ER40 collet lathe chuck fitting

[tom_tom_goParticipant @tom_tom_go]

I have a metric import lathe that is similar to a Warco VM240 and would like to fit an ER40 collet chuck.

The lathe spindle register is 52mm (my ME group suggested it may be Imperial measuring 2" instead) but I can't find a commercial back plate that fits with a PCD of 75mm give or take. I wondered if I would get away with fitting a collet chuck to the spindle directly as it has a register, however, there does not seem to be a 100mm collet chuck out there with a 52mm recess to fit.

I am fairly new to ME so maybe I am missing something obvious in sourcing what I need so I would appreciate advice or suggestions as to how I can get a collet fitted to my lathe.

Thanks in advance,

Tom

Edited By tom_tom_go on 18/10/2022 21:08:53

Edited By tom_tom_go on 18/10/2022 21:09:25

[tom_tom_goParticipant @tom_tom_go]

[OldironParticipant @oldiron]

Does your spindle have a 3MT taper in the bore ? RDG do a 3mt to er40 collet holder.

regards

[HuubParticipant @huub]

You could make (turn) a backplate plus collet holder your self on the lathe. I have made several and it is not difficult. This self made collet holder will run true, probably better than any thing you can buy.

Give it a try, it will cost some time and a piece of steel.

[EmgeeParticipant @emgee]

Hi Tom

If you can turn a ring of a thickness to suit the backplate register with a 72mm OD and 52mm ID you could use a 100mm diameter ER40 chuck backplate, this would enable any length to pass into the spindle.
You will have to drill the fixing holes to suit the spindle fixings PCD of 75mm.

If the bottom surface of the backplate is true to the front face then you could drill the fixing holes to suit your spindle and bolt direct but using a DTI to check it is truly centered before and after final tightening.
This would likely only be the way to go if the lathe was always used with the ER40 chuck.

Emgee

Edited By Emgee on 18/10/2022 23:17:37

[JasonBModerator @jasonb]

Just use a slice of 100mm round bar or a blank backplate casting.

Hold in 4-jaw and face, then bore out to fit your spindle's 52mm.

Remove from lathe and drill 3 holes for the flange studs and another three on the correct PCD for the chuck. Tap all six holes as required.

Fit 3 studs and mount the part machined backplate onto the spindle, skim the OD, face and then carefully turn a register (72mm? ) on the backplate to fit the chuck.

Fix chuck to backplate and job done.

[tom_tom_goParticipant @tom_tom_go]

Posted by Oldiron on 18/10/2022 21:30:00:

Does your spindle have a 3MT taper in the bore ? RDG do a 3mt to er40 collet holder.

regards

It does have a 3MT taper in the bore but I would like to be able to pass bar stock through the headstock. Also, I assume you would need to make a drawbar to screw into the 3MT collet chuck as the bore on my lathe at least has no thread.

[tom_tom_goParticipant @tom_tom_go]

Thanks for the other posts guys.

Looks like I will have to make a back plate although I have seen today that Warco will supply one for your particular lathe spindle but I have messaged them to check my lathe spindle register size of 52mm as it does not sound like a standard size to me that Warco would supply for a 100mm back plate (my lathe came with a 125mm back plate attached to a 3 jaw 125mm chuck but I don't want to disturb the fitment and reuse the existing 125mm back plate).

[tom_tom_goParticipant @tom_tom_go]

Updating this as it might help others one day, 52mm for the lathe spindle register is normal for the current VM240, VM250 and VM280 Warco lathes.

Back plates are available to purchase from their website, part code 5444.

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