I bought some ER25 from eBay - this hong kong seller.
(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.
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.
Last edited by Robin Hewitt; 02-09-2010 at 07:14 PM.
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!)
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".
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!
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:
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?
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.
Dont get me wrong, I like my MT3 collets and they will clamp down some way, but they wont hold a 6.4mm in an 8mm collet, though 9.8 in a 10 was OK... I couldnt find an 'official' spec on how far they should clamp down and I wasn't keen on tightening up the draw bar any further....
I have been contemplating buying an ER set... but so far the need hasn't arisen.... I have a Clarkson colletchuck that came with the lathe (at least I think thats what it is) but no threaded tooling and what I've seen advertised is expensive...
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