Hard turning?

[scott-ak]

Truck transmission parts. I need to make the long one shorter. All I've got are average carbide inserts. Any guidance to keep from fubaring this part would be appreciated

 

[Cole2534]

Pick up some CBN inserts is my guidance.

 

[partsproduction]

Ceramic inserts, up to 60 Rc, not happy with interrupted cuts. 2000 FPM so the chip rises red and loops over turning darker before it hit's the lathe, around .010" max DOC and a fine feed, watch your insert nose, but they last quite a while.

Also, regular negative carbide inserts run around 100 FPM, still can't take deep cuts but still works under 50 Rc OK, of course the speed shouldn't make the light grayish blue.
I don't claim to know it all but these things seem to work well for me.

 

[EmanuelGoldstein]

Truck transmission parts. I need to make the long one shorter.

Just the cylindrical part at the top ? Should be a picnic. Tranny gears are normally carburized, use any old carbide, take off .050 or so on a side, and the core should be about 35 Rc. I usually nail it in one pass with negative rake. After that anything works.

 

[Orange Vise]

Just use carbide. Chances are you'll get through the whole job on one edge. Worst case two or three.

Carbide is plenty capable of hard turning. It's just not ideal for production applications.

 

[Cole2534]

Just use carbide. Chances are you'll get through the whole job on one edge. Worst case two or three.

Carbide is plenty capable of hard turning. It's just not ideal for production applications.

What sort of feed/speed should one start with?

Programmed via Mazatrol

 

[Orange Vise]

what sort of feed/speed should one start with?

Programmed via mazatrol

200 sfm, 0.004 ipr, .030 doc.

 

[Milland]

What machine and workholding? It's one thing on a good, rigid CNC lathe, another on a "hobby grade" tool.

 

[michiganbuck]

You are going to lose the center with turning, so why not just grind it shorter.

Turn the part between centers if it has centers, then grind off the stub

 

[scott-ak]

Carbide cut it just fine, it wasn't nearly as hard as I thot it would/should be. Recutting a taper to the internal spline was a pita.

Thanx