Dan, I have just finished the same QCTP with 12 toolholders and I uprated the base to 70mm square and made other revisions to sizes to suit. Totally sold on it, so very pleased I did it, in fact was considering writing an article for submission to MEW I've been so pleased. I think it may be an under rated type of QCTP because of it's unorthodoxy but I don't think you will be disappointed.  An internet search will produce another engineer who built one and then verified the repeatability of removing/replacing a tool holder with very acceptible results.

Chris

Edited By ChrisH on 09/12/2020 17:27:22

Dan – my lathe is a Weiller LZ280, a quality German lathe from the late 1960's early 70's now well used but still in good condition/. Acquired it when a boat repair firm went bust nearly 20 years ago. Tool height from bed is 125mm, so bigger than a Myford!

I made 12 tool holders, not yet ground all the tools up to fit yet mind, adapted some holders to take a specific tool and otherwise standardised on 3/8" tool steel. The first 4 tool holders were made from a length of bright steel a bit bigger all round than the tool holder size but I saved some money by buying a 300mm length of black steel cutting it in half lengthways and making 8 tool holders from that machining a bit off all round. By planning the machining and machining all holders in pairs in stages one after the other I got all 8 holders exactly the same size. There are only a couple of crucial (measurement-wise) stages to do but by thinking the machining sequences through before starting and especially how I was to do the crucial bits the actual machining went quite quickly and and accurately and without drama.

Good luck.

Chris

PS – I have added a family photo in Albums

Edited By ChrisH on 09/12/2020 18:33:14