Metal Lathe ??????

[taiwanluthiers]

The other problem is power. Let's say you're cutting large diameter material where the surface speed is quite high. For once, it ought to be high enough to actually get a good surface finish with carbide. You touch the tool to the work, and it shoots out a tangle of metallic silly string. The long, unbroken chip wraps around the part and ruins the surface finish, and maybe flays the flesh from your bones too. You want to get the chip to break, you're using carbide, so have little control over tool geometry. About all you can do is increase the depth of cut to get the chips to break, and put and end to that silly string. (At least that's the only thing I know to do. I should in no way shape or form be considered any kind of expert or authority on anything.)

Cut the number of passes you were going to do in half, take a much more aggressive cut, the C's and 9's are flying, the surface finish is gorgeous, and... the light go off, because the breaker tripped. (Having lights on a separate circuit would be an excellent idea, but my panel is totally full.)

I gave up on getting a good surface finish with carbide with my 10" x 22". The spindle doesn't turn fast enough most of the time, and even when it does, the lathe lacks the power to do all the wonderful things you see the Youtube guys doing on their big tool room lathes.

You need to use inserts that are designed for finishing... What I meant was larger lathes, ones more than 20 inch swing, can only spin at 1000rpm at most. Lathes between 12-16 inches can spin at 2000rpm at most. Problem is most those insert are designed for CNC which spins much faster.

10 inch lathes are toys IMO. You really can't even cut more than half a millimeter depth on them.

 

[mmcmdl]

CNC's have constant surface speed while manuals don't , thus you can program the speeds to the inserts you choose . The major difference in the cnc vs manual lathes is cncs don't break the inserts . The canned cycles automatically retract the cutting tool after each cut . Most inserts break when trying to hand feed to a stop which is pretty much pushing the material off . I had a max speed of 5000 rpm on the Makino CNC lathe . Depending on part size , I programmed a max speed of 2000-2500 RPM . Collet work you can crank it wide open , but larger parts will and DO come out of the chuck and break 3 layers of safety glass .