Direct morse taper collets

After doing a search for some info on using morse taper collets instead of ER, 5c etc. nothing turned up.

when i bought my milling machine i was given a boxed collet chuck set as discount, Its an M3 chuck with M12 thread for the draw bar and has 8 collets in the set but no other collets available for the set to buy apart. I think the biggest collet is 14mm.

As I have a lathe as well as the mill I can use it there too using a M4-M3 reduction but I'm still limited to size of material I can use due to collet size.

Looking round for something a bit bigger like ER32 or ER40 i came across the direct morse taper collets that would greatly help with the limited hight available on a small benchtop mill.

Does anyone use them?, pros & cons? what is the largest collet size for Mt3? On ARC the biggest is 18mm is this the upper limit?

I'm debating weather or not to go for them over a Er32 or Er40 collet chuck set and maybe a bolt on chuck for my lathe, I think the er40 would give me a far greater material range but I lose a lot of hight. Thoughts appreciated. thanks

Derek

I have MT2 "finger" collets too as they are called - both the ones that use a drawbar and also Myford pattern that have a draw nut. I don't use them often and not for milling as my machines have either R8 or BT30 tapers. But they are good to maximise height for milling - like R8 collets. My brother in law has a mill with a Myford nose and uses the Myford style collets and he has commented that it's quite hard to tighten them enough since you only have a knurled ring to grip. The ones with a drawbar allow stronger tightening but may be hard to eject. I suspect that 18 mm is the biggest you'll find in MT3 - largest I've seen in MT2 is 12.7 mm (half inch).

Derek,

I have to admit I'm a little confused. Your last paragraph seems to be suggesting that you intend holding material in the collet in your mill? That won't be the case, of course. The drawbar collets will certainly give more height above the table but I understand some people have experienced cutters "walking out" and needing He-man efforts to hold the cutters securely. I rarely use my R8 collets, relying on either ER25 or 32 collet chuck in the mill or even more rarely, a bolt-on ER25 chuck on the lathe to get the ability to hold longer lengths of material than is possible with a morse taper chuck.

Individual ER collets are available from a number of outlets.

John

It’s worth considering how to eject the finger type collets, they can get very firmly fixed if they are tightened too much. The advantage of the Myford type is they eject when the nut is unscrewed. Some machines have a drawbar that is trapped and will eject the collet when unscrewed. If the spindle has ball races then there is a risk of damage if the drawbar has to be struck to release the collet, taper rollers are more robust due to the rollers having a line contact compared with the minuscule area of a ball. The tightening dilemma is when is tight enough to hold the job or cutter without risk of coming loose and not so tight it becomes a mission to remove. I would be inclined to make the drawbar to self eject if using these collets.

Mike

John, I cannot see the confusion, a collet is for holding parallel walled objects close to its size be it work or a cutter or a bolt, all are material, in the lathe the collets are for both work holding and cutters if need be so i can mill on the lathe, in the mill to hold cutters and drills mainly although i have seen work held in a collet and a lathe cutting tool in the vice.

Derek

With regard to Myford collets, do remember they are dead size so need to be used with exact sized material or tooling to ensure correct grip. This will apply to finger collets too.

regards Martin

I mainly use 2MT collets to hold milling cutters in an Emco FB2 clone milling machine, mainly to keep the cutters as close as possible to the spindle bearings. 6,8,10& 12 metric and 1/4, 5/16, 3/8 & 1/2 imperial hold most cutters. They can only be used with very-close-to-size shanks, as there is little finger movement. They hold well but, as the FB2 has a captive drawbar, I can pull them up tight & not have a problem releasing them. IIRC I bought mine from Arc Eurotrade at one of the Harrogate shows many years ago.

RDG Tools 3MT collets go to 20mm metric & 11/16" Imperial - see here

Nigel B

Mike, my mill drawbar is self ejecting, to get the actual drawbar out i need to undo a retaining collar, unfortunately the collar sometimes comes loose too(not often) probably because i don't like tightening chinesium stuff too tight as their material is not really specked for the job. One of these days I'll make a new collar and be done.

Derek

I use an ER25 3mt collet Chuck, which gives me 16mm maximum and suits my SX3 mill as I mainly use an 8mm cutter. On the lathe an SC2 I use a flange mounted ER25 and a 3MT ER40. I prefer to use the ER25 as the overhang is a lot less, and the 3 jaw chuck is better for larger diameters.

I assume you are looking at split sleeves to hold the tool similar to the R8 holders. This is not an option as the Morse taper is a locking taper, that is the male will hold in the female with no other retention device as long as the force applied is into the taper. You cannot change the taper angle of the male, as what would happen if the retained diameter was any size other than exactly the bore of the holder. R8 is not a holding taper it relies on a drawbar to retain it and deforms to retain the tool. You will see that split sleeves are available in morse taper sizes but these are for holding tanged parallel shank drills and no drawbar.

I use MT3, split type collets with a drawbar in my RF-45 mill to hold cutters.

Very handy for a bit more head room under the cutter. Also a bit more rigid as they do not protrude as much from the end of the spindle. 

No problem removing them.  If a light tap on the drawbar does not work, there is a slot in the side of the spindle and a tapered wedge can be inserted to remove the collet. (photo shows an ER collet holder but the split type are ejected the same way).

Paul.

Edited By Paul Lousick on 17/04/2020 14:19:33

I too use MT3 finger collets to hold cutters/drills in my milling machine when I need more headroom. I did use the MT3 collets to hold work in my lathe, but the MT 3 finger collets need a drawbar so they can only be used to hold short workpieces. To accomodate longer workpieces I made a ER 32 chuck for my lathe, this works better than the finger collets. I also have a few Myford MT 2 collets and in my experience they grip a bit better than the finger collets I have.

Thor

This is not an option as the Morse taper is a locking taper

Not correct - Morse taper finger collets are a viable option, see here for a range of sizes

In my experience, they work very well for holding milling cutters. Never had a tool pull out using one.

Nigel B

I have some but use ER more often. Clarkson before that, finger collets even earlier. As I see it there is loads on the net but you need to make your decision as all these systems are there for your choice. Some on here might plump for one way and others(with different kit (or depth of pocket)

Extra available work space is an advantage.

Disadvantage is they are of only for use at the nominal size - each ER collet will accept a range of sizes (dependent on which size ER chuck)

Changing cutters is slower or more of a hassle, generally. Or more brutal (bumping out with a soft mallet). I can have ER nuts already with collets and cutters ready to exchange - just need a couple of spanners to do the job. Not a lot in it but I prefer the ER.

Disadvantage is that work-holding is out of the question unless machined accurately to fit the collet or fitted to a specific arbor.

Basically, I see these different work, or tool, holding systems as complementary - not necessarily simply just one or the other. I have a Clarkson cutter holder as well, but the ER generally takes preference - unless two systems are needed on mill and lathe at the same time. Just like small and larger drill chucks. Just like boring with the mill or lathe. Just like anything that comes up - I look for the easiest way of doing it, and if I don’t have the kit I improvise. I’m not in a rush (generally). However, I’m not going to ditch any of them. As if I did, I would need them for something shortly afterwards!

Many years ago, when I bought my milling machine, I deliberately opted for the MT3 option on the basis that as my lathe headstock was also MT3, I could transfer tooling from one machine to the other.

As has been said, there is a problem in that MT3 finger collets are self-locking and may require a hit, hefty or otherwise, at the tailend of the mandrel to make them release. Now I do not like this because of the possibility of damage to the mandrel bearings, so when George McLatchie in MEW96 discussed his release system, I wasted no time in making my own. Unfortunately, I was not as fast in making a similar idea for the lathe, but I now have. (MEW 289 refers.)

Probably the main snag with these collets that I can see is that the requirement to use a drawbar both to pull them in tight and to hold them in situ means that they can only hold short lengths of material. On the other hand, I have found them very useful when milling in the lathe as they have eliminated the vibration I used to get when holding a cutter in one of the chucks.

Another problem, which hasn't really been a problem, is that they are only available in certain metric sizes, eg 15mm just isn't available. Furthermore, as I have a quantity of 1/4in freecutting mild steel rod, I find myself having to turn the rod down to 6mm before I can use it in the collett. Perhaps the (expensive) answer is to have both metric & imperial collets available.

Finally, I bought every metric collett I could find, some of which I have never used - a complete waste of money.

Peter G. Shaw

The MT3 collet chuck with 8 collets is SOP for a mill.

Its not the same as for a lathe where the collet holds material.

On a mill the collet purely holds the cutting tool, ie end mill, slot drill whatever.

You have 4 common metric and 4 common imperial sizes for the most common shank sizes.

Don't over think things. Use what you have, its all good.

Thanks all for your helpfull answers, especially those that actually read my post before answering, I was mostly thinking as the americans say, best bang for your buck but it seams not to be the case here as there are a few pitfalls in them especially on the lathe that I had not thought of, ie short work pieces only. I've been looking around and the biggest i can find is 20mm so no better of than er32 and er40 is better again other than the cost size wise.

Looks like I'll just have to dig a bit deeper in the pocket as to cover both mill and lathe without too many restrictions and go for the ER system, for now at least, then maybe get a finger collet as and when needed.

Man do i wish i was still in uk at times, things here are very expensive so i end up buying from the UK or Germany but have to wait at least 8-10 days then if not correct expensive to send back and more waiting. Having heard and sean some horror movies for collets bought from china I think I'll get them from ARC as up till now no complaints with the service and I have a few other items in my wish list there, anyone tried their collets and chucks? whats the runout like.

thanks

Derek

I use 3C collets in the lathe and T&CG.

I use direct 2MT finger collets in the lathe and mill and T&CG and rotab.

I use a 2MT collet chuck (up to 5/8' shank = up to 3/4" end mills) in the lathe and mill.

I use 3MT finger collets in the lathe (up to 3/4" ID).

No ER collets were harmed in the making of this comment...