"Aussie" wrote in message
...
I'm trying to part off some 12mm (1/2") PVC rod and am hoping to not
have to face the resultant parts.
The sides of the cut are terrible, not smooth at all.
I'm using a HSS parting off tool similar to this:
http://www.assetplant.com/WebRoot/Store/Shops/shop/5512/2DE6/890C/F386/E667/C0A8/C83B/12E3/1-2.jpg
Any pointers on how I should sharpen the tool?
How important is finishing the tool with an oil stone after
grinding?
Should I have a dip/notch on the top face behind the cutting edge to
deflect the "chip"?
How critical is the speed?
Thanks.

Something is wrong but I can't tell what without examining all the
details of your setup, many things can cause problems.

When my 1/16" wide HSS cutoff blade stops behaving well, usually when
parting stainless, I hollow-grind the end to the curve of the wheel
and stone the cutting edge to feel sharp to my finger. My Multifix
tool holder gives the blade a 4 degree back rake angle. I stopped
grinding a chip breaker in the top surface because I can't make it as
smooth as the factory finish.

As for speed, if the blade chatters I reduce it until the cut quiets
down, typically at 300 RPM.

It cuts PVC water pipe very smoothly, enough to use it for turning to
final diameter.

-jsw