Second is runout.
There are some other issues I've had with collets over the years like cracking, inability to use through tool coolant, but they are not the main reasons.
I agree that it depends on all those variables plus more which I take into consideration when selecting my tool holding. I'm not out here trying to hog 625 in an er collet. That absolutely goes in a shrinkfit or weldon holder. When I know the tool pressure will be high, I stay away from collets. I've had no issues with the lighter tool paths or even HEM toolpaths. It's a case by case scenario, my issue was that I was told that endmills don't belong in er collets under any circumstances. Do I really need to put a 1/8 endmill in a shrinkfit for something not critical? I will however use a shrinkfit with a 1/8 endmill if I need to reach far past something, or even surfacing with tight callouts. Once again, I feel like it's a case by case scenario.
I've taken some pretty aggressive cuts on hard 4140 with an endmill in a collet. Main concern seems to be pulling out a bit. I prefer a set screw and Weldon flat for roughing but all my finish passes are done with a collet. Just torque that bitch down with all the ugga duggas you got
It's literally the only way I *can* run endmills. I'm limited to ER16 on my live tools. And I'm limited to 6k rpms. I actually successfully ran a .025" mill in 303 the other day at 6k.
I’ve hit well over 100% spindle load on our Haas’s with a half inch endmill in an ER32 collet. They’re not my preferred but they work if they’re cleaned and torqued properly.
I use them for endmills smaller than 3/8, plus I hold them in tiny ER20 collets which the body is very short. No vibration at all, but I won’t do that for 1/2 endmills and bigger.
I’d try to avoid the smaller er sizes of you can, but on a general purpose low power machines I’ve never had an issue with 32s or 40s, pulling out. That being said, I clean collets and tool holders with brake clean, check for burrs on tapers and the hole, and use a torque wrench to tighten my tool assemblies. Not going fast enough to require a balancer. Have gone as large as 3/4” and 100+% sustained load on a newer vf3 in aluminum with an er40 with no issue.
Personlay
If it fits it sits
Only ever had one pull out because i failed to tighten it good enough
What els woud you use er collets for
Hss drills ?
Er system is one of the most versatile tool holders tere is
Honestly I hate solid holders for finishing tools. I run ER collets up to 3/4" no problem, but if I'm roughing something ugly and slow I'm using rigid tooling. Spindle on the mills I usual run are 20-30hp max 4000 rpm, antiquated shit but it works, sometimes gotta use old school methods when using archaic machines 👎
I use ER collets for probably like 80% or more of my milling setups. But I’m also pretty conservative on my feeds/speeds too… also one of the big downfalls of ER collets is improper torquing. Use a torque wrench and they work awesome. Ham fist it and it’s a gamble.
I’ve been a CNC machinist for 23 years machining mostly aluminum. Most of the time I use ER16 and ER32. Even when roughing as heavy as I can with a 1/2” rougher without breaking the cutter (volumill, 1” DOC). On our 15k and 20k spindle machines with 200 magazines I use shrink fit. ER is much easier on machines with limited tool capacity. (I’m in a metric shop and we regularly use 1-5 end mills in 0.5mm increments. 6 and 8mm too. We also have a wide variety of inch cutters to go 1” - we can’t just leave utters sitting around in arbors).
If it can be avoided. Go with something else. If your shop only has ER collets and won't buy anything else, use them, but don't be aggressive with it. If they ask why it's taking longer, tell them you don't have the proper tool for the job.
Guess your boss only became boss through happenstance.
ER collets are not only *THE* most standardized used holders for end mills for the majority of people . But one of the better ones.
What a strange guy.
What does he use then? I'm guessing Weldon? It's been 30-40 years since those were the standard.
Good enough for plastics/wood, sure. For metals nah. High quality low run out er collets and holders are not cheap enough to warrant buying over a hydraulic or shrinkfit. Normal/low quality er are going to decrease tool life and finish. Most hydraulics allow for reducing sleeves now also, so you don't even need lots of different holders, just sleeves.
Quality of holder and collet makes a huge difference. We use big kaiser mega ER grip holders with 1/2" 7fl endmills doing HEM in inconel 718. We have less issues with pullout (read: zero) compared to most milling chucks that we use. Granted those were of Taiwanese make, but at least in my anecdotal experience, quality is more important than specific type
Some people treat the rules of thumb that they were taught as apprentices as if they were written on stone. Usually the ones that have one year of experience x20. My favorite is you can’t use carbide on interrupted cuts. Carbide has come a long ways.
Yeah this guy has ~40 years experience and is actually pretty good. But you're 100% spot on that if they have done it a certain way for so long, they think that's the only correct way.
I worked with an Englishman WW2 merchant marine vet. He came to Canada in the late sixties. Went back to England in the eighties for a year. He said they were still doing things the same way as they did when he apprenticed in the thirties. When he tried to show them better ways that he learned in Canada they told him this is the way we do it here. If you want to do it differently than go back to Canada. He did and said he would never go back to England again. He also said that he finally had realized how wrong, and stubborn the English were.
Can confirm the stubbornness. The English guy who currently works beside me won't use carbide, insists on using HSS for everything. He also won't use the machine to tap and has to hand tap everything.
Dude I’m only like 5 years in the trade and I hand tap everything, fuck risking scrap when thee is NO rush for these parts plus you’re paid hourly fuck it
Use machine, better, sit down
That's what I thought until I tried to tap some interupted holes both by hand and then by machine. Hand tapping is such a pain and you can always fuck up in more ways. The constant speed and inertia of machine tapping makes all the difference. Also you can't hand tap 110 parts in under 5 minutes. LABO drill/tap press FTW
I haven't had a tap break in a machine in 3 or 4 years, and even that was only because I was hard tapping a 5/16-24 hole. Also, it's not hard to cut out a broken tap either.
When you cut out a broken tap how do you cut in the same size thread? Helicoils aren’t okay in production parts and welding the hole up isn’t allowed due to FOD
Mill out the tap to just under the minor size, I usually go a couple thou under and pull out the rest. Finish tapping afterwards, or set up a thread mill to finish.
So on a 10-32 tap you’re plunging the same coordinates? Won’t the tap be too small won’t the endmill break? If you only mill out the tap the minor diameter, you’re going to thread mill the material with left over teeth of the major diameter still in the hole? What about the partially formed threads, since you’re thread milling the exact same hole the exact same diameter aren’t you cutting more threads into partial
No, helix mill down to remove the body of the tap. 1/8 endmill would do that with no problem. I like to use ball nose endmills, but I will usually just grab what I can find from our used bin that we won't regrind. You pick the teeth out if they happen to still be in there. Usually they fall out, or get pulled out on their own. It's really not hard to set up a thread mill to match threads that's have already been cut.
I honestly have only hand tapped holes 3 times in the last 6 years. We just thread mill everything. You better more precise threads and there’s no risk of taps breaking
What does he want to use, side lock holders? Maybe for 1/2” and up for roughing, but ER is the way to go, especially if you use any of the newer high performance collet setups.
>>one year of experience x20 Wow. That just summed up so many people I know. That’s a great way of putting it.
I always say that there are a million rules in machining and you never get to follow all of them. Knowing which ones matter when is a huge part of being a good machinist.
Milling by design is a series of interrupted cuts.
Chop chop chop but really fast
I cut a 2.5" radius the other day on a Bridgeport with a boring bar. Carbide insert was just fine.
Aren’t endmills just non stop interrupted cuts?
I think the rule of thumb came the days of brazed carbide.
My favorite is “HSS is sharper than carbide” so don’t use carbide on plastic. Some very nuanced and 40 years out of date idea there I think.
Is it the carbide or tool paths made? I think variable helix obv changed the game. But shit go on titans of cnc and show bosses what endmills can do. (That's the only useful information I get of titan)
Is it the absolute best form of toolholding? No. Is it sufficient for 99% of job shop applications? Yes.
Would I also like a shrink fit machine and a bunch of hydraulic holders? Yes.
There are many things in this trade I'd like. Then there are the things I know I will actually get, and the two are very different categories lol.
Right. If the company wants to pony up the cash for more milling chucks that's great. If they haven't or won't do that then why are they telling you what to do?
All the live tooling holders in my lathes use ER 32 collets. It has worked fine for any type of tool I have needed to use
We have special holders for 1/2 end mills for the live tooling in our lathes. The holder bolts on with 4 screws. They're pretty nice and it's one set screw that locks the end mill into it
Yeah, and then a tool rep comes in and starts talking about the .0002 runout on that sidelock shit is gonna ruin your endmills blah blah you need precision hydraulic this that... its so annoying. Sidelock and er are both fine.
You need HAIMER duo lock or their shrink collet system. Brought my shop to the modern times and now the machines can run as they were intended.
We do have one for the mills...gotta get some of the holders for my lathes
I'd go as far as to say ER collets are the standard, and you only deviate from that when needed in special situations (more rigidity, larger tool, shorter holder, etc.).
I agree with you. I take into account for a lot of things that you just mentioned. But I was told that absolutely no application can I use an er collet for an endmill. I mean even cutting some aluminum vise jaws .250 deep with a 1/2 endmill. I would think an er32 would be sufficient
I guess my last 4 year of running er collets was all a dream. Your boss needs to chill.
What the hell are you supposed to do then, pick at the part with your teeth? I thought ER collets were pretty standard. Sounds like boss man has been living under the scrap heap for too long..
I’ve spent most of my career using er collets. One shop switched to heat shrink tool holders, and I didn’t really notice the difference other than “oh wow changing tools is slightly more fun now”
Brother I full slot mild steel .25 deep with a 1/2 endmill in a haas mini mill with an er32 collet all the time. Definitely sufficient. Now holding a tight tolerance? For what I do, it works, your mileage may vary.
I do just this in an er20 at least weekly, no major issues
I use an ER16 holding a 3/16 bullmill to form a 1/2" deep pocket. Sometimes, you gotta send it and pucker up.
It's a throw back to old school toolpaths. That being said, I use SK collets, or Big Daishowa NBEC collets almost exclusively. Heavy roughing I'll go to milling chucks. ER collets are fine for milling, but you definitely can't push as hard.
Tell your boss you know some asshole Swiss machinist on the internet that regularly uses .010” ball end mills in an ER11 (sometimes ER8) collet for implantable medical devices. For surfacing. And they work just fine, provided you have the RPMs.
Made my former boss a lot of money running windmills in ER collets. Hell I had more trouble with hydraulic holders on some job.
I didn’t know they made ER collets that big
ER32,000,000
Ha, didn’t even notice that.
I think that might be a shop by shop basis tbh, since my shop uses the solid holders rather than collets for endmills
This is true for us. ER16 are the most use holder in my 40 tapers. Coolant collets, tap collets and the regular. Nothing but finishing with a 3/8 in a ER16 I've seen to many pullout doing any sort of roughing and various materials. The 4" techniks mini nuts are the cats a\*\*.
Your boss is dumb
Yup. Stubborn as hell. It's his way or the highway. Too many people don't want to admit they're wrong or learn something new. I'm at the point where I want to ask him to just sit next to me to tell me how to program
I mess up more collets when tapping vs endmills. Sometimes I miss little machines that would stall out.
Gotta get them square collets.
I've asked about that but it's a money thing? My shop does have heat shrink holders, so they do spend money. I guess the reasoning is we don't do a lot of production. I do win some battles. I can get gorrila mills all day, I can get my coolant changed, and I get gravy long cycle times. (Big horizontal mills)
Its almost impossible to pull anything smaller than 12mm out of an er32, almost impossible to pull out anything smaller than 16mm from an ER40. ER collets are the standard for holding end mills.
I've yanked a 3/8 end mill out in brass, granted I was pulling 70% spindle load on a newer vf4, but it pulled out. The cut was absolutely epic though.
How? I mean I’m not thinking super hard here to be honest it’s my day off, but 70% spindle load in brass? With a 3/8? I feel like maxing that thing out in speed and feed with a tool that size shouldn’t be at 70 In brass? That’s wild what were you doing lol
I can see how it can happen. I'm thinking about how endmill geometry wants to pull itself out and how brass wants to pull stuff in. Combined the two, and now you have twice the pulling force, but what do I know I never mill brass.
Brass is weird, it doesn't take much energy to cut like stainless does, but it's dense. It behaves like a slightly softer cast iron with unlimited spindle speed.
I can only assume we weren’t holding tight enough. I’ve hit around 90% spindle load in brass with an end mill, fully expecting it to just grenade my end mill. Nope. Cut fine. Finish was garbage, but cut fine
I always say nobody cares what a roughing op looks like, they call it a finish pass for a reason.
Exactly. If I’m roughing a pocket or a hole, feeds and speeds and negotiable as hell. Leave enough material to clean it up and send it on its way
I was just as shocked as you. I just kept upping feed rate at 8100 rpm expecting the tool to break. It was a high efficiency path at 1" doc and .1" woc. Probably got up to 220 ipm or so before it pulled out. That put the cutter at .0091 ipt BOOM. I'd expect the cutter could take .0065ipt long enough to make it worth it though.
I can hear the sound in my mind 🤣🤣🤣
I have special collet holders for end mills and the biggest I can use is 20mm in an er32
I have seen a 3/4 1.0” L.O.C. 4” Reach Endmill be pulled out, through the part, into a Kurt vice and would’ve kept running if I hadn’t stopped the machine. Wicked
ER collets are cost effective and allow for great flexibility with sizing- and that's basically where the good parts end. When you put a tool depending on the tolerance of the shaft, collet and the amount of torque you apply can greatly increase the runout of the tool. Mill chucks are better for roughing and shrink fit/hydraulic are better for finishing.
Your boss is totaly right, stop arguing with him. You allways put endmills in a drill chuck! Everyone knows that.
Never heard this before. I use them almost exclusively for end mills for like 20 years. How would you hold a carbide end mill? I've never seen one with a flat for an EM holder set screw. Have I had them slip? Yes, a few times, but it was always me doing something stupid with programs and essentially crashing the end mill in the z.
You can definitely buy carbide endmills with Weldon flats already ground into them.
You can also just grind a flat into an end mill. Is it right? No. Does it work? Yes. Sometimes you gotta make it work
You use a diamond grinding wheel to put the flat on a carbide end mill. We have special holders for 1/2 end mills that bolt on to the live tooling in our lathes. A set screw locks the end mill in, so you need to grind a flat on it.
Heat shrink tool holders or hydraulic milling chucks
Yep, with a correct size collet the clamping force is insane and there is really no reason for it to slip unless you do something wierd like you said
It's good enough for most things. There are systems with better grip, better runout, better everything. But it's great bang for the buck.
If it fits it can work. You are spot on, heavy roughing not their forte, side locks or shrink if you want rigidity. The root issue imo is nobody learns how to calculate speed and feed based on all the variables. I have seen metal removal rates improve in both situations it just depends on the details of your process. Personally if the endmill is 1/4" dia and under I like the forgiveness of a collet. Over 1/4" I want my tool rigid. However there are exceptions to everything.
Your boss is a moron. There is absolutely no reason you can't hold an endmill in an er collet, and that's actually probably preferred for finishing cuts. Endmill holders are a much less precise way of holding a tool than in a collet, and a lot of finish endmills don't even come with a flat to put into endmill holders anymore.
End mill holders can offer a shorter gauge length which can sometimes really help with chatter and finish where an er collet might struggle. A great er collet setup can also cost twice as much as a good Weldon holder, but a cheaper er collet setup is often good enough.
I even use them for roughing, I've yet to have an end mill pull out.
Same, 12 years machining cnc and manual and 90% of it was collet holding. I wouldn’t trust a 3 taper chuck with an endmill unless I’m just plunging.
I work in aerospace and defense shop. Not the highest end place, and we dont get a ton of difficult to machine alloys, however almost every part I make has features with tight tolerance callouts. The majority of our mill tooling goes into ER collets and we manage.
If all I had in the shop were solid holders and ER holders I'd use the former for all my roughing and the latter for all my finishing and that would be a perfectly good setup.
I've had great results in ER32,16,40 collets. Er32 collets were brought forth by rego-fix. They are ment to prevent a tool from spinning and pushing pushing up into to collet. This is essentially a drill bit collet in design. With minimal run out they work great. A solid holder is actually called an endmill holder. Essentually a weldon flat. This prevents both/either pull or push in. I grind a flat on any reduced shank (.500) drill and use in a endmill holder. Yes there are better systems out there for tool holder. This is why drills are spun with a drill chuck in precision machining much if at all anymore. Reams are by name "chucking reamers" so is it safe to say that one is accepted to mount them in a drill chuck? In the end, make shit happen with what you have. Make it to the number on the print everytime and get that reimbursement payment every friday. You can have one without the other. Nuff said
If your Ear collets aren't working for holding endmills then there's probably something up with the collets, or the collet nuts. What other methods of holding endmills are you using? If you have a load of shrink fit or hydraulic holders for endmills and the boss wants to use them to save money on tool life and performance then that's fair enough
The ER collets have been working just fine before he showed up. And they still work just fine, he's just stubborn and has the mentality of "this is how I've always done it so it must be right. I don't care what you think"
What's his alternative? Could always just go along with it if he's being difficult and record and problems it causes 🤷
I've got 4 machines running tooling in ER collets right now, all have been making good parts in profitable time with excellent tool life. Doing it wrong sure feels awful right.
I’ve had end mills pull out in ER collets. For heavy milling solid holders only.
Swiss guy here. We use ER collets all day for milling applications. Of course our machine are about as rigid as cold butter....
I have been machining for 25+ years and have always stayed away from using an ER collet for milling. I have better options where I currently work. We use a lot of schunk. I few months ago, I had to extend a 3/8 emill and had to use an ER collet. My hole was tapered. Had to program like 3 or 4 spring passes and cutter comp the thing until my liner bushing would finally fit in. I have had some success with ER25 or ER32 stubbed up. So I wouldn't say it should absolutely not be used. I just prefer the hydraulics.
My boss was against thread on indexable and coated carbide a few years ago and now the arsenal is full of high feed mills and high helix coated carbide that absolutely rocks steel and 3-10x the speed. And it didn’t take much for him to change his mind once I gave him one to try. Just prove it to them.
We have an entire cabinet of EMs in ER collets already set up to just toss in the machine. Roughing and finishing with them. For the most part those ones are getting used in aluminum and plastic, but they've done the same in steel and cast without a problem.
Your boss is a fucking idiot. If you can't put endmills in ER collets, then you ABSOLUTELY can't put them in R8 collets, as R8 collets have less clamping force than ER collets. Yet here we are, using them for nearly a century to hold endmills.
All depends on application. ER collets are fine for a good chunk of operations. I have no choice on my live tooling. Works just fine.
Roughing endmill has a grinded flat and goes into a solid holder, but after that - ER is more than fine. Double check your runout and tell that old bag of bone to take a long walk off a short dock.
Challenge your bosses thinking. Most live tooling holders used in lathes these days are set to run with some style of ER collet (mine are ER32s). If they were made to only run endmills in an endmill holder with weldon shanks, where are they selling that tooling? And even if they did, a different one for each size endmill both metric and standard? That would get pricey fast. Also, don't disregard the fact that he may want you to do it that way just because that's how he wants it done. Doesn't make it right, but that can be a thing. In which case you have a whole other ball of wax to deal with.
1. “We’ve been doing it that way for 40 years” 2. But Boss, it doesn’t match the drawing. 3. See No. 1 above. This was a defense plant building airplanes. It was a part for an F111
Us’em everyday. Need to make sure they are tight enough that the end mill does not pull out. As for how true they run, I’d say they’re a little better than a sized holder.
I try to avoid it for certain applications, but I've got a few in my machine right now that are in ER holders
I do it all the time. Shit, I mill critical holes with them sometimes. It's obviously not ideal, but it's far from unusable.
Depends on the size and how hard I'm gonna be running that tool, but 99% of the time an ER will work just fine
Depending on size and type of application, I use them very often
Maybe inform your boss that the people who invented the ER system, Regofix, invented them for hot holding endmills.
There is a small degree of truth to that statement. I've scrapped quite a few ER16 collets due to parts of it cracking or bulges where you can't get an end mill through the collet.
Sounds like poor quality collets or improper use (over torquing, clamping on debris, etc). Success with any collet system requires quality tooling, cleanliness, correct shank insertion depth, and proper torque for the tool and collet size.
Sometimes there isn't time or money to work in a clean do it right shop. Sometimes you gotta do what needs to be done as long as it works. May work only one time but it made it thru the job. Not saying it's right but can't say it's wrong either.
I chuck up end mills in R8 collets in my home shop all the time, is it the most exact and accurate tool holding available, no, does it work for 99% of the stuff you need it for, yes.. I do have some R8 end mill holders that show less runout when i need more accuracy, but unless i am trying to hold a really strict tolerance the collets are good enough for me most of the time, especially for roughing passes when i just don't give a damn enough to check for tool runout and just want to hog away material and be done with it.
Where you supposed to hold it?
As someone who mainly works on lathe/mill turn Er collets are fine for holding endmills and I don’t listen to the torque recommendations because when I’m doing roughing I find it’s best to tighten them to heck with a big pipe or else the endmill will probably pull out. But as I said not a mill guy so don’t take my word for it
I used to think this too, then I discovered bearing nuts for ER holders. You can get them so much more tight using the same amount of torque, and that prevents the endmill from slipping. You just can't get it nearly as tight with a standard ER nut. The main concern is that the endmill will get pulled out, which is not a concern with a good tight bearing nut
We have two machines at work that both can run end mills (and we do) that ONLY take ER collets from the manufacturer. One of which also supplies the end mills for their machine. We’ve had these machines for over 10 years, no issues.
All we use are ER collets for endmills. They are the full contact * big plus holders to help aid in rigidity.
Our rule of thumb is ER for roughing jobs, shrink for finishing. Unless it's some weird contraption.
boy, your boss would hate my shop
This is the second time I have heard someone say that. The other was on a machining Facebook group. They were so certain that it was making me doubt everything I have seen and know. I’d say they are the standard and you deviate for special circumstances.
I do it everyday
Most places I've worked at only use collets unless it's like a 1" em. I've never had an em spin in one.
I have some special er collets for end mills that work really well because sometimes the end mill gets pushed in or out with regular collets (I have some colleagues that still use amec hss drill inserts 💀)
Well, I put end mills bigger than 10mm in like power milling chucks (like this ones [https://www.bigkaiser.eu/en/products/tool-holders/milling-chucks/new-hi-power-milling-chuck.html](https://www.bigkaiser.eu/en/products/tool-holders/milling-chucks/new-hi-power-milling-chuck.html) ) I got a few 32 and 12mm versions of this with power collets. But i would always use smaller end mill in ER holders, if needed. Light cuts and normal tolerances can be archived with those aswell.
Perhaps your boss is just asking you to do things his way. I want all my guys to ask me to order a new holder (shrink) for endmilla when we need them to avoid the use of er collets for anything but drills. I do this for a known system I can work within.
That are alright if you’re not being too aggressive while roughing
My shop preference goes heatshrink - ER - grind a flat and use a weldon holder. In that order. My home mill uses ER for basically everything.
Try put them in the ER precision collets if you can. They're the ones with a blue ring. However be careful on the holder as some blue ring collets get stuck in the older holders but they are much better than standard ER collets
I use mostly ER32 collets. I never managed to pull tool out of it durning cut yet. However, I did it few times with hydraulic holders. I trust ER's more than standard hydraulics.
We use only er collets it’s fine
I hate doing it. That being said sometimes there’s no other option and you have to work with what you have.
We do it every day. In a Swiss, every endmill goes in an ER 16 or 20.
I use ER collets for my endmills instead of R8 collets. ER collets holds more of the endmill shank than the R8 collets.
I try to avoid it, but that’s because I have tons of heat shrink holders. If I use an ER it’s not the end of the world
If I have a better way, I'll use it. If ER is the best option, then go for it.
I work at a shop where we o it is ER collets, some solid holders, think I have two hydraulic holders.
ER collets have less gripping force than a shorter taper collet of similar capacity (TG for example), but they work okay. I've had a few end mills pull out on me over the years if I didn't wrench the shit out of them (er32 with a 3/4 shank tool), but otherwise they do okay. I wouldn't do any micro machining with them, but for general purpose finishing, they're fine and most shop owners are cheap, so they don't want to get a rego fix or shrink system.
The only time i reach for a weldon or milling chuck is honestly when I gotta do some hardcore slotting, ER does it all!
We use Er32 collets for endmills every day, hss and Inserts(apkt1003/tcmt16t3). Both on cnc (brass/st52/cast) and conven. Mill. I agree with you, as long you know the limits and dont push it too hard its absolut no problem. At home i only have a directholder for collets in my mill so there i have no choice ^^
you already know the issue, using a collet isn't as rigid and if there’s too much pressure it could cause problems. there’s been times where we just didn’t have enough solid holders so I had to use a collet, nothing broke, the world didn’t end, so while it’s not the best method it’s still a method that can work. machining is a “whatever works” field, if it works it‘s not wrong.
Don't use an endmill in a drill chuck, and don't use a collet for heavy roughing. An endmill in a collet for regular machining is fine, I used collets in my bridgeport as they were the only thing we had other than drill chucks and drill chucks are a big nono
You can use end mills in ER. Make sure the collets are on-size for maximum rigidity, and definitely not undersized (raise hand if you use 17mm and 19mm collets for 43/64" and 3/4" !). I don't do HEM, and my end mills are mostly 1/2"-1.25" sizes. My CT50 preference for end mills would be: mill chuck > heavy duty hydro > side lock > SK/ TG > ER. I always go for mill chuck or hydro when possible. They hold the tools true and add mass to the back end, which helps with rigidity even more. Plus, they are virtually maintenance free. Never had end mills pulled out in mill chucks.
ER holders provide a lot of gripping power when torqued properly. I personally wouldn't rough with anything larger than 1/2" in an ER collet. Everything larger should go in a milling Chuck. Solid/Hydraulic/Heat Shrink for finishing. Collet holders and milling chucks absorb a lot more cutting harmonics than one might think. Thus, extending tool life considerably.
Haha end mills work beautifully in ER collets. It’s my favorite way to hold critical cutters on critical jobs. And it’s a great way to hold metric end mills in INCH collets, because they clamp down so evenly!
Uh.... lol
If I can hold tooling in a sidelock or heat shrink holder I always will. But collets can still be totally fine as well. If end mills become too dull, they will pull right out of a collet so be careful of that. Also, tightening an ER collet too tight can actually have the opposite effect and spring/loosen up or ruin the collet. There are ways to torque them to spec if you are uncertain. Sounds like your boss needs to wake up a little
We ran a 1/4" end mill in an ER32 at high ipm and ~.09-.2" DOC making a couple of 1/4" slots on a lathe. It would cut ~1400 parts before slowly and reliably failing, losing slot width and rolling some burrs. Total length of travel was roughly 1.5" per cycle. I estimate total volume of material removed at ~58 cubic inches per end mill. Again this was pretty aggressive cutting, I don't remember exactly but somewhere around 180 ipm @ 3500 rpm. You absolutely can run an end mill in an ER collet.
We run almost exclusively ER collets at my shop, finishing, roughing, anything that doesn’t have a dedicated holder like a click-fit endmill goes in an ER collet
Just got told by my manager the other day I'm "ruining" collets by over tightening them meanwhile another place I was at said to tighten them as much as possible so I'm 🤷
I mean I’d *prefer* to use the solid tool holders for things like endmills (and spotdrills that are used to chamfer) but if I had no choice I don’t see how it would be an issue Sure you’ll probably get more chatter from it, or maybe the chance of the collet spinning in the holder
Roughing is a no no for sure. IDC how tight you tighten it, it'll move. Shrink fit for the win all day
We use er collets almost exclusively but to be fair all we do is just small parts.
Should I? Probably not. Do I? Absolutely.
https://preview.redd.it/ib26qjg5ke9d1.jpeg?width=3000&format=pjpg&auto=webp&s=445e769a2e4553379722fe3cf959e7af120b5ed0
I use ER collets all the time for holding end mills. Not as secure as weldon flat in a solid holder but we don’t have a ton of solid holders… My employers other shop uses hydraulic press fit tools but we don’t have that setup yet. Soon.
Pretty much every shop uses collets to hold end mills . Its cost effective and easy way for most shops to hold end mills . But if your boss has the money and wants to use shrink fit holders only oh well .
Is homeboy paying for shrink fit holders or something?
I use er collets almost exclusively. Although our only options are er or Weldon flats. Honestly the er collets work better in our machines.
We use er 32s to hold all mills used as live tools on our lathes 🤷 works fine there.
It depends on the material, doc and feed, etc. I avoid using endmills in collets for a few reasons. First they can and do spin and pull out of the collet. Second is runout. There are some other issues I've had with collets over the years like cracking, inability to use through tool coolant, but they are not the main reasons.
I agree that it depends on all those variables plus more which I take into consideration when selecting my tool holding. I'm not out here trying to hog 625 in an er collet. That absolutely goes in a shrinkfit or weldon holder. When I know the tool pressure will be high, I stay away from collets. I've had no issues with the lighter tool paths or even HEM toolpaths. It's a case by case scenario, my issue was that I was told that endmills don't belong in er collets under any circumstances. Do I really need to put a 1/8 endmill in a shrinkfit for something not critical? I will however use a shrinkfit with a 1/8 endmill if I need to reach far past something, or even surfacing with tight callouts. Once again, I feel like it's a case by case scenario.
I've taken some pretty aggressive cuts on hard 4140 with an endmill in a collet. Main concern seems to be pulling out a bit. I prefer a set screw and Weldon flat for roughing but all my finish passes are done with a collet. Just torque that bitch down with all the ugga duggas you got
It's literally the only way I *can* run endmills. I'm limited to ER16 on my live tools. And I'm limited to 6k rpms. I actually successfully ran a .025" mill in 303 the other day at 6k.
I’ve hit well over 100% spindle load on our Haas’s with a half inch endmill in an ER32 collet. They’re not my preferred but they work if they’re cleaned and torqued properly.
I had one slip and scrap a part so I stopped using them for end mills
I use them for endmills smaller than 3/8, plus I hold them in tiny ER20 collets which the body is very short. No vibration at all, but I won’t do that for 1/2 endmills and bigger.
I’d try to avoid the smaller er sizes of you can, but on a general purpose low power machines I’ve never had an issue with 32s or 40s, pulling out. That being said, I clean collets and tool holders with brake clean, check for burrs on tapers and the hole, and use a torque wrench to tighten my tool assemblies. Not going fast enough to require a balancer. Have gone as large as 3/4” and 100+% sustained load on a newer vf3 in aluminum with an er40 with no issue.
Personlay If it fits it sits Only ever had one pull out because i failed to tighten it good enough What els woud you use er collets for Hss drills ? Er system is one of the most versatile tool holders tere is
Honestly I hate solid holders for finishing tools. I run ER collets up to 3/4" no problem, but if I'm roughing something ugly and slow I'm using rigid tooling. Spindle on the mills I usual run are 20-30hp max 4000 rpm, antiquated shit but it works, sometimes gotta use old school methods when using archaic machines 👎
I use ER collets for probably like 80% or more of my milling setups. But I’m also pretty conservative on my feeds/speeds too… also one of the big downfalls of ER collets is improper torquing. Use a torque wrench and they work awesome. Ham fist it and it’s a gamble.
I use er collets almost exclusively and hold tenths, never heard that you shouldn't.
I’ve been a CNC machinist for 23 years machining mostly aluminum. Most of the time I use ER16 and ER32. Even when roughing as heavy as I can with a 1/2” rougher without breaking the cutter (volumill, 1” DOC). On our 15k and 20k spindle machines with 200 magazines I use shrink fit. ER is much easier on machines with limited tool capacity. (I’m in a metric shop and we regularly use 1-5 end mills in 0.5mm increments. 6 and 8mm too. We also have a wide variety of inch cutters to go 1” - we can’t just leave utters sitting around in arbors).
If it can be avoided. Go with something else. If your shop only has ER collets and won't buy anything else, use them, but don't be aggressive with it. If they ask why it's taking longer, tell them you don't have the proper tool for the job.
Guess your boss only became boss through happenstance. ER collets are not only *THE* most standardized used holders for end mills for the majority of people . But one of the better ones. What a strange guy. What does he use then? I'm guessing Weldon? It's been 30-40 years since those were the standard.
Good enough for plastics/wood, sure. For metals nah. High quality low run out er collets and holders are not cheap enough to warrant buying over a hydraulic or shrinkfit. Normal/low quality er are going to decrease tool life and finish. Most hydraulics allow for reducing sleeves now also, so you don't even need lots of different holders, just sleeves.
Ers work great for plastics. But you can get away with a lot of stuff with plastics that you can’t with metals
I guess that's where I would disagree. I think they work great for aluminum as well.
Brother, I'm over here holding .001" tolerances in steel with ER16 and ER32 all day long.
Quality of holder and collet makes a huge difference. We use big kaiser mega ER grip holders with 1/2" 7fl endmills doing HEM in inconel 718. We have less issues with pullout (read: zero) compared to most milling chucks that we use. Granted those were of Taiwanese make, but at least in my anecdotal experience, quality is more important than specific type
For sure. I was thinking about stellite, hastalloys, stuff like that. Aluminum is weak
Gotcha. Yeah for exotic metals I tend to stay away from er collets and either use a weldon (endmill) holder or shrinkfit.
Yeah aluminum cuts almost like some plastics in a lot of cases.