1) Stoning is to be performed only on used gage blocks where the surface finish may be degraded by scratches or small nicks.
2) Make sure the stone is clean and dry--free from any dirt or abrasive compound. Abrasives on the stone may lap the block and significantly alter its size.
3) With a light amount of pressure, stroke the block across the serration two or three times. (Forward, back, and forward.) It is not recommended that more than light pressure be used unless necessary to remove nicks and burrs.
Rusted Gage Blocks
The condition of rusty blocks may be greatly improved by stoning the blocks after the stone has been wetted with kerosene. While this may temporarily improve the utility of the block, this will not permanently remove the corrosion or halt its advance.
1) Take a cotton swab and dampen it with kerosene.
2) Wipe the stone with the dampened swab. A film of kerosene should be seen on the stone, but the stone should not be dripping wet.
3) Stone as before, using whatever pressure is necessary. It may be necessary to be quite aggressive to remove the corrosion.
Stoning Pressures
Light Stoning: 1 – 1.5 lbs
Medium Stoning: 2.5 – 3.5 lbs
Heavy Stoning: > 6 lbs
4) If the corrosion cannot be removed after repeated tries, then the block is considered to be damaged.
5) Keep the stone dampened as the kerosene evaporates.