Lathe Turning ??

[RIRR]

I have a 9" Southbend Lathe that I am starting to use. I was wondering what height you should set the carbide tooling at when turning steel?( usuing old 3/4" rivits that are non hardened). It seems to chatter and leave burrs. Also how high to set the cut off tool when finished to cut it to length? thanks

[John G. Simpson]

RIRR
normal practice is to set the tool at center or a few thousands low, above center will result in chatter and rubbing on end of the tool ( not good).
too low spindle speed with carbide will also result in a poor finish.
parting tools need to be very rigid for cutting and lots of oil.
have fun with your new toy.
john

[George Andreasen]

Carbide is a high production tool alloy requiring a fairly high turning speed to work satisfactorily. It is normally set at dead center on the work piece and should be horizontal in the tool holder, so the old "lantern" style tool post found on the older lathes isn't the best. Tip: to quickly set any lathe tool, place a small 6" steel rule against the work and move the tool tip up against the rule so it pinches it against the work piece. If the tool is truly on center the rule will be straight up and down. If not it will lean one way or the other showing what correction is necessary.
High speed steel tools (HSS) are normally set slightly above center. They are also inexpensive compared to carbide, so why not try them? I tried carbide in my South Bend 9" and the results were like you describe...I think because the lathe would not turn fast enough to take advantage of the carbide. It does work well in my modern lathe though.

[K D Redd]

You also need the right grade of carbide for steel. I think C6 is for steel C4 for cast iron and aluminum. I have a Chaftsman/Atlas that I use carbide in all the time. The form in which the tool is sharpened is important. You will needs a special wheel to sharpen carbide. Green or white colored stones. They are expensive. If you get a wheel to sharpen you carbides, DO NOT cool the carbide in water after sharpening. You can cause it to crack.

Kent

[StevenG]

When grinding Tungston carbide, one or two things should be done to get full advantage. Owing to the brittle nature of the material, the grinding must always be on the tool edge, never away from it, & to maintain correct angles it is usually advisable to grind on the side of the wheel, not on the periphery at the front where the curvature of the wheel will weaken the angles on the tool been ground. The tool, either HSS or tungston should then be finished by hand to get the best results, by putting a small radious around the front cutting edge with an oil stone.

[RIRR]

Thanks Alot guys for all the great info.

[Tanner Remillard]

I found good results with the basic cemented carbide turning tools. I take light, heavy, fast or slow speed cuts, and it usually leaves a nice finish any way I do it. The indexable inserts seem to be the ones that you have to run faster and take heavy cuts with to get a decent finish, but they are great for taking alot of material off in a hurry.