Not sure if this post even goes here, but here goes.

I am doing some Vee engraving in vinyl for someone (or more specifically, recycled milk jug material, the stuff they make decks out of), but I'm not getting a clean cut.

I'm using a porter cable 7518 at 21,000 rpm, feed rate 60 ipm, with Whiteside bit 1541 (3 flute 60 deg).  I have a lot of flakes down in the grooving that won't come out.  Am I getting material re-welding due to friction?

Try this link http://www.plasticrouting.com from onsrud (they should pay me for this, but their tools really work)
You have a tool search there where you can search by material to cut.
If you have doubts, try 61-042 1 O flute straight
I tested it with HDPE, Nylon, Polypropylene, acrylic and policarbonate and it gives a clean edge finish

Thanks a lot, but I'm doing v engraving in 5/8 and 3/4 material...I'll have to keep looking and check that out!

Bill

Hi Bill,

This problem was discovered by engravers, many years ago.
The trouble is that the very tip (magnified) of a standard vee tool has no cutting edge therefor a great deal of friction is present which, with stuff like HDPE results in melting and subsequent poor finish. If you study the geometry of an engraving point, you will see that it has a flat on the point (only about 0.004" wide) and this flat has clearance which makes it into a cutting edge and therefore reduces friction.
Exactly where one can be purchased I don't know but there must be 'purpose made vee tools' which are made especially for plastics which probably look just like the standard engraving points.

Tweakie.

Thanks!

I will have to look into that.

Bill