Modifying a wohlhaupter UPA4

I've acquired a cheap UPA4 with a international 40 5/8 drawbar shank. Before I sell it on, I was wondering if I should modify it and keep to fit the fp2. I found a previous thread where the guy was trying to tap the holder m16 and refusing to listen to all advice. I'm wondering if it would be easier to lop off the extended piece and just make a 5/8 to S20x2 adapter, like the ones singer sells for sk40 tools. Any reason why this wouldn't be a good idea? From a quick look it looks like there would be at least 8 full threads engaged.

I don't see why this wouldn't work, unless the material is too hard to cut and thread. Is the shank removable, so you can mount it in a lathe easily? In your place I would buy an off-the-shelf 5/8 to S20x2 adapter, they don't cost much.

Is the OP referring to a Cat40 or NMTB 40?

L7

I have a UPA3 that i use across all my Deckels...(FP2, FP3 and FP4NC)
That head has a 1" straight shank,
Use it on the FP2/3 using the 1" collet to hold the shank......
When it goes over to the FP4NC I have a short (1 set screw) 1" CAT40 end mill holder .
Works a treat...plenty rigid and more or less universal....Change over between the different machines takes about 30 seconds, and with the collet you
or end mill holder you don't need any draw bar threads.
Don't see why you could not do similar.

Your plan to use an adapter centers on cutting off the straight section at the end of the taper...problem is there likely would not be enough thread left in the shank to hold your adapter....
those shanks are pretty hard, think you would have difficulty tapping it deeper....

Cheers Ross

Thanks for the replies. I've attached a pic for clarity. The threads extend down as far as the calliper is indicating.
2021-01-24_07-39-39 by tfrench123, on Flickr
Bruce, I didn't realise there was an off the shelf 5/8 adapter. Took me a little searching but I found it
Anzugsbolzen S20x2 auf 5/8"-11 Zoll (Inch) z.B. fur Deckel Frasmaschine
Ross, I already have a UPA 2 and 3 - the 2 is on a MT2 shank and the 3 is on a deckel S20. I just thought it would be nice to complete the set! Especially if I ever come across a deep bore, the larger bar would be handy. Given that I didn't pay a lot for it I don't mind modifying it.

I think the adapter mentioned is for a Cat40 not an NMTB 40 as shown.

L7

lucky7 said:

I think the adapter mentioned is for a Cat40 not an NMTB 40 as shown.

L7

Click to expand...

If you cut the straight section off the end of the holder ,and given there are enough "Full" threads remaining, then the adapter works just fine.....
Cheers Ross