I got a piece of custom 3/8 inch glass that fits 12 1/3 sheets of 11x9"
sandpaper - 6 per side.
The scale I have been using is:
I chose the scale based on the assumption that the grits appear (to me
at least) to run somewhat logarithmically.
I stopped at 3000 since it seems hard/expensive to find finer grits and
its not clear you gain much beyond that.
I started at 120 because based on my limited experience that seems like
the coarsest one would want to go without totally chewing up the metal.
Any comments or suggestiong for improvement on the above approach?
I am open to changing the grit scale to other common sizes if mine seems
I did a similar trick with 3 separate pieces of 1/2 glass using 1/2
sheets. Works great for me.
My grit schedule goes:
My schehule is based more on what I had laying around. Note the gap
between 600 - 1000 grit, because I can't for the life of me find 800
CAMI wet-dry paper. Note that grit sizes that start with a "P" (i.e.
P800) are a different scale that CAMI. I'll post a comparison chart
over on abpw
I've NEVER used the 100, very rarely the 150. Most chisels and plane
blades I start at 320. Once it gets past 400-500, it only takes a few
mins on the higher grits. You can get the 2500 and 3000 grits at auto
body supply shops. If I want to go past 2500 I switch to the
I've not used water yet, but I'm planning to as soon as I figure out
an way to keep my bench clean.
I seem to have found 800 at the same places that stock the rest of the
series so I have always assumed the scale was the same since the
products were listed together. Can you explain what I may be missing here?
I have been able to find the silicon carbide up to 3000 from the same
suppliers as the lower grits.
What is the advantage of microfilms over silicon carbide other than that
they seem to go up to much higher grits (10 or 20 thousand)?
They seem to be more than 10X expensive though...
What would be the advantage of water over dry sanding?
Does swirling around the grit do a better job of making the scratches
uniform and/or polishing than dry sanding?
Would oil (e.g., light machine oil or even WD40) be better or worse than water?
Here's my take on this aspect of sanding/sharpening: a liquid lubricant
is a good thing here, as it tends to "float" the sanding swarf and
reduces the possibility of clumping and clogging.
Years ago I had a partner in a woodworking enterprise who was an
absolute fanatic about sharpening. He *insisted* that one should never
use any liquid when sharpening, because it creates a slurry that would
round off the edge of the thing being sharpened.
Now as then, I dismiss this as mostly bullshit. Whatever ill effects of
using water or oil are more than compensated for by the benefits. And
just intuitively, I seem to get better results sharpening with a
lubricant than without.
You were wrong, and I'm man enough to admit it.
Title corrected. There is no "e" in ScarySharp(tm), guys.
On Mon, 5 Apr 2010 08:45:53 +0100, the infamous "Jeff Gorman"
That's classic, Jeff. Your own website gives a 404 error from your
http://www.amgron.clara.net/honingfluids77.html was what you were
after, isn't it? The end of your link was to "page77.html" for some
I've always done sharpening dry and am happy with the result. I both
blow and wipe off any swarf during blade checks as I sharpen.
Works for me.
In order that people may be happy in their work, these three things are
needed: They must be fit for it. They must not do too much of it. And
they must have a sense of success in it.
-- John Ruskin, Pre-Raphaelitism, 1850
If I understand your system, you are grouping six different grit
papers on the same piece of float glass. This seems to me an
invitation to allow coarser grits to cross over onto the next finer
grit. When I was grinding and polishing a telecope mirror we were
instructed to clean up completely after each size grit so as not to
contaminate the next finer grit. This mirror polishing may have a
lesson here for tool sharpening.
I personally wouldn't bother with any of these. Why? Because they are
pretty much polishing, not sharpening.
YMMV but I would rather spend my time making stuff than going through a
*dozen* - 12, count'em, 12 - grits for a bunch of tools to make a nice
shiny edge that is going to start dulling the instant I start using it.
Here's an idea I heard about. If you have a bunch of old hard drives lying
abut, and who doesn't? take them apart, glue a series of higher-grit to the
drive surfaces, then set up the power through a series of switches and tie
'em all down. So now you have all the grits, in order, spinning at easy
12,000 rpm. Sharpening to scary can be just that fast! And cool, if you add
in a bunch of unnecessary but cool geek-ware light blue lights etc.
I'm going to try it in about 3 weeks, I work in IT, and the one thing we
have in abundance is old hard drives to recycle. I heard another use for old
drives;, as source metal to build a Dave Gingery workshop. All that
I would doubt that would work - while the drives spin fast (and most are
7500 or maybe 10000 but few are higher than that), they have very, very
little torque. In fact, the only resistance the plattens face is air
resistance since even the heads rest on a cushion of air.
So good luck sharpening anything other than a micro/nano chisel at best
If you all you needed was a small DC motor to sharpen, why would anybody
be using multi-amp grinding machines?
For a typical edge, grind at 20 - 25 degrees (exact angle
doesn't matter) and hone a 30 - 35 degree microbevel with
the finest grit you have. Strop or buff to take off the wire
edge, and you're done. I love sharp edges, but I have
other things to do with my time.
Most of the work is polishing the back face to a
mirror finish prior to the first sharpening. It's nothing
to maintain the finish, just don't use the tool as a
brick chisel and don't hit it with a coarser grit
paper / stone except to repair damage.
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