ER32 collet chuck holder stuck in spindle

[GRAUBELE]

Hi xpylonracer

To do this, I first have to remove the three-jaw chuck from the main spindle.
As far as I remember, the spindle mount is a very unusual system on this "Asian copy" of an EMCO Compact 8.
I've never seen a spindle mount like this before.
When I bought a very high quality Roehm Ø 110 mm ( Ø 4,33 in) three-jaw chuck many years ago,
I had to search for a long time until I found something suitable.
Then I had to make an intermediate flange out of gray cast iron for the three-jaw chuck as an adapter to the main spindle.
I'll make you a sketch, but give me some time.
But I can only determine the dimensions for you with a caliper and a protractor.
For the cone, this is more of a rough estimate.

Dieter

Roehm Ø 110 mm (4,33 in) three-jaw chuck

Spindle mount

Gray cast iron intermediate flange

Three-jaw chuck mounted on the flange

 

[GRAUBELE]

Hi xpylonracer

I measured the spindle flange with my simple measuring devices.
(caliper, depth gauge and protractor)
There is an inaccuracy (diameter 36 and 38) due to the radius and bevel on the cone.

Dieter

 

[user 284]

At one time I had a very good link to all the DIN specifications for at least a dozen or more commonly used (past or present) lathe spindle mount types Dieter. For whatever reason, any of my search terms today refuses to find a link to that same PDF. But there's at least 3 different versions of the spindle mount your lathe uses. And afaik there all designed to use studs screwed into the back plate and nuts behind the spindle flange. One uses stud/bolt holes much like yours, but with a straight parallel stub end on the spindle. The second uses that same straight spindle stub with enlarged clearance holes through that spindle flange so the nut on the stud can pass through those holes. There's a pivoting plate loosely attached to the back of that spindle flange with bored and milled key shaped holes. In use, the studs and nuts are slid through the spindle and larger holes in the loose plate, that plate is then partially rotated and the nuts tightened. That semi loose plate acts like a set of thick washers. I've seen some references calling it a bayonet mount.

The third is exactly what you have with the tapered spindle nose that in my opinion is the much better and more repeatable chuck location method. But it is a properly recognized spindle mount with it's own DIN specification. I just can't find a link for you with it's exact dimensions. It is fairly rare and I don't think very many lathe manufacturer's have used it. But after a bit more checking, what you have might? be a DIN 55207 found on page 22 of this PDF from Forkardt chucks. https://www.forkardt.com/wp-content/uploads/BA_Fplus_E.pdf The drawing does show the use of studs into the back plate and nuts used to tighten the back plate and chuck onto the spindle.