I have a job that entails cutting an M24x3mm thread into the end of a stainless steel pipe plug. I talked to our local dealer here last week and it arrived this morning, it had a 1" shank, obviously not going to fit in the machine- I had two choices machine the shaft down to 3/4 and put an ATC collar on it, or bore out a 10mm setscrew TTS holder and machine the shank to suit, which is what I did, the shank ended up at .730 and I bored the hole out to suit, put a small flat on for the setscrew and all done. I was lucky that the toolholder had a lot of metal around the hole, more than all the other sizes I have, it was difficult getting the hole big enough to put a decent boring bar in, I resorted to slowing down and putting a 1/2 " carbide endmill down the hole, this worked well but I don't have a bigger one anyway a fair bit of patience and a lot of spring cuts it is all done. I'm not worried about the bit of extra length in the tool as opposed to putting the TTS ATC ring on it, the job is only 20mm thick.
Will
Will