On 17 Apr 2007 05:07:30 -0700, cad wrote:

JoeD,
I used PM-C1018ON Marshallcrat (C1018) Low Carbon Onsize Ground
Flat Stock to make my scraper bits.

This is the low end quality. But, in scraping,I never make pressure
cuts. They are light barely discernable when I do it other than
watching the obvious fluff that comes off of the bit. So I rarely get
the bit hot.

I won't say that the 1018 doesn't work for you, as it obviously is-
but the problem with that material isn't a matter of whether or not
you get it hot, it's the lack of carbon. Low carbon means two things,
as I understand it. The first is that it is more malleable, which is
a point in it's favor, and the second is that it is not hardenable-
which is a big strike against it as a cutting tool.

Try one of these guys out, if you get the opportunity-

http://www.littlemachineshop.com/pro...y=120824224 6

You just grind the profile you need and away you go. They should be
heat-treated already. Couldn't tell you anything much about the site
these are on, it was just the first one I found. They do come in
different sizes, and should fit into even a very tight budget.

On my scraper bits I gring one end with a radius point, probably about
a 1/8th radius. The opposite end ground to a 1/2" radius for the
actual finish scraping. I have a hole in the middle of the bit. When I
need to remove heavy cut lines I use the 1/8" end. Then when I am
ready to impart a smooth wall I reverse the bit 180 degrees and take
light passes. A two in one bit.

You can get better steel, A2, that will hold an edge longer, but with
the proper releif angle on the scraper bit it does a fine job for a
long time.