For precise
layouts on metal, I use a carbide scriber with rounded point. Carbide
scribers are readily available from a number of sources, and easily
modified to become the perfect scriber.
I prefer a slow taper to my scriber point, and regrind commercially
made scribers so I can easily see the tip as I'm drawing under the
microscope. After you've tapered to your liking, sharpen the scriber
to a fine, needle point on the Powerhone with a 260 grit diamond lap.
260 is sufficient for sharpening, but I usually take mine all the way
to 1200 for a super smooth finish, followed by polishing on a piece of
leather treated with diamond spray (I can then use the sides of the
scriber as a burnisher).
Next, very carefully round the
needle point on the ceramic lap. The rounded point can then be
polished on a piece of leather treated with diamond spray. Be careful
with the rounding of the point as it's very easy to remove too much
material. The object is to have a very sharp scriber with a small
radius tip, not a wide, rounded tip. Smaller points are easier to
see around under the scope, and allow extremely precise layouts.
BENEFITS: The rounded tip scriber will
allow you to draw in any direction on metal, much as you would with a
ballpoint pen. The scribed line is not scratched into the metal, but
lightly burnished. In my travels I can't tell you how many times a
student or visitor has watched me scribe a layout, and then pick up my
scriber and closely examine it with a bewildering look, and then ask
where they can buy one. Give it a try, and I'm sure you'll be pleased
with the results.
My friend
Jason Marchiafava makes his scribers from sewing machine needles as
above, and puts them into a mechanical pencil! When not in use, the
scriber slides back into the pencil for protection. He also uses the
side of the scriber as a burnisher. Thanks, Jason!
Speaking of precise
layouts, sharpening a 9H pencil to a needle point will result in
extremely fine lines, and the super-hard 9H will stay sharp longer
than softer lead pencils.
Spin
the pencil in your fingers as you sweep it across a piece of 320 or
400-grit sandpaper.
PROS: Razor sharp layout lines. Stays
sharp.
CONS: Best suited for drawing through layout material
such as beeswax & tallow, talcum, etc. Definitely too hard to draw on a compound such as Chinese white. Nearly impossible to
find as most companies seem to have stopped making them, but the
mechanical variety is available through drafting supply stores
MasterGraphics has lead holders and 9H leads.  |
