[Davidimurray]

Hi

I've now got my converted Denford Starturn lathe whizzing away under Mach3 control and it is brilliant! I've just got a new quikc change toolpost for it and I'm now looking to sort out some indexable tooling for it.

The question is what tool to go for? Anyone got experience of what tools to use on a smaller lathe ?I've heard various suggestions but mainly from people with big machines - e.g. CCMT, DCMT, DNMG etc etc.

Cheers

Dave

[RotarySMP]

I have been using TCMT on mine, because I got a set of those cheap harbour freight indexable tool holders with the crappy Indian Carbide inserts, which were TCMT. Bought Sandvik inserts off ebay. The heaviest cut you can possibly do on a minilathe is a fine finishing cut from the world these inserts are designed for.

The best shape for use on the minilathe are the long diamond shaped ones with about a 0,2mm nose radius.

[Adobe Machine]

Rotary SMP is absolutley correct..The 1st thing you want to do is REDUCE CUTTING EFFORT.. Use a positive , triangle insert at,or as close as can be to centerline, and you want as small of a radius as possible...Read SHARP..A large radius is OK for large, heavy, stable lathes.
Spend a couple of bucks on some really good tool holders, as thick as your tool holder can take..You need three to begin with, a right hand, a left hand and straight.The good tool holders have 2 or 3 set screws to tighten the insert into the holder , such as a Valenite MCLN - ( R or L) for a 80 degree diamond shaped insert. Best is a CNMP type positive / negative insert.
The real problem is the big tooling companies make insert type tools for really strong CNC machines ..ENCO and some of the rest of them only give you run of the mill triangle inserts, when ,with the smaller machines you need some really sharp, positive rake tooling..
Shopping the tooling catalogues, in an hour you just have to be totally confused ( A mystery, wrapped around an enigma.
Winston Chruchill, 1945, speaking about Russia )Unfortunatley, its just
" Marketing" trying to sell us as much as they can..If you think about what your trying to do, the machine capacities, etc you can see that a sharp, positive rake , rigid tool is going to reduce cutting pressure.


Adobe (old as dirt )