ER25 or MT2 Collets

Looking to buy my first small mill to save using the club workshop machine for larger jobs.

Tooling is an additional cost but I am interested in opinions over er25 collet chuck and collets versus mt2 collets direct in the spindle.

At first glance mt2 collets are cheaper, less likely to be out of centre (unlike an er25 if tightened by a mishandled c spanner), allow more height for a workpiece and are possibly more rigid as they project less.

Yet a couple of opinions I respect suggest the er25 collets are the way to go.

Any thoughts?

Go the ER route - better in the long run. I've standardised on ER32 & ER16 (I have a Taig milling head.)

Worth thinking about the largest diameter you will need to grip...

Regards,

IanT

Edited By IanT on 18/03/2019 09:22:18

A set of ER collets will hold any size, imperial or metric. MT2 will only hold their designated size.

I use MT2 collets for holding milling cutters in my FB2 clone. I prefer them for the reduced overhang from the spinlde nose that puts the cutter closer to the spindle bearings. Not had any problems with cutters slipping or pulling out, though as the FB2 clone has a captive drawbar I can pull the collets in tight and easily release them without having to pound on the drawbar.

The ability of ER collets to grip different sizes within each collets range isn't much of an advantage with milling cutters, as most are supplied with shanks to a standard size i.e 1 - 6 mm cutters all come with a 6mm shank.

Nigel B

I have both systems. MT in 6,8,10 and 12mm, and ER25 upto 16mm.

The ER collets are used almost all of the time, unless there is need for a bit of extra headroom.

The advantage of the ER collets is that each collet has a range of 1mm, (in all but the smallest sizes, then 0.5mm ), so can be used to hold Metric or Imperial cutters.

Mine are used to hold work in the Rotary Table, as well as milling cutters

They can also be used in the Lathe for work holding, even if of a slightly non standard size.

So ER would be my advice.

Howard

This is quite interesting. My Mill is MT4, I have collet sets from ER11 through to ER40. But unless I get the really good ones, it is just not the same as a MT collet or any other direct spindle collet. The only advantage of the ER system, is that when I change to a drill chuck, the head height stays at about the same height for most things that need both drilling and milling. I think that the MT collets will hold better than a ER , simply because there is one less something to not be concentric. Most small cutter come on 4mm shanks, there area few 3mm shank cutters, then there is a few 5mm, but standard is 6mm, 8mm 10mm 12mm, If your mill is 2 MT , 3 to 8mm will most likely cover the range for you.

I'm looking at a set of 4,6,8,10 collets will cover most of what I need.

Neil

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Nick,

Just to clarify my earlier post - ER collets have many uses beyond just holding cutters in your mill. I use them for not only holding cutters on my lathes and mills - but for work holding too (so everything - lathes, mills and shapers). Once you start using them, I think you will quickly accumulate a whole range of ER 'holders' - including ER chucks, ER blocks and Spin Indexers.

Regards,

IanT

ER features:

• Hold a 1 mm range of sizes in one collet. This not much of a benefit if for example you only use metric cutters - you often need imperial to accurately hold e.g. 1/4" and 3/8" cutters.
• But can hold a range of drill sizes. For example I use ER16 in my cnc Novamill and have never seen the need for a drill chuck.
• Probably less accurate depending on how they are tightened, also on how well made the collets and chuck are.
• Eats up headroom to an alarming extent especially on a small mill.

MT features:

• Maximises available headroom, useful on a small mill. Note by the time you have mounted a vice on the table and a chuck in the spindle there may be precious little room for the cutter!
• Minimum projection = maximum rigidity.
• Can be hard to remove if you overtighten (I won't rehearse that one here it's been done to death).
• Only really holds nominal diameter - but you only need a limited range of sizes for the available milling cutters. 6, 8, 10, 12 for metric; 1/4, 3/8, 1/2 inch.

It depends which mill you get really, you have the luxury of choice! Personally I wouldn't get one with an MT2 spindle at all! When I bought my Myford VMB it had MT3 and R8 options but Myford strongly recommended the latter - that's what I would recommend if the option is available based on experience. Collets are cheap, grip like the proverbial, don't get stuck, minimise overhang, and you can get Jacobs and ER chucks with R8 shanks if you want.

Your mileage may vary.

If the lathe and mill spindle-noses were changed from Morse to ER everything will be better I think.

MT3 machined for ER32 and ER25 for former MT2s?

Same change for Milling machine .

.

+1 on that recommendation

MichaelG.

One downsid eto using MT or R8 collets is that it can make it hard to see what you are doing when using small cutters, take this example of teh SX2.7 when standing this is what you see

And not a lot better if you bend down and you ca't get near work if clamps are too close

One option for small cutters is an end mill holder which will still be better for seeing what you are doing even with ER25 or ER32 particularly if using a bearing nut which tends to be square edged.

But for versatility and if you can only budget for one then go for the ER25 with say 6 common metric collets and if you work in imperial get the imperial collets too. Others can be added later if needed.

I also have a set of the Farion er25 collets that Barrie mentions, they are not the cheapest of collets but they are very accurate.

+1 for R8 then you can use R8 collets for big cutters and ER chuck and collets for little ones, perhaps using a smaller ER series as well. R8 are much less likely to get stuck, and is standard on Bridgeports so widely available

Edited By duncan webster on 18/03/2019 14:27:39

I’m guessing the OP mentioned MT2 because that is what comes with the machine. Mentioning other tapers is therefore pointless. We’ll see though if/when he gets back to us! The OP has correctly guessed though that MT finger collets are more rigid and do preserve your Z height. Jason’s point about cutter visibility is though correct on a mill with even a modest size quill. It’s much easier to see what’s going on if you’re using an ER collet system. I started off using MT3 finger collets because that’s all I could afford at the time. I’m glad I’ve got them though because they do come in handy on occasion. Mostly though I use an ER32 collet Chuck on my VMC. I did buy either a 1/4” or 6mm end mill holder once but never use it as the cutters never seem to be quite concentric. I don’t suppose they can be if like mine it has a single clamping screw?

I have a Sieg SX2P 3MT and use an ER25 collet holder. Most of the time the maximum cutter I use is 8mm, I found this to be the sweet spot for metal removal and vibration. Almost never use the maximum 16mm and only use 1/2 inch for a dovetail cutter and 12mm for a fly cutter. ER25 gives me good visibilty around the cutter although I have raised the column by about 75mm as there seemed a lot of waster travel.

On a quick look, the Arc SX2P and SX3, and the Warco WM18 (or a variant) have R8 tapers.

I find the frequent advice not to buy the set of ER collets bizarre. To me, ER collets have two advantages over taper fit ones: each accommodates a useful range of sizes, and that you can quickly change the collet rather than the chuck.

I bought the full set of ER32 collets with my chuck about ten years ago, and quickly bought a bolt on chuck for the lathe, then Stevenson's blocks when they became available. I use the things all the time: I don't hold milling cutters in anything else(I immediately gave away the Clarkson copy chuck), and use them for drill bits when the chuck is already installed. The lathe chuck is excellent for smaller diameter work, and the blocks do the same on the mill. Despite that I have 3 collets that are still wrapped in the shipping plastic. But I don't know when I'll need them, and having to stop work to acquire a £6 tool is a real blow to get work done.

For someone buying their first mill and a basic set of tooling then the £75 saved on the remaining collets can be put towards other items that they will need from the start such as a vice, selection of cutters, etc. OK if you have a healthy budget to splash out on all sorts from the start but not everyone can afford that so getting a basic set that will take the common cutter shanks will get you making swarf.

I agree with ER recommendations, but have one reservation. The statement that they fit all sizes metric or imperial might need slight amendment. bought a set metric ER colletsbut I also have a lot of imperial size end mills and slot drills. I mean a lot; six in a packet, lots of packets, all brand new. I found it hard to get a 1/4" shank cutter into the nearest metric collet without forcing it. Rather than risking damaging anything, I had a look and found that Tracy tools did a set of five different imperial size collets to fit all my cutters, and at a very reasonable price.

Regards Maurice