Use a lighter pressure against the paper than you
normally do on the belt and slow down the movement
across the face of the wheel, say 4-5 seconds from
just short of the should to the blade tip, slow
down even more with the 800 and 1200 grit papers.
Your procedure should be as follows:- take 2 to
3 passes across the wheel, cool the blade in your
soapy water, have your air gun close at hand and
blast both sides of the blade to dry it and once
across the fact of the wheel to remove all grinding
dust. This way you do not contaminate the blade
or paper with larger particles of dust you may pick
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on cloths/brushes
etc. repeat this procedure every time you cool the
blade.
NOTE: all machine sanding is kept dry; your
wheel should run at +- 950 r.p.m. however the trend
to day is to increase the speed with the 800 and
again the 1200 grit papers for an even finer finish
- so experiment. Do not move on to the next grade
of paper until all the previous grade scratch pattern
has been removed and you have lightly sanded over
the shoulder on the edge of the wheel. A 350mm diameter
contact wheel can normally complete two blades of
approximately this size on each grit size. On a
250mm diameter wheel I change the paper after each
blade. |
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What I recommend you do if this system works for
you is buy or make yourself at least 3 smooth contact
wheels 3-5mm larger in diameter than the wheel you
normally grind on - for this finishing system. A
notched wheel run at these low revolutions serves
no benefit at all and does not sand as efficiently
with the paper stuck to it as a smooth one would,
(i.e. you are not making use of the paper over the
notches.) I opted to make my own wooden wheels 16
years ago and they are still operating perfectly.
It appears the only thing you may have to watch
out for is borer beetle, so keep them running. |
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These finishing wheels are constructed as follows:
They are made from "Superwood" which
is available in a range of thicknesses - in layman's
terms, it appears to be made of fine wood dust
pressed and glued together to form a soft absorbent
board that machines well, similar to Masonite/Hardboard.
To make them I used 3 layers of 16mm thick board
cut a little oversize and glued and clamped together
with "Alcolin" wood glue. They are then
accurately bored to take a metal bush to match
your shaft size and then turned to the required
diameter.
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If your machines
can't handle this size, I suggest you glue them
up and hand them over to a sympathetic engineering
shop in your area for accurate turning and boring
to size. Next give them at least 3 coats of "Nova"
polyurethane varnish which soaks into the wood and
hardens and seals the surface, the push fit metal
bushes are then glued in place.
A strip of "Neoprene" Insertion rubber
(normally brick red in colour 4 to 8mm thick) cut
slightly oversize (in length & width) is needed
for the surface of the wheel - available from "Gasket"
type businesses. This rubber is the right density
and is impervious to solvents like thinners, etc.
you will end up cleaning the wheel with.
Sand the inside face of the rubber with a medium
grade paper, clean with thinners, coat the rubber
and the face of the wheel with a good contact adhesive
and leave until touch dry.
Lay the rubber flat (glue side up) and gently roll
the wheel along the rubber - to avoid stretching
it. Trim off the excess so the two edges butt together
and use superglue to stick them together, now firmly
press down the rubber and leave to cure. Run the
wheel on your machine and carefully sand the face
of your wheel square and flat with 120 grit paper
stuck to a heavy metal plate, supported on your
rest - true up the sides of the rubber the same
way to line up with the sides of the wheel, do not
round the edges.
If you're making one you may as well make 3, you
can probably make 20 for the price of one aluminum
contact wheels today.
Having a wheel available for each grit size you
will be using comes in very handy for many tasks
not to mention sanding the butt and top edges of
your knife once the handle has to be fitted.
This system should leave you with good definition
on your grind lines as opposed to heavy hand sanding
and once set up it goes surprisingly quickly, your
knife can be left at 1200 grit for a fine vertical
satin which look good particularly on double ground
blades.
If your intention is to horizontally satin your
blade move straight on to a 1200/1500 grit paper. |
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Now over to the buff. A good mirror polished finish
depends on how finely the blade has been sanded
and the amount of buffing required to get there,
there are compounds available which will remove
relatively deep scratches but they do so only by
sacrificing the overall blade finish and definition.
I start off on a 150mm dia. Narrow stitched mop
at 2850 r.p.m. and us "Rebuff" pre-finish
compound (light blue bar). Cut a small piece of
compound and hold it in your supporting hand, buff
extremely lightly and apply compound every 5-8 seconds,
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work in small areas and
keep the knife moving at all times. Inspect closely,
once all the sanding scratch pattern has been removed
(the compound leaves the blade with a fine mirror
like sheen) move on to the next step.
Change to a 150 mm dia. narrow reflex soft mop and
use "Reef Chemicals" compound number "RCClSDDB"
(white in colour) lightly buff as before to bring
to a bright mirror polish.
Points to
ponder: -
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Narrow mops make working on
small areas of the blade easier and don't
build up much friction. |
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"Buff lightly" means
try and touch only the compound and not the
mop. |
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If you're working on a stubborn
area, don't increase pressure but rather apply
compound more frequently, say 2-3 seconds. |
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Gently clean your mops with
a small steel brush (the once sold at hardware
stores for use on your hand-drill are ideal)
do this at least before starting and before
finishing, and blast over with compressed
air. |
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If a deep scratch appears that
you missed, go back to the finishing wheel
(easier said than done). |
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Mops run dry i.e. no compound
do nothing but ruin the finish by building
up heat. |
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Use only greaseless compounds
as these reduce friction and heat build up. |
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Keep your blade moving constantly
when in contact with the buff. |
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Store all pre-finish and finishing
mops and compounds etc. separately in dust
free containers. |
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Always have a good strong light
at your buff. |
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Buff at a 45 degree angle across
your scratch pattern where possible. |
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Buff from the center of your
blade down towards the cutting edge and down
towards your grind lines (never over). |
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Buff the ricasso and top flats
down towards the shoulder and down towards
the grind line. |
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The final touch on the buff
can lightly be run down the length of the
blade. |
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Mirror, mirror on my knife was it worth the trouble
and strife? You'd better believe it!
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