For any given tool-holder, there's always a maximum sized tool it will accommodate. The maximum depends on the lathe and the QCTP that's been fitted to it. Buying a QCTP won't solve all tool height problems at a stoke.

The safest solution is to find out the maximum sized tool that the lathe will take and buy the next size down. In theory my lathe will take 12mm tools, but I generally use 10mm or smaller because they can always be shimmed to fit. Once the size has been identified, it's easy thereafter.

Dave

My cheaper, no makers name QCTP works OK with the toolholders purchased to go with it but the supplier has discontinued the system and now I'm stuck as other makes don't fit or only with difficulty. False Economy! Reason seems to be like what was described by a contributor in a recent copy of MEs Workshop. Another darned roundtoit! I did find that fairly small tools fitted, allowing height adjustment as detailed above by Nicholas. Hefty tools are only suitable for very large lathes tearing off great depths of cut or shapers where there are considerable stresses involved with the tool bashing the work at the start of each stroke.

When I enquired about it, the swing was mentioned(330 in my case) this guides you to a maybe suitable toolpost setup. Then the centerline of the spindle was important and eventually the toolpost you get will allow you to get certain sizes of toolholder with insert tips actually on centre. I can get 6mm, 10mm, 12mm, 16mm on centre, I think i must shim the 6mm, but however if you have enought QCTP toolholders its not an issue anymore. My QCTP Toolholders has a gap of 20mm, I have not tried a 20mm toolholder, it will probably not work, cannot shim down.

I assume various makes will not have the same variances possible even though they qwote from a swing number, was confusining initially.

A lot of beginners seem to want a QCTP. system. I did too and somewhat regret having done so. They are not as rigid as say a 4 way holder and to get the full benefit you will need a lot of holders. This finishes up as being one very expensive exercise.

I do use my expensive QCTP, but revert to a 4 way holder or even mount the tool on the topslide (a la Myford holder if I have any serious metal removal to do.

I also use HSS tooling and indexable tooling. Maybe it is just me, but I can always get a better finish with HSS,

My advice is to use the sizeable wad of money that a decent QCTP will cost and spend it on other real essentials that you will find the need for as you progress. If money is no object then treat yourself to a QCTP system.

Andrew.