Hard Turning with no Feed Marks

To All:
I missed this when it first came out, but here is a way to hard-turn
bearing & seal OD's and the like. Here are some excerpts from an
article in MMSonline (short video at site).
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Hard turning can reduce, and in some cases eliminate, finish grinding
operations. Because it is a single-point turning process, however, it
will produce feed marks on a part?s surface no matter how much the feed
rate is reduced.
Sumitomo Electric (Mount Prospect, Illinois) has developed a
"lead-free" tooling system...
The keys to this lead-free turning process are tool design and feed
direction. Single point turning feeds a cutting point along the lathe?s
Z axis?longitudinally down the rotating part. Conversely, lead-free
turning moves a wide, blade-like insert tangentially across the part in
the X axis. A dedicated toolholder provides the proper lead angle for
the insert as it traverses across the workpiece.
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I have a 6 gallon crock I been putting this kind of shit into for nearly 3 decades now.
Obviously it still leaks
Reply to
Brother Lightfoot
You saw the video? It looked like a pretty slick idea to me. Have you ever tried it?
Reply to
That's pretty interesting. FWIW, I have a book here from the 1930s that shows a tangential cutter (made of HSS) that has the same purpose. But this one is fed conventionally in the Z axis, rather than plunged.
Reply to
Ed Huntress
BottleBob wrote in news:yNSdnZfEDO5rYZzWnZ2dnUVZ snipped-for-privacy@earthlink.com:
It's also called "Skiving" Bob. Been doing it for decades in cast iron grooving operations.
Reply to
Anybody who's ever spent any time around automatics will recognize this as just a new twist on a VERY old technique call a shave tool. New materials and machines make it possible to do this with hard stock instead of just 12L; but a traditional shave could do profiles, gooves, spherical OD's, and then some.
And, properly used, it would let you hold sub-one-thousandth tolerances on machines that couldn't position within +/-.005.
Everything old is new again.
Reply to
Kirk Gordon
You know, the jargon of machining has changed all around over the years, but a skiving tool used to be a form tool that worked with no top rake and, often, with no relief. It was just plunged into the work slightly below center, which gave you a negative effective rake and, effectively, it allowed a bit of front clearance below the cutting edge.
This tool looks more like a shaving cutter, although the geometry of just plunging it into the work looks a little weird to me. The shaving cutters I've seen generally travel along the length of the work.
Reply to
Ed Huntress
Yep, Even on one my old Davenport's I could hold tolerances like that.
Reply to
Exactly what I was going to say Anthony but thought it might have been a UK term not used in the US. Well it is in the "Slacking Off" meaning! Does seem though that it's a term that will create puzzled looks these days.
My late mentor used to use the process a lot for fairly complex forms.
Reply to
Wayne Weedon

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