FC3 'disposable' cutters in ER Collet?

My Emco Mentor mill, has a non standard spindle and now has an integral ER25 collet holder, ie the female ER taper is the only means of attaching tooling.

I have about 10 collets with nuts that handle 95% of what I need (also have modified boring bar and drill chucks) but no good way of holding Weldon or the very short FC3 type cutters.

Ideally a ready made 'solid' collet with a grub screw would be good, does anyone know if such a thing exists? (say ER25 to 6mm)

I suppose I could always make plain steel blanks and drill/ream in situ, that way the projected length could be increased so the cutter is further away from the bulk of the nut.

Ian P

Edited By Ian P on 09/10/2020 17:19:23

I've had no problem holding FC-3 cutters in ER32, 25 & 16 collets and use them all the time on the manual mill

The problem with any solid adaptor is that you would need a special nut as there would be no give in the collet so it would not snap into the nut.

Edited By JasonB on 09/10/2020 17:31:21

Hello Ian,

Clarkson made straight shank FC3 cutter holders for using with an Autolock Chuck - 6mm and 1/4" diameters with 16mm and 5/8" shanks. I don't think they are available now though but may be wrong.

I have been using two home made versions that fit directly in my mill spindle for many years - they are easy enough to make just ensuring concentricity is all that really matters. Made from tool steel but unhardened they have more than lived up to expectation - been using the mm one this very afternoon

Hope that helps some

Ramon

Clarkson made an adaptor for FC3 which was simply a dummy shank with a precision fit socket and pinch screw locking. You will need a metric 6mm and imperial 1/4” if you use both. I would use the same plan for ER25, a plain shank and reamed hole machined at one setting or bored in situ. The FC3 shank is a bit short for direct holding in the collet and an adapter will improve cutter visibility, the cutters are very small so the loss of rigidity will probably not be a problem.

Mike

i see Ramon has said roughly the same but he’s quicker on the draw than me.

Edited By Mike Poole on 09/10/2020 17:44:09

Hi Mike, yes thats just what I was thinking of

I have just had a look on google - can't find an image of one anywhere but heres a picture of mine that may give Ian an idea

The two tool holders are bottom right beside the un-blacked 10mm dia version. All this tooling is 'soft' but made from tool steel - similar grade to silver steel, The five collets are from silver steel. I remeber my foreman at the time telling me they would be no good if they weren't hardened - well - they are still in use today

My old Linley mill has a spindle that takes Schaublin collets - basically a half size R8 - no tooling or collets were available when I bought the mill hence the need to make some. This is all well over 35years old, the collets even more so so has stood the test of time

Obviously the drill chuck, cutter and boring head are bought in

Hope that helps Ian a bit more

Ramon

I have one threaded shank Clarkson adaptor for 6mm FC3 cutters, I believe it is the 16mm fitting, so if you got hold of one, it would work in er25.

Edited By old mart on 09/10/2020 18:30:08

I see other folk have been posting whilst I've been playing with a camera.
I also have the one Clarkson adaptor, shown here in my album of Milling cutter chucks to give a feeling for size.
I do sometimes use it in an ER25 chuck as it's less bulky than either my Clarkson or Tiitanic milling chucks, so sometimes allows easier access to the work in hand.

Amongst my other bits and bobs, I have a Quorn grinder, so I made an arbor for that, but rather than taking a wheel directly, it duplicates the collet chuck on one of my die grinders.
This allows me to use mounted points in the Quorn, the two collets being ¼" and 6mm.
I've not used it for much yet, but the idea was that I could use the Quorn head on the lathe as a toolpost grinder, with mounted points for internal work.
There's no reason why something similar couldn't be constructed with a parallel shank along the lines of the top one in the image, but shorter and slimmer.
I made the long one at the same time whilst I was set up for the smaller arbor, so I could use it for holding FC3 cutters for re-sharpening in the Quorn on a conventional wheel. My ER collet chuck is a 25, so the whole assembly is quite chunky for small grinding jobs, hence adding this one.

The official Clarkson 6mm one is shown lower right for scale.

Bill

I have two 6mm ER25 collets but the parallel part of the FC3 cutters is awfully short compared to the length of the a standard ER25 bore so only a short part of the collet grip length would be in engagement which I understood to bad for the collet.

The other factor is that the diameter of the collet nut restricts how close one can mill near any obstruction. For fairly small cutter diameters (less than 2mm) I can hold the cutter in the Albrecht drill chuck (very low loads in plastic or non ferrous)

I could make my own 'solid' un-split collet replica's but as the auto-extract would not work I think I could revert to a external circlip but then I'm not sure whether a ball bearing nut would like that.

Ian P

Regofix say not less than 2/3 of collet gripping surface should be used.

My 6mm and 1/4" ER32 collets only have that size part way through and an FC3 just about contacts all that area stopping about 1mm short

Edited By JasonB on 09/10/2020 19:41:53

Some of my ER25 collets (a mixture of cheap Asian and some quality european ones) have bores like your example but there does not seem to be a particular diameter value where the bore changes between the two types. Bothe my 6mm collets have full length bores.

The overall diameter of an ER25 nut and its closeness to the job surface with an FC3 fully gripped is still a limiting factor.

Ian P

The diameter at which the collet is relieved also varies with the ER-series number.

For as close to gospel as you might easily obtain, have a look at Regofix' site as I believe they have dimensioned drawings.

For slimline, have you considered changing the closing nut? There are generally two types: the one with spanner flats or hex. and the type with a pronged spanner.

You could also buy an ER11 or 16 chuck on a straight shank and hold it in your ER25 chuck for reduced girth but increased length.

I agree 100%, I have never had issues with FC3 in an ER25 chuck, as long as it is nice and tight. I have got 1/4, 3/8 and 1/2 collets as well as my metric ones, specifically for holding imperial cutters.

I also have a couple of shop made FC3 holders from before I made an ER chuck, they are very easy to make, but ream them to size.

Neil

Bought an MT2 Autolock clone for my 4speed Emco head soon after purchase of same. Easy job to make Weldon "Adaptors" for both 6mm and 1/4" to screw into 1/2" chuck "Collet"

Can't beat positive cutter retention.

Regards Ian.

Ian P -- pretty much everything has been said, I too adopted Ramon & Mike's method some 50 plus years back when FC3 cutters appeared, I used 5/8" Silver Steel bored and reamed to size with a 4BA grub screw to lock the cutter. Still have them and use regularly.

The only other way you could consider is purchase and ER11 or ER16 chuck with a parallel shank to suit you largest ER25 collet and use this for the FC3 cutters.

Regards John

Is your spindle hollow?

If so you could make up a holder with the shallow angle of the ER25 and pull that into the nose with a drawbar, this would have the advantage of doing away with any form of nut so you could get closer to the work

Edited By JasonB on 10/10/2020 14:54:15

Sadly the spindle has no through hole so no drawbar options.

I could use a straight shank to ER11 extender, I would want to shorten the shaft and it would be more flexible solution in that it would hold a wide range of small diameter cutters and drills rather than just whatever solid ER25 shaped FC3 adapters I made.

I have just seen a '16mm Straight Shank (Plain) ER11 Floating Tool Holder for ER Collets' on the Cutwel site, The device in the picture looks the part, but I can see no description of what the 'floating' bit is.

Ian P

I think the floating ones are for use with the ER collets that have a square hole in them to take taps so they can ctr themselves.

You would be better with a plain 12mm shank ER11 and mini nut which is only 16mm OD, probably have to cut down a longer shank, ARC do them as well as Cutwel.

Might be worth looking on ArcEuro site here **LINK**

John

Edit Jason beat me to it !

Edited By JohnF on 10/10/2020 18:41:06

One cheat you can use with an ER collet system is the one I use when holding Rotabroach (3/4" Weldon) cutters in a 19mm ER32 collet. because the Rotabroach cutters' shanks aren't long enough to be fully engaged in the collet, I've made a 3/4" top hat that sits behind the cutter's shank and presents a 3/4" diameter to the bottom of the collet and a smaller diameter between there and the cutter's shank.

This allows the collet to close parallel and grip the cutters well even though they aren't long enough. This might work well when trying to get the last bit of length out of an FC3 cutter.