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View Full Version : End mill holder or collet?



pensacola8
03-14-2015, 01:40 AM
Hello, I'd like to hear the pros and cons as to which is preferred--end mill holders or collets. I know they both grip end mills or other cutters differently but the overall function seems the same. I'm I missing something? Which is the better way to go and why? Thanks.

Gary Paine
03-14-2015, 01:48 AM
Trying to use a collet on some cutters like dovetail cutters can easily lead to the cutter slipping a bit out of the collet.
The end mill holder is by far the best.

LKeithR
03-14-2015, 02:09 AM
..The end mill holder is by far the best.

My feelings exactly--collets can be OK but they can also let you down at the most inopportune moment. End mill holders are a sure thing...

oldtiffie
03-14-2015, 03:18 AM
If the cutter shank is inserted entirely/fully until it "hits bottom" in the collet set and is withdrawn say 3>6mm (1/8">1/4") and then and then only then tighten the collet you should be OK as the collet will fully close/clamp the cutter shank before it "hits bottom".

Probability says that it is more likely that the cutter will run "truer" in an end mill holder that it will in a collet.

But having said that a good collet set and a good/well-ground cutter will do just about as well as the collet holder.

It may be pretty well a waste of time (and effort and money) if the cutter is blunted. chipped or just not sharp enough.

ToolJunkie
03-14-2015, 04:13 AM
Anytime you move the endmill further away from the spindle (ie. using an endmill holder), you lose rigidity and risk adding runout. I prefer collets myself. If you use good quality collets, a sharp endmill, seat your endmill properly, and don't take too big of a bite, you shouldn't have any problems with slippage.

DATo
03-14-2015, 04:57 AM
The only time I use the holder is when the end mill diameter shank exceeds 7/8" (our largest R8 collet). I find no appreciable loss of rigidity or accuracy when using collets. We happen to have pneumatic, power drawbars on our mills so it is easy to swap out both collet and cutter. The advantage, I would suppose, to having the holder as opposed to the collet might be found with mills which are not equipped with power drawbars in that it might be easier to loosen a set screw on the holder as opposed to using a wrench on the conventional drawbar. Of course this would presuppose that all of the tooling being used is (or has been made to be) the same diameter shank as the tool holder. If one had a production job of many parts it might be worth the time to tool up shanks of cutters for the holder because, as I have said, it might make changing the tooling easier and faster ... other than that I'll stick with the regular R8s.

Another disadvantage, for me anyway, of the holder over the collet is that it takes up extra vertical space from the bottom of the quill column to the workpiece. When working on something sitting high off the table this can restrict the amount of movement of the knee of the mill.

DR
03-14-2015, 07:20 AM
Collets are only as reliable as the quality of their manufacturing. Given that a good many HSM's buy on price collets are not a good way to hold end mills.

Even holders with a set screw are not 100%. The set screw can allow the cutter to move very slightly unless the screw completely engages the flatted area. Some aircraft companies add a "whistle" grind to the cutter shanks to solve the set screw problem.

Lew Hartswick
03-14-2015, 10:10 AM
The only time I use the holder is when the end mill diameter shank exceeds 7/8" (our largest R8 collet). l.
Yep. except I switch at 3/4 since that is my largest collet . :-)
...lew...

Rich Carlstedt
03-14-2015, 10:19 AM
Hello, I'd like to hear the pros and cons as to which is preferred--end mill holders or collets. ........ Which is the better way to go and why? Thanks.

Collets are quick and dirty ( meaning they have latitude in fits )
Endmill holders are precise and when worn, should be tossed
Generally the collet holder is bigger and that means a more limited access to deep milling application and sidewall clearance.

If you are the general home shopper, it does not make much difference.
If you engage in critical parts, a collet is a no-no as it allows the cutter to be pulled ( unless you use a Kwik-Switch Acura-Mill Collet which has a locking knob on the cutter).
"Pulling" means that when milling the part, the cutter moves outward and destroys the depth of cut. A serious error in some parts. I had my machinists dab a dot of red nail polish at the intersection of the collet and the cutter. If the cutter moves, it cracks the hard lacquer and is easily seen...even with the spindle/cutter turning. The crack appears as a continious silver streak and the adjacent areas are pink. I have seen cutters pull over .030" ...especially in stainless steel....
When using a endmill holder, insert the cutter and start to snug the setscrew. Once it engages the relief area, pull the cutter outward while tightening the screw. Do this as a habit !
Now when milling the cutter will never descend deeper in the part than planned. If it is "pushed" up into the holder, you will know as the depth is off---but the part not destroyed !.

Knowing the limits of your tooling.....and your work... is what separates good machinists from run of the mill.
The OP has a good question that needs to be addressed and hopefully this thread will do that

There is a concept among newbies that collets are more accurate and "rigid" ...not so !
Anytime you have 3 or 4 movable surfaces , versus a solid part, the winner is the solid part ( A vise is easily understood...but somehow cutters are not ?). This does not even address the part "chips" may play when changing cutters in collets
.... things move in collets and especially those that are double taper collets. They are the worst and I would never buy them
In this world, you can only have one master. I taught that in my tooling classes. Having two tapers leads to conflict....and error

Now you may think I don't like collets...wrong !
They are wonderful, but you don't use a Mike for a C clamp either !
Collets really shine, and most shops have them for drilling. They insure better center-line control and rigidity than a drill chuck (talk about moving parts !)
So get both if you can, but use a endmill holder for the heavier milling and you will be fine

Rich

loose nut
03-14-2015, 10:35 AM
Collets are only as reliable as the quality of their manufacturing. Given that a good many HSM's buy on price collets are not a good way to hold end mills.

.

The same guys will probably buy cheap end mill holders, maybe even more so because they cost more, so the same conditions apply to them as do collets.

In 30 years I have had end mills slip only twice in collets, that isn't to bad. Not really worth the additional cost of holders. Cost comparison based on the fact that I have a full set of R8 collets and I use them all. Replacing them all with cheap holders would be big bucks. Some may get by with only a few holders.

Rosco-P
03-14-2015, 10:36 AM
Double ended endmills are best in endmill holders.

oldtiffie
03-14-2015, 10:40 AM
Not if they hit "bottom".

SGW
03-14-2015, 10:52 AM
I use Hardinge R8 collets, and I don't think I've ever had an end mill slip.

lakeside53
03-14-2015, 10:56 AM
I don't have any problem with collets holding (except once - stupid thing I did with l 1 1/4 inch reduced shank drills in 1/2 inch collet). I use end-mill holders also, but more for cnc Z index repeatability. I have quality collets.

Unless you have end-mills with a flat cut into them, holders don't perform any better than collets, and often worse (at holding). Carbide is particularly a problem if it's just screw pressure on smooth shank.

JoeFin
03-14-2015, 11:57 AM
I would have thought collets were more accurate

Just by the simple act of tightening the tool into the holder with the one sided clamping screw you have forced the tool out of the centerline where as the collet applies pressure towards the center from nearly 360 deg

But - I like most of the responses to this thread will reach for an end mill holder first over the collet.

There are way too many other factors affecting accuracy to a greater degree then the preference of tool holder

sarge41
03-14-2015, 12:06 PM
Like most here, I would use a collet only if taking light cuts and cutter concentricity are primary. (Think cutting keyways). If taking deep cuts are gonna happen, use a toolholder.

Sarge

TN Pat
03-14-2015, 12:14 PM
I prefer collets in general. If there is a problem with tool slippage, a holder comes out. The issues I have with holders have been stated, but - your tool is further from the spindle, further from the spindle bearings. It does grip better in heavy roughing. The end mill would shatter rather than slip, and if the tool is pulled down when tightening the set screw, it cannot pull further.

But I have not had end mills slip down often. At where I work, we have one mill that has this problem - even light milling will cause tools to pull down. Not sure why the mill is still there, but it's a small company, after all. Holders or R8-shank tools are a necessity on it. But on the others, there's no problem. On 4140, I've taken 1-1/2" deep, .025" wide cuts with 1/2" carbide end mills, using a collet; with no issue... it all depends on how tight you get the collet, that is where I think power drawbars are weak...

DR
03-14-2015, 12:21 PM
.................................................

Just by the simple act of tightening the tool into the holder with the one sided clamping screw you have forced the tool out of the centerline where as the collet applies pressure towards the center from nearly 360 deg

But - I like most of the responses to this thread will reach for an end mill holder first over the collet.

There are way too many other factors affecting accuracy to a greater degree then the preference of tool holder

Not sure how far up the food chain you have to get in holders, but I did see an ad once that claimed their holders had the bore offset to compensate for the set screw pressure.

I've never had occasion to check the bore of an end mill holder (not even sure I have the means to measure one accurately to tenths). I know most quality tool shanks tend to be in the vicinity of .0002 to .0004" undersize from nominal for ease in inserting the tool.

Mark Rand
03-14-2015, 12:58 PM
Clarkson autolock collets and screw shanked endmills. better than anything else except shrink fit.:p

justanengineer
03-14-2015, 01:52 PM
Its simple - collets provide more retaining force, a better "grip" if you will and better concentricity. Tool holders are a cheap and easy means of getting the tool length repeatable. If youve got a collection of tool holders and leave the tools in them, AND you need rapid tool changes they win. Otherwise not so much.

Paul Alciatore
03-14-2015, 02:15 PM
There is no clear cut "better". Each has advantages and disadvantages. Both work quite well.


Collets:

1. Better concentricity, at least in theory.

2. Leave more room under the spindle for the work.

3. More rigid due to less extension from bearings.


End Mill Holders:

1. Better grip on the end mill. Less chance of slippage. Or so they say. I have my doubts about one or two set screws vs a full 360 degree contact.

2. Extends further so is a better match to the length of drills used in chucks. This can be an advantage with a round column mill where you want to do all the work at one position on the column.

3. Better positional repeatability when changing tools. In a production situation where tool changes are required this can save time and time is money.


It's your work and your choice.

JoeFin
03-14-2015, 03:00 PM
Not sure how far up the food chain you have to get in holders, but I did see an ad once that claimed their holders had the bore offset to compensate for the set screw pressure.




Interesting ....

Since you obviously have spent more time researching tool holders then I have. Do you have any opinion on Universal Engineering Kwik-Switch 200 work holding with Accura-Flex collets in the collet holders ?

dalee100
03-14-2015, 03:28 PM
Hi,

Bottom line, it's doubtful that many of you here own large enough and powerful enough machines to be concerned about whether you should use collets or tool holders.

As long as you properly tighten a collet it will hold as well or better than an endmill holder in a Bridgeport sized mill or smaller. Such machines are whippy enough as is. I've had operators have collets and holders slip. Always directly traceable to either stupid stunts or forgetting to properly tighten the tool.

If you must simply have the best system, shrink fit tooling is best but a mite spendy.

Dalee

PStechPaul
03-14-2015, 05:00 PM
I started out milling using a Jacobs chuck in an MT2 taper to hold the end mill, and of course I had many problems, mostly with the JT coming loose when side milling where there was no support as there is in pocket cuts.

Eventually I bought a set of end mill holders (about $100/set), and they worked quite well, but I got a lot of vibration and chatter unless I took very light cuts. But I have a very rubbery round column HF mill/drill machine not known for their rigidity.

Finally, probably less than a year ago, I bought a set of MT2 collets, also well under $100, and they fixed the vibration and chatter by reducing the extension of the column as well as the distance from the work to the spindle.

I have occasionally had a tool bit slip a little, but that was easily fixed by cleaning the shank and the collet and re-tightening the drawbar.

Gary Paine
03-14-2015, 06:40 PM
Its simple - collets provide more retaining force, a better "grip" if you will and better concentricity. Tool holders are a cheap and easy means of getting the tool length repeatable. If youve got a collection of tool holders and leave the tools in them, AND you need rapid tool changes they win. Otherwise not so much.

I very much disagree with the grip, and I have a gouge in my mill vice from a dovetail cutter to testify that the collet didn't didn't hold it well enough. Of course, a dovetail is an example of pretty extreme pull out force compared to a conventional end mill.
One other point that hasn't been brought up is that a great many mill-drill machines like mine use R-8 collets with a drawbar, but have no quill lock to allow proper torque to be put on the drawbar. No collet can be expected to hold well without properly tightening it. I've never built a quill lock, it's still on the list. I get it snug and then give the wrench end a whack with the palm of my hand so the inertia resistance of the machine snugs it up.
Since the divot in my vice, I use holders 90% of the time.

Toolguy
03-14-2015, 06:58 PM
Interesting ....

Since you obviously have spent more time researching tool holders then I have. Do you have any opinion on Universal Engineering Kwik-Switch 200 work holding with Accura-Flex collets in the collet holders ?

I ran a Hurco CNC knee mill for quite a while that had a Kwik-Switch 200 spindle. It worked just fine. It's an easy way to do tool changes, but your hand gets pretty tired if doing it all day.

Doozer
03-14-2015, 07:07 PM
Collet = Ford F-150
End Mill Holder = Ford F350

--Doozer

JoeFin
03-14-2015, 07:31 PM
I ran a Hurco CNC knee mill for quite a while that had a Kwik-Switch 200 spindle. It worked just fine. It's an easy way to do tool changes, but your hand gets pretty tired if doing it all day.

Imagine that - that is exactly what I'm doing right now

The 1000 lines of code limit is being a pain today

pensacola8
03-14-2015, 10:32 PM
Wow! That is a lot of good info. And with a great deal of detail. So far, collets are favoured. I'll keep reading. I wish I could tell all of you how much this information helps someone about to buy their first mill. Thank you.

pensacola8
03-14-2015, 10:55 PM
My heads spinning with all the info and advice--and that's a good thing. The more the better.

pensacola8
03-15-2015, 12:46 AM
I wanted the pros and cons and I got them--a bunch. I'm going to print these up and mull over them awhile. I thank you very much for the response.

thaiguzzi
03-15-2015, 05:55 AM
Clarkson autolock collets and screw shanked endmills. better than anything else except shrink fit.:p

+1.

Lew Hartswick
03-15-2015, 09:00 AM
I very much disagree with the grip, and I have a gouge in my mill vice from a dovetail cutter to testify that the collet didn't didn't hold it well enough. Of course, a dovetail is an example of pretty extreme pull out force compared to a conventional end mill.
One other point that hasn't been brought up is that a great many mill-drill machines like mine use R-8 collets with a drawbar, but have no quill lock to allow proper torque to be put on the drawbar. No collet can be expected to hold well without properly tightening it. I've never built a quill lock, it's still on the list. I get it snug and then give the wrench end a whack with the palm of my hand so the inertia resistance of the machine snugs it up.
Since the divot in my vice, I use holders 90% of the time.

It would appear you are blaming the collet for a machine shortcomming. I don't think that is a legitimate complaint.
...lew...

J Tiers
03-15-2015, 09:28 AM
I have had trouble with collet slipping and pulling out. You can SAY it won't happen, all you want, but that doesn't change the fact that I have seen it happen.

Many excuses for that happening.... "oh, that must have been a bad collet". "Oh, you didn't tighten it well enough". "It seems you are blaming the collet for a machine problem". "Oh, this... Oh that..."

Fact of the matter is, there is nothing but the friction of two hardened surfaces holding the cutter in place with a collet. I have had collets slip, but I have never had an end mill holder slip. And I use both. I STILL use both. Just depends what I want. Sometimes I need all the space, so I use a collet, and am careful. I may want the extension, in which case I use the holder. When in doubt, I use the holder.

You doubt the holding power of "Just one set screw"? Are you then unaware that the setscrew hits the cutter in the NOTCH? Unless it shears off the quarter-inch setscrew, it's not going to turn or pull out. And you can tighten it pretty darn tight. The holder fits the taper, and the drawbar will take care of any slip potential there.

Might be better if it was a "whistle notch", where it would always bias to the same place (probably full permitted extension), but if you tug in the cutter as you install it, you will always be "metal safe" in the cut.

With a collet, you need to avoid the notch, so that the grip of the collet is not compromised. Probably an ER type would be better, since the standard traditional US workholding collet has such a short grip. An MT collet is likely to be better, but even there the grip is always at a slight angle. A properly made ER collet and receiver would grip parallel.

Someone else noted that the possible tiny error of the setscrew pushing over the cutter is not going to be any worse than the error of a chinese 0.003" tolerance collet. Probably not worse than a good Hardinge that has been used a few times. And any decent holder is made so that the end mill is a close fit, one that retains air (good compression) and comes out with a sharp "pop" from the vacuum.

Even the extension is not always an issue. I have seen holders with very little extension, just enough to get a screw in the notch.

_Paul_
03-15-2015, 10:30 AM
Clarkson autolock collets and screw shanked endmills. better than anything else except shrink fit.:p

+1

Never had one of these slip ever

Paul

sarge41
03-15-2015, 01:21 PM
pensacola8: Your head may be spinning with all info, but please understand, collets will SLIP and always in the wrong direction. The people warning you that collets do slip are the voice of experience. Good luck.

Sarge

PStechPaul
03-15-2015, 03:56 PM
My only bad experience with a collet was when I tapped the drawbar to loosen it and the end mill popped out and chipped a tooth. I was used to the Weldon type holders where that would not happen.

I did have a collet slip a little when I used one to hold the long shank of a reamer, but it just started spinning when I contacted the work, and it was easily tightened by holding the spindle pulley while tightening the drawbar.

Of course, I have a fairly wimpy machine, and the MT2 taper is probably a lot stronger than others with a larger angle.

justanengineer
03-15-2015, 11:45 PM
...

dian
03-16-2015, 09:01 AM
an er-collet will never slip (nor will the tool), provided it was tightened properly. 180 nm for er-40. you need a holder to do that.

lakeside53
03-16-2015, 12:00 PM
I You doubt the holding power of "Just one set screw"? Are you then unaware that the setscrew hits the cutter in the NOTCH? Unless it shears off the quarter-inch setscrew, it's not going to turn or pull out. And you can tighten it pretty darn tight. The holder fits the taper, and the drawbar will take care of any slip potential there.



I have about 500 end mills (no exaggeration - it's what happens when you buy "lots" at auction ;) ). Maybe 10-20 of them have a notch cut into them. Sure, I could grind them in but I won't. None of my 20-30 carbide end mills have a notch. Carbide is really hard to hold in a single screw EM holder without a notch - collet works well. I rarely see carbide with a factory made notch.

Mentioned above - ER holders. I also have ER32 and ER40. They work well and I like them, but I don't a have any issue with R8 not holding.

JohnMartin
03-16-2015, 01:10 PM
Collets will give you a bit of leeway on size, which might be a plus if you are using cheap end mills. Good end mills in my end mill holders are almost always a pop/airtight fit. That kind of fit has to be as concentric as a collet - even with the pressure of the setscrew. Can't remember the last time I had one too large to fit the holder.

Probably not applicable for most of the users here, but I've got TG100 collet chucks for my mill. While I don't trust the normal collets in spite of their name (TG was supposedly short for Tremendous Grip), I do have a few TG "No Pull" collets. These have plugs in the side that fit into the Weldon notches when the collets are tightened. No way these can slip. They won't hold shanks without notches though, so you need both styles.

Almost all of my HSS end mills have the Weldon notches/flats. Carbide is another story.

Oh, and the setscrews in most of my tool holders have setscrews that completely fill the Weldon notches. Before the end of the flat hits bottom, the setscrew bevel hits each side of the notch - so the end mill cannot move even slightly in either direction.

Rosco-P
03-16-2015, 03:07 PM
My only bad experience with a collet was when I tapped the drawbar to loosen it and the end mill popped out and chipped a tooth.

You are supposed to grasp the endmill with a shop rag before loosening the drawbar so this doesn't happen. Same is true when inserting an endmill in the milling machine collet or while handling milling cutters. Protects your hands from the sharp cutting edges and prevents un-necessary tool damage. Maybe someone wasn't listening to the instructor while in class.

PStechPaul
03-16-2015, 04:13 PM
I did that before taking classes, or at least before that was taught. I learned the lesson the hard (but perhaps most convincing) way, and the price was a Chinese two flute end mill that was part of an 8 piece set that cost about $30. I found that catching the end mill in a plastic yogurt cup works well. The damaged end mill:

http://enginuitysystems.com/pix/tools/Mill_Chipped_1512.jpg

And the collet holding it along with other mills and the Weldon holder:

http://enginuitysystems.com/pix/tools/Mills_Collet_Weldon_1511.jpg

I don't have to worry about protecting my hands from the cutting edges of the Chinese end mills. :rolleyes:

Rosco-P
03-16-2015, 04:18 PM
I did that before taking classes, or at least before that was taught. I learned the lesson the hard (but perhaps most convincing) way, and the price was a Chinese two flute end mill that was part of an 8 piece set that cost about $30. I found that catching the end mill in a plastic yogurt cup works well. The damaged end mill:

I don't have to worry about protecting my hands from the cutting edges of the Chinese end mills. :rolleyes:

Or dull, chipped or otherwise damaged tooling from the shop's toolroom. Do they have a toolroom attendant that pulls dull or damaged tooling from the rack and discards or resharpens it?

PStechPaul
03-16-2015, 05:02 PM
I think we are responsible for reporting any dull or damaged tooling, and we pull and put back all the tools in a large rotary rack with 28 drawers that (slowly) move to access the drawer with what is needed. I'm not sure we have a good tool grinder. There is probably not much money allocated to the machine shop - we are lucky to even have what we have, and many of the machines were saved from the scrapyard when some high school shops were dismantled in favor of something more "modern" and perhaps "safer", and more academic. :rolleyes:

garyhlucas
03-16-2015, 08:29 PM
On the subject of tightening collets without a brake. I got a right angle impact driver I use on my mini-mill R8 collets. The hammering action gets them tight just with belt tension. I watch for the socket to stop turning to know that it is tight. I bought the wrench so my ten year old grandson could do tool changes. We are running Tormach toolholders now and very pleased with them. I won't argue about whether they hold or not, this is a mini-mill, not a Bridgeport.

lakeside53
03-16-2015, 09:18 PM
My BP has a power draw bar - basically just an air impact wrench. No brake ever used. Personally.. I think I can get better control by hand, but life it too short to not use power draw bar ;)

Paul Alciatore
03-16-2015, 10:00 PM
I have never tried using a carbide end mill in a holder, but I wondered about that. I can see where it would not hold without the notch, but what about with it? Do they really hold in a notch? I would think that it would not get a good grip and the vibration may tend to loosen it. Anybody have any problems with carbide end mills in holders?



I have about 500 end mills (no exaggeration - it's what happens when you buy "lots" at auction ;) ). Maybe 10-20 of them have a notch cut into them. Sure, I could grind them in but I won't. None of my 20-30 carbide end mills have a notch. Carbide is really hard to hold in a single screw EM holder without a notch - collet works well. I rarely see carbide with a factory made notch.

Mentioned above - ER holders. I also have ER32 and ER40. They work well and I like them, but I don't a have any issue with R8 not holding.

thaiguzzi
03-16-2015, 11:45 PM
+1

Never had one of these slip ever

Paul

Mine's the Vertex copy, works just as well. You cannot beat the Clarkson, Osbourne type design.

J Tiers
03-17-2015, 08:27 AM
I have about 500 end mills (no exaggeration - it's what happens when you buy "lots" at auction ;) ). Maybe 10-20 of them have a notch cut into them. Sure, I could grind them in but I won't. None of my 20-30 carbide end mills have a notch. Carbide is really hard to hold in a single screw EM holder without a notch - collet works well. I rarely see carbide with a factory made notch.

Mentioned above - ER holders. I also have ER32 and ER40. They work well and I like them, but I don't a have any issue with R8 not holding.

I guess that is what happens when you buy cheap tooling...............:D

I have probably 100 end mills, carbide, HSS, new, old, and I am not aware of even ONE of a size above 3/16" that has no notch. And many of those have the notch also.

The carbide does for sure, new, and old.

Sounds like what you bought was tooling intended for shrink holders, or possibly some other type special-purpose tooling.

lakeside53
03-17-2015, 10:59 AM
lol.. no... mine's top quality stuff. I never buy cheap tooling even at auction, and auction around here is invariably aerospace machine shops that can no longer reduce their prices to meet Boeings latest "competitive bid".

I bought all my carbide new via a local machine shop, mostly 3/8 and 1/2 inch - no notches. I looked at their drawers full (thousands) of those last week - almost all carbide and no notches. They run about 10 VMC's and a couple of lathes with tool changers.

I'm not disputing that notched end mill aren't available; of course they are... I just don't see many of them and don't need them.

Oh.. I did buy cheap tooling once. I bought a selection of ball end mills l I thought said "Made in Indiana" LOL.. closer inspection showed them to be "Made in India". ;)

gellfex
03-20-2015, 03:04 PM
Clarkson autolock collets and screw shanked endmills. better than anything else except shrink fit.:p

Ugh! Worked in a shop with Clarkson, they would slip all the time, and the screw would pull it up. Not to mention the tooling was stupid expensive. The Clarkson only grips like 1/4" at the end of the collet, vs the ER collets I use that grip the whole shaft. I've been real happy with ER's, though I admit most of my work is AL and Delrin. I really like having the whole set and being able to use them on most drill bits over 1/8 without using a Jacobs. I never touch my drawbar except the rare occasion I need to use a boring head.

Mark Rand
03-21-2015, 03:57 PM
Are you sure you're thinking about Autolock collets and chucks? The endmill seats positively against a centre at the top of the chuck and can't move axially. The way that the collet grips the endmill means that the endmill will fracture or the collet will be destroyed before the endmill can slip.

J Tiers
03-21-2015, 05:42 PM
lol.. no... mine's top quality stuff. I never buy cheap tooling even at auction,

Naw... you paid HF prices and got Niagara tooling. THAT kinda cheap.....

But I expect those were not for the kind of usage you think.... COULD be for collets, but the aerospace folks seem to really like the shrink-on stuff.