ER32 which end mills

I have a Clarkson autolock imperial type milling chuck which holds end mills with a threaded end and gives positive end location. Can I use these end mills on an ER32 chuck and how do you get the same positive end location? Reason for question is that an ER32 is cheaper than buying a set of metric collets for the Clarkson.
BobH

I'm in a similar situation, but with an ER25 chuck. No problem with holding Clarkson type cutters, but I don't bother about positive end location. In any event, I find end mills tend to pull out rather than push in if insufficiently tightened.

Clive.

Done up correctly you will have to try very hard to push the cutter up or have it pull out of an ER chuck.

Threaded, plain and Weldon shank cutter s can all go into an ER chuck

Can't say I've looked in detail at prices but there are endless Clarkson collets for sale on Fleabay. I did it the other way round; I got metric collets with my Clarkson copy and bought imperial collets on Fleabay. I've also bought the larger Clarkson chucks and metric and imperial collets for reasonable prices on the same place. Mind you that was some years ago, and there do seem to be a lot more commercial sellers now, often with inflated ideas of what items are worth.

Andrew

Speedy, I have both Clarkson and ER32 collet chucks and both hold equally well under normal use. However, if I have a threaded mill suitable for use with the Clarkson - then I always use it.

I have had a mill move out of a collet chuck when working it hard (on a large Bridgeport mill - with a large & expensive work piece that I'd just surface ground externally) - and it didn't move out just a few thou either. I cannot remember the exact set-up details now - I guess it was probably an MT-type collet chuck (non-Clarkson) with a 1/2" mill fitted (which I know was tightened up) but I can certainly recall how pee'd off I was at the time with the unwanted groove it cut.

So although I've never had a problem with my ER chucks (and nor should anyone else under "normal" circumstances) - I still prefer to use the Clarkson when given the choice. Frankly, it just makes me feel better...

Regards,

IanT

Although ER seems to have found favour with CNC machines in industrial situations I still find the clarkson system to be reliable in most home workshop situations. ER is useful to set a cutter to a predetermined length but Clarkson will require a tool offset as the length will depend on the cutter fitted. Industrially the cutters will be fitted to a jig and torqued to the correct setting. At home we just tighten until we are happy and if this is not tight enough the cutter may move. Without wishing to reignite the "how to fit a cutter" to a Clarkson chuck debate the end location is positively defined for a correctly fitted cutter but for ER if you are a bit limp wristed with the torque for the nut it is possible for the cutter to move which is the last thing you would ever wish for. So far I have not suffered the movement of a cutter so I suppose I have something to look forward to.

Mike

Hi Bob,

Where I live milling cutters with a threaded end is very rare, Weldon is the normal, so I use ER collets to hold my milling cutters, I also use ball bearing collet nuts and have never had a cutter move in or out of an ER collet.

Thor

+1 for bearing collet nuts.

Definitely the way to go IMHO.

Jon

Interesting! I have just gone down the ER route having previously used a similar tapered collet system but with only 3 slits down the collets. I also have a pucker Clarkson for the (increasingly rare) threaded enders.

Anyway, first trial with the ER25 set showed the cutter was pulling out on a modest cut with a freshly sharpened 16mm end mill on 6082T6 ally. Maybe I need to be a bit more ham fisted in the spanner department? Even so, it took a fair bit of getting out again. The ER25 set was from Chronos, fresh from China.

The bearing collet nut sounds interesting - are they on e-bay or similar? Should I bet putting little grease round the inside of the closing nut as an interim step?

Martin

Sorry Martin,

Should of course have given this link in my previous post. ER nuts need quite a lot of torque.

Thor

Edit: Found another torque table that also cover bearing nuts.

Edited By Thor on 17/03/2018 11:05:55

Just as an aside, I bought the ER32 via flea bay, the add clearly said chuck and collets etc, but I hoped a 'C' spanner may have been included - it wasn't. It was exactly as advertised, so I wasn't disappointed, just thought it a bit strange.

Martin, are you snapping the collet into the nut correctly, if done right it will Pop out of the holder as the nut is undone.

Arc do the nuts

I think it ought to be possible to use a nut on a threaded cutter behind the ER collet. This might require the nut to the thinner or smaller diameter than standard, but if you really are concerned about the cutter moving this could be an answer. In my experience they don't come loose anyway.

Cheers, Tim

A good tip, there, with threaded cutters and ER collets - for the smaller end of the cutter size range. They can sometimes be a bear to tighten as one really needs three hands for the job, or some way to retain the cutter until gripped by the collet (unless the mill has a spindle lock).

Thanks for the link Thor - they look like pretty high torques to get on the C spanner as supplied! Certainly a bit more than these arthritic hands can cope with these days.

Jason, Yes I am up to speed with locking the collet into the closing nut.

Thanks to you both.

Martin

NDIY, my collet chucks all have spanner flats on them so i spindle lock is not required (just a large single ended spanner) and I would suggest only purchasing this type if buying one. They can also be held in a vice if needed for tooling fitting or removal. If i had one without the flats I would consider grinding some on it.

Martin C

I have one collet chuck (ER11) with a hex nut and two (ER25) with the slotted nuts, and much prefer the latter as long as they are used with the "industrial" type spanner that locates with the nut in four places. Changing to this from a C-spanner was a revelation.

Brian

Sorry, but I’ve not a clue what you are talking about! I was simply assuming that those with ER holders (surely all have spanner flats?) would realise that operating two spanners while holding a cutter is a bear. Nothing more, nothing less. I have a few wooden blocks I use to hold/prop the end mill within the collet, while tightening sufficiently for the collet to grip the shank.

Oddly enough I find that just about every cutter that I have will stay in the collet when loose so that leaves me both hands free to use the two spanners (mine has flats too) The only time I need to support a cutter is when using drills that are less than nominal size of the collet plus about two cutters that seem to have a fractionally undersize shank. I do have imperial collets for the imperial shank cutters.

Likewise!

Jim