Rob Brown Custom Knives
Tapering Tangs
Rob discusses his technique.
 
Fitting Guards
Rob reveals the secret to a clean fit.
 
Fitting Bolsters
Rob discusses the method used for his curved bolster design.
 
Mirror Finishing
Rob has become known for his mirror polish - here's how it is done.
 
 
Mirror Finishing by Rob Brown
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Image 16
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 up
 
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.
Image 17
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.
 

Image 18
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.

 
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.
Image 19
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,
 
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: -

Narrow mops make working on small areas of the blade easier and don't build up much friction.
"Buff lightly" means try and touch only the compound and not the mop.
If you're working on a stubborn area, don't increase pressure but rather apply compound more frequently, say 2-3 seconds.
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.
If a deep scratch appears that you missed, go back to the finishing wheel (easier said than done).
Mops run dry i.e. no compound do nothing but ruin the finish by building up heat.
Use only greaseless compounds as these reduce friction and heat build up.
Keep your blade moving constantly when in contact with the buff.
Store all pre-finish and finishing mops and compounds etc. separately in dust free containers.
Always have a good strong light at your buff.
Buff at a 45 degree angle across your scratch pattern where possible.
Buff from the center of your blade down towards the cutting edge and down towards your grind lines (never over).
Buff the ricasso and top flats down towards the shoulder and down towards the grind line.
The final touch on the buff can lightly be run down the length of the blade.
Image 20
Mirror, mirror on my knife was it worth the trouble and strife? You'd better believe it!
 
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Copyright © 2001 - Rob Brown
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