Introduction to Indexable Tooling for the Metal Lathe

Perhaps we should take this off thread to a DM?
 
Here is another photo. This shows the holders and inserts from the underside. The experimental insert is on the right side.
View attachment 393234
The experimental insert DCGT overhangs the tool holder more than the Sherline insert DPMT. I think that the extra overhang is due to experimental insert having a smaller clearance angle: 7° versus 11°. The inserts are the same size (0.25-inch inscribed circle) on top and have the same thickness (3/32-inch). The smaller clearance angle gives the experimental insert a larger underside. I conclude that the experimental insert does not fit the tool holder well.
As I suspected, the Sherline indexable tooolholder is proprietary and doesn’t conform to industry specs. Good thing the test insert was $8.00. Now you know. Lets take this to another thread please.
 
Possibly you could start this thread in the Sherline section, so it's not lost to everyone?
 
I don't think that the result of the experiment means that the Sherline toolholder does not conform to industry specs. l I think that the result suggests that an insert with a smaller clearance angle will be large on a toolholder that is designed for an insert with a larger clearance angle. If that is correct, then the result is applicable generally.

If the DCGT insert had fit well on the Sherline holder intended for a DPMT insert, then I think that would have been good news to share on Sherline forums.
 
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Just received my copy today, and you can color me impressed; very informative book. Outstanding work, David!
 
Just received the book from Amazon, but it came damaged - some sticky packing tape on the front cover, impossible to remove. Amazon sending me a new one, and they don't want the first one back. I would gladly donate it to someone in need, just pay shipping. PM if interested.
Mike
 
So, I hope I can do this here and it doesn't come across as an advertisement. As many of you know, one of our members, David P Best, has been toiling over a book that he intends to publish. It is titled "Introduction to Indexable Tooling for the Metal Lathe: A User Guide Paperback" . He has completed it and it is available to order from Amazon. I know that David does very fine work, and I would anticipate that this book will be no less of an example of his capability.
I ordered mine last night. Should be here next week. Really looking forward to it.



Reason for Edit: Updated the Amazon link.
whatever you folks do plez STAY AWAY FROM SCAMAZON!!
 
The DCGT 21.5VFR-J10 J740 insert arrived. I installed it on the right handed tool holder, and used it to turn down 1144 steel and a bronze-aluminum bushing. Here are photos that compare the DCGT insert on the right-handed tool holder and the Sherline DPMT insert on the left-handed tool holder. In the photos, the left-handed tool holder is on the left.View attachment 393149
View attachment 393150
View attachment 393151

Note: I damaged the tip on the trial insert. The nose radius was 0.001 inch. The finish was poor during the finishing pass (2500 rpm spindle, 0.0003 inch / spindle revolution, 0.0005 depth of cut.) on two 1 1/8-inch diameter bronze-aluminum bushings.
Why so fast?

.0003 or .003?

You want to find a speed/feed that will cut well while leaving a hood finish on your machine.
 
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