Depends on the machine and whether you can or need to take big cuts.

I use 12mm tools in my Warco WM290V and I can take cuts which are plenty big enough for me, my opinion is that you don't need 16 mm tools on this type of variable speed lathe, the lathe will stall before you reach the tool limits but that is only my opinion!

Tony

I use a mix of 12mm and 16mm holders. With the 12mm holder I can take cuts that will stall my 3hp gearhead lathe running from a 3-phase supply. The choice of holder is down to availability. Holders for some of the less common inserts are only available from 16mm upwards.

Andrew

Up to a point. They're more rigid, which is good, but can get in the way, which is bad. I have a selection of tools between 12mm and 6mm for a WM280. Most used 10mm with 12mm a close second.

From memory my 280 has about the same motor power as a 290, and it can take deeper cuts with 12mm tools than I'm comfortable with. I like to run it so it sounds as if the motor is working hardish, not being flogged. Although the motor and VFD are both fan-cooled, it's still a hobby lathe.

Dave

12mm:
I use 12mm (330 swing lathe 160mmm chuck) most of the time, however the 10mm set I got has better inserts and sometimes on aluminium I use these. I also have 16mm HSS tools which I sometimes use.

I got some tuff doublesided inserts from somebody and made a 12mm toolholder for it as well as modified a less used 12mm toolholder for it. These inserts required a 9 degree modification to cut properly, but they last.

I found the inserts that cost a packet the same as one quality insert, does not last well, and I probably won't buy them again once depleted..