Metric equivalent to CPMW32.51?

[WobblyHand]

Have some CPMW32.51 inserts for my Sherline fly cutter. Chipped one, clearly I wasn't paying attention enough. Like to get a few more. If I buy some more, then I won't break them very often. Kind of a Murphy's Law sort of thing.

Looking through eBay, I can find some labelled VC29 and VC919. From the pictures, I can't quite tell if they would be good. Is there a cross to it's metric equivalent?

The only marking on the insert itself is WKK20S 04/1 RK6 Using that as a search term only lead to confusion... I tried zimi-hk but they don't seem to have any CPMW inserts.

 

[RandyWilson]

The ANSI 32.51, which is really 3 2.5 1, equates to an ISO 09T304

 

[WobblyHand]

Umm, does that mean it's CPMW 09T304, or just plain ISO 09T304? CPMW09T304 is correct.

Surprisingly, I've looked over some of the naming standards, but unfortunately, it hasn't sunk into my stubborn brain yet!

CPMW doesn't seem to be that common.

 

[RandyWilson]

It would be CPMW09T304

The first four letters are the same. In this case a (C) 80 degree diamond with an (P) 11 degree rake, (M) xx tolerance, (W) with a hole and no chip breaker. 3/8th size, 2.5/8 (aka 3/16) thick, and 1/16 nose radius. The 09 T3 and 04 are just metric equivalents.

Two sites that I use most, but there ar emany others.

http://www.carbidedepot.com/formulas-insert-d.htm

http://www.qtstools.com/document_library/tech-resources/Turning/ISO-ANSI Insert Crossover.pdf

 

[RandyWilson]

Let me add that those cover shape, style, and size. The V29 you saw is likely material and or coating. Those numbers are all manufacturer specific.

The CPMW is a unusual one. The C is common. The P is not. M no matter. And the W is also uncommon. The closest common one would be a CCMT. Slightly less rake but has a chip breaker. The question is how precise the pocket in your tool is. Will it work with a7 degree insert rather than the 11?

 

[mikey]

I use the Valenite CPMW 32.51 VC29 inserts on my Sherline fly cutter. They have worked quite well and the inserts last a long time. VC29 is supposed to be a fine grained uncoated carbide suitable for finishing cuts. This is a flat topped insert without a chip breaker and based on my personal experience with it, I would jump. The ebay price on these is very good.

 

[WobblyHand]

Hmm, I was willing to try some CCMT inserts, but now I'm not so sure they would fit. It seems the pocket is machined to be close to 11 degrees. Here are the bottom and top views of the tool.

On the other hand, this tool doesn't look that hard to duplicate... Only hard part for me would be the pocket.
Details of the pocket.

I'm not seriously thinking about making a new fly cutter just yet. If I were, what kind of steel should I use? 4140 ok? Something else?

 

[WobblyHand]

I use the Valenite CPMW 32.51 VC29 inserts on my Sherline fly cutter. They have worked quite well and the inserts last a long time. VC29 is supposed to be a fine grained uncoated carbide suitable for finishing cuts. This is a flat topped insert without a chip breaker and based on my personal experience with it, I would jump. The ebay price on these is very good.

I was looking at those very ones, but wasn't sure if they were the correct ones. At $2.50 each, they are definitely worth a try! I've seen the same ones listed for $8.80 each, min buy quantity = 10. @mikey thanks for the enabling link.

 

[mikey]

I use the very same ones. I just looked in the drawer so I am sure.