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Interrupted lathe cuts -- Technique?

I'm using manual Sherline lathe and have never been comfortable with turning down rectangular stock. Now I need to turn to a round 3" of a 2" square piece of Fortal aluminum. This requires riser blocks all the way around on the Lathe (to clear the slide but decreasing stiffness) and work holding in a 3.1" independant 4 jaw chuck with jaws reversed. The grip area for the chuck in this configuration is quite small which adds to my discomfort (I will be using a tailstock center). Can someone give me some general or specific advice on such operations: Is this as hard on the equipment as it sounds and feels? Best tool to use -- HSS, braised carbide, inserts, normal rake, etc.? Speed, feed, cut, etc.? General advice or techniques?

Thanks in advance.

Greg

Reply to
Greg G
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Bandsaw away most of the waste to start with, maybe you won't need risers ..

GWE

Reply to
Grant Erwin

Grant had a good suggestion----but if you have no saw:

You'll enjoy the best success using HSS, with a generous chip breaker, forming positive rake. If you're not familiar with what I'm talking about, contact me on the side and I'll send you a pic or two of tools with chip breakers to give you an idea. Stay away from carbide on your machine------especially for something like this.

Interrupted cuts in aluminum aren't an issue, although on your light duty machine, you could have trouble. You'll likely be limited to depth of cut and feed rate, but, on a larger machine, it would be a piece of cake.

By all means, do use the center, which will prevent the part from shifting in your chuck. Don't expect it to help if you don't use the right approach. The back side of the piece in question should be faced enough to form a firm base, making contact appropriately with the chuck body, or the jaws, then the opposite end faced, then the center applied. If you can't center drill, face the part after pressing it well in the chuck, then apply a small piece of stock that has been faced and center drilled, again, to prevent the part from shifting in your chuck. Make sure the part seats against something, otherwise you're wasting your time. You have to prevent the part from starting to move.

Does any of this help? More questions?

Harold

Reply to
Harold and Susan Vordos

Thanks Grant,

My finished diameter (1.97") will be greater than can swing over the slide so I can't avoid the risers . However, I will keep the suggestion in mind for future use as I hadn't thought of using my band saw that way -- only thought of milling.

Greg

Reply to
Greg G

Thanks Harold,

Will be sending you an email.

Greg

Reply to
Greg G

Saw off as much as you can or it will ruin the bearings. Soon after I bought my 6 inch Craftsman lathe I thought I could take a Briggs Stratton mower engine and convert it to a 2 stroke. I chopped off everything 4 stroke and went after it with various cutters, files and hope. Totally messed up the bearings but the end result was not bad. I put new Timkens in there. Good as new.

Reply to
daniel peterman

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