M42 for Bellows

the 100mm would be too long for stuff like 1:1 slide copying.
You need something like 65mm to work with the Pentax kit.

This is a cracking K mount bellows set on ebay for
£161 BIN (Czech Republic) The K mount which is very rare
would be expensive from Novoflex (although the Pentax K/M42
adapter on a 42mm belows would be just as good). The 105mm
lens could well be made by Schneider. Double rail as well.

It doesn't say if the lens is removable and what fitting?
Might be something odd like M41.3?

ebay_BIN

I did consider using an enlarger lens Ken, but the two I have are both f5.6 and holding them in place I found the viewfinder way too dark so didn't even bother looking for a step down ring..

Anyway, I've been keeping an eye open on fleabay and a very nice 55mm f1.8 Tak. was delivered by the postman about 30 minutes ago

Focusing ring seems a little stiff about halfway through its throw but apart from that and a few specks of dirt the lens seems in good condition. Got it for just short of £30 including first class registered post so I'm a very happy bunny.

Just need some decent weather now.

Algi: too late now, I've already got my M42 ones (also twin rail), K mount would have been very nice though.