Question regarding CMD 10 Collet sets

[Englishlever]

Thanks for the thought, I did consider individual collets and a separate chuck, but it made my head hurt just thinking about what I'd need and what I'd get away with.
I bit the bullet in the end and measured a range of cutters and other stuff I've got - all sizes between 6mm and 13mm shanks, then I've my watch and clockmaking stuff which is way smaller than that across a broad range of sizes.
It also filtered into my brain that the headstock spindle on my Myford 7 is MT2, so I'll be using the kit on that too as I've a lot of rod stock to play with.
Ah well, off to exercise Google's servers some more .............

[Jonathan]

I bought some ER25 from eBay - this hong kong seller.

http://cgi.ebay.co.uk/19pcs-ER32-2-2...efaultDomain_3

(He's got the chucks too - may not necessarily be the cheapest on eBay, I've not checked)

The ones I got seem good. I've measured the runout and it's very low.

[Jonny]

I would think again using those chinese ER type collets, they dont grip, take an eternity to change cutters over, even longer to change size. Lose around 30 to 38mm height as well.
If you must choose ER types go for a decent brand name.


Why does no one use finger collets MT tapered collets, essentially the same as R8 types. Can change cutter over in 8 secs and they grip.
Also lose less spindle to table height, practically nothing sticking out.
MT2&3 are good from http://www.arceurotrade.co.uk/Catalo...llets---METRIC just get the one with same thread as your draw bar. You will never look back!
To ondo, spanner loosen 1/4 of a turn, tap with hammer cutter drops out, insert new cutter, tighten draw bar up, job done- simples.

[irving2008]

I use MT3 collets, mine were a set from Chronos I think, tho might have been RDG. The main issue with them is that they are fine for fixed sizes of tooling, but don't clamp down like the ER collects so if your set has 6, 8, 10 you're a bit stuffed if you want to hold a 6.4mm or a 9.5mm drill bit for instance (now tell me you shouldn't use a collet for holding a drill bit!)

[Jonny]

I am going to disagree Irving, i have a full set MT3 metric and imperial for smaller mill mixed 3/8" and M10 from Arc using two draw bars.
On the larger mill i had specific imperial and metrics with M12 thread. I regulary held 1/4" in 6mm MT3 collet likewise 10mm in 3/8" collet, 12mm in 1/2" etc, mine do clamp around 1mm smaller and larger from Chester and Arc Euro Trade. Now got full set down to 3mm and up to 3/4".
http://www.youtube.com/watch?v=Uy8zQ-h4F8I
Mach 3 tool change set up http://www.youtube.com/watch?v=0cM32grBMvo

The ER type from Chester at work are absolutely not worth the plastic box they come in, grolly them up two spanners mate used to annoyingly use a hammer as well, cutter drops scrapping job 8 out of 10 times putting around 3mm cut on. Even when cutters have dropped they are a pain to undo.
May be down to the chinese producer i have had more than my fair share of crap from Chronos namely their interchangeable German sounding tools, RGD and Gloster are good but usually stick with Kennametal or similar.

Regularly hold drills in increments of 0.1mm in collets, less runout and extra height gained!

[Robin Hewitt]

Of course the big difference between MT and ER collets is one is pulled in to the taper the other is pushed.

Pulling means you can't split the collet from both ends so trying to draw it below the stated size is going to put some serious stress on it.

To get the best from ER collets you first need to dump the crummy spanner that came with it and buy the multi tooth job. Gives you a lot more confidence tightening it when you know it can't slip off, more leverage to. Second is scrupulous hygiene, check the internal taper is clean and smooth before you fit it, zap the nose internal and the collet with shop air and look for stickies.

I did try the ball bearing nose but it seemed to make not one jot of difference.

If you are expecting a lot of vibration, give up and go for a Clarkson collet with a threaded cutter. You know it makes sense :tup:

[Jonathan]

I must say I'm surprised at the view on ER collets being expressed here. The Chinese ones that I got seem absolutely fine to me. I've had them a couple of months now and never had any problems, be that cutter creeping/falling out or runout. Maybe with time they'll loose the springiness but so far so good. Surely an ER collet should grip better than an MT collet since it's slotted on alternate ends so that it grips the whole length of the cutter.
I don't have a problem with the cutter dropping out onto the work since you just undo the nut until it's loose, pull the cutter out by hand, then undo the nut the rest to get the collet out. Maybe put a bit of paper beneath the cutter if you're worried about it falling?

[Jonny]

On about cutter dropping whilst milling not removing.

Robin you cannot be serious, even worse than ER and similar.

I can see the point in a lathe spindle but there again the 5C are even better with draw bar, gave mine away.

MT3 or R8 can do some serious stuff short of ISO stuff, lets face it theres two less parts adding to runouts, enough from me had my say.

[Robin Hewitt]

Robin you cannot be serious, even worse than ER and similar.

Nothing wrong with a Clarkson or ER for that matter. If you carry on blaming your tools we will start to suspect :naughty:

[Jonny]

Not blaming my tools Robin, forced to use them at numerous other peoples one was an engineering firm who saw fit to replace with R8 collets after.

The nature of what i do i have to be able to frequently change cutters quickly increasing productivity and have accurate grip ie three cutter changes in 2 mins wouldnt be uncommon. Work it out less than 8 secs to change a cutter with R8 or MT2,3 against how long it takes by other means, excluding hydraulic and air types.

Maybe i am spoiled being brought in to milling with an engineering company using R8 collets, if i didnt know any better i would probably be a lemming your loss. I would never own any ER or Clarkson collet setup, why settle for second best, but would invest in the 5C for other purposes if need arised.
Take the Clarkson - Remove nut, find collet and screw in cutter, place collet with cutter in and adjust depth of cutter by rotating in the thread then tighten up nut. I have known them to run out even visually with the cr, the less parts in the setup and distance from original spindle fixing the better! My dislike is they take an eternity to change cutters, same with ER and other similar types along with cutter slipping or dropping. Just by the time the nut is removed i could have in a new collet and cutter fully tightened up.

A good tip while i think of it is make up a spindle lock if not fitted whichever type of rotary clamping system used.

Now i may have figured the source of the ER and CMD cutters slipping and dropping problem with all chinese and proper expensive English and German made examples. The nut binds and theres a limit to how tight the collet will go. You will know this when you have a cutter drop and the nut is tight still!