Thanks for the added info. I'm pleased to find carbide more
suitable for platinum; I can try that. When I've talked with
GRS before their offerings of the cobalt and carbide were
limited to just a couple or three shapes.
All I’ve ever bought from them, in Carbide, and perhaps all they
carry, is 1/8 inch square. From that, flat and diamond point
shapes are simple. for other shapes, you need to do some more
grinding. But since Carbide gravers (and note, this is tungston
carbide. it’s NOT a steel, and diamond tools are the only
practical materials for grinding or sharpening or polishing the
stuff) need a sturdier cutting angle than do steel tools (because
the carbide is quite brittle, a sharper cutting angle will chip
off), just a 10 or 15 degree or so belly angle makes it possible
to grind almost any face shape you might want onto that square
stock.
I have and use a gravermax,but I still use hand method for
most of my bright cut and pave'. Have you a source for
traditional style gravers in these improved steels?
As noted above, Tungston Carbide is not available as premade
graver shapes. Generally what you are buying is the stock tool
and die people would make various cutters out of. Round and
square stock. You grind at a slight angle into one end of it to
form a face shape as you desire, thus also building in the
beginnings of a belly on the graver. Face angles should then
also be about 70 degrees or so. The cutting angle at the cutting
edge will be only a little less than a right angle. But Carbide
takes an edge that will allow this to give you wonderful bright
cuts. GRS sells a video on the use of their sharpening fixture
that also discusses the way to grind these tools from this
square stock.
I have an extra suitable can opener motor that I was going
to set up with a fine diamond lap; the ceramic lap sounds
better.I have a xxx fine ruby stone that I use for fine work.
It's a stretch from 600 grit. What diamond spray do you use or
suggest?
Use a 600 grit diamond for final shaping. You could use
coarser, if you have it, for roughing in, but it’s not needed.
You need the ceramic lap with diamond compound to polish carbide.
A ruby stone, used with diamond compound, would also work. But
the carbide is harder than the ruby stone itself, so you have to
have that diamond compound. 14 thousand will put a decent
bright polish on a graver. You can use 50 thousand if you like.
Very slightly better polish, but slower, and maybe not worth the
additional slight degree of brightness.
The oil is a great tip. I haven't experienced any rust but
oil sounds like a potential improvement. I'm glad you didn't
suggest wintergreen.
wintergreen is a good cutting lube for when your graver is
cutting the silver or gold etc. It’s not such a good cutting
lube for when you are actually grinding or polishing the graver
itself.
While your post wasn't meant as a graver clinic, I'm
compelled to add for the benefit of all, a few lines about
gravers. When you set them up sand and smooth the immediate
areas that will cut the metal. Then use crocus paper and lap
them(except flats) on your polisher with some black tripoli
To each his own, I guess. When the folks at GIA, in their
setting class, taught us to sharpen a bright cut steel graver,
after sharpening on a stone, we were taught to use a piece of 4/0
polishing paper on a smooth surface like glass. With that, we’d
take one stroke absolutely parallel to the cutting edge, so these
finest of scratches ran exactly parallel to the cutting edge.
Actually, it was two strokes, One in each direction, so you’d
reach both outside edges of the cutting edge, and you’d do this
to both top and bottom (belly and face) of the graver. More than
those four careful strokes, and you start to round over the
cutting angles, and your graver stops being so razer sharp.
This has also, in my experience, been the problem with using
various tripolies and rouges. The cutting edge LOOKS brighter,
but the graver isn’t actually as sharp, as the edge gets honed
rounder. The key is that if the fine scratches run exactly in
the same direction as the cutting edge, then the scratches don’t
ever actually intersect the edge. If they do, such as if you
stroke it either “off” or “onto” the cutting edge, then
microscopically, the edge now looks like a sawtooth, as the
scratches cross the sharp edge. That gives you a duller cut.
I’ve found, with steel gravers, that the brightest cut I could
get was with a graver carefully done this way. The fine ruby
stones, used the same way, give you a wickedly sharp and clean
cutting edge, but not as bright. So I use the ruby stones, then
finish lightly as above with the 4/0 paper.
But for carbide, none of this works. You MUST use the diamond
compound, and the size of this grit is so small, that it no
longer so much affects the final finish whether or not you go
across the edge or parallel to it. Going across the edge
eliminates the very slight tendancy to round the edge over than
you might get if you’ve got too much compound on the wheel, so
with the carbide gravers, I generally polish with the direction
of the wheel stroking “off” the cutting edge.
Hope this helps.
Peter Rowe