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Nov 30, 2022 - 03:27 AM
Q - How do you use these to lap stones correctly? I have never done this before and have seen several different methods to flatten stones and it's sort of overwhelming. Also, I understand that the powder must be coarser than the stone, but why shouldn't I use F1200 powder on my F1500 Venev? Thank you
A - Lapping is a term used commonly (and sometimes incorrectly) by people for flattening, dressing and conditioning. Some even incorrectly use the word lapping for cleaning stones. This in itself is part of why there is a lot of confusion. To simplify it, let's use the words flattening and conditioning. Flattening is self explanatory, and conditioning is refreshing the surface to help it perform as expected. Both will assist in exposing a fresh layer of stone abrasive.
You can flatten most bonded (resin, vitrified or other bonds) sharpening stones with very coarse grit abrasive powder, like the F60/F120. The coarser the powder used, the faster you flatten it. As a matter of interest, while using coarse silicon carbide powder, you'll also find it breaks down quickly and becomes a lot finer so you'll need to use new powder regularly. When you've flattened a fine grit Venev bonded stone (as an example) with a very coarse abrasive, it will only be very slightly more aggressive (not significantly) for a short while and then settle back into it's original state. This is normally only 1 or so sharpening sessions. If you don't want it to be slightly more aggressive immediately after flattening, then use a finer powder after you've used the coarse powder. Remember, the stone bond does not do the cutting when sharpening, the abrasive in the stone does. When you use a very coarse grit abrasive on a stone to flatten it, you're creating grooves with "valleys" and "hills" on the surface and the tops of the "hills" will temporarily cut metal more aggressively until they quickly wear away and the stone is back to normal. You can't physically and permanently change the grit of your venev or other bonded stone by flattening with a coarser abrasive than the stone itself. It will only temporarily be slightly more aggressive, so no need to be too concerned about it.
To flatten your stones, use a flat, hard surface (such as glass/ceramic tile/marble/granite etc) and sprinkle a couple pinches of silicon carbide on the area you want to use. Beware that the surface you're using will be scratched after use, so don't use your kitchen countertop or something. :-) Now spray some water over it to wet the surface you're using. Take your stone and draw a hatched cross pattern over the stone surface with a pencil. Now place the stone on the wet surface with abrasive powder and simply rub it in figure of 8 patterns over the abrasive surface. Rotate the stone every now and again to even out the surface pressure you might be applying so one part does not wear down faster. Continue until the pencil lines are gone and then rinse and wash the stone properly to remove all excess abrasive grit from the stone. If it's a fine stone and you want it to immediately perform as expected, then use a finer grit powder and repeat the process.
Hope this helps!
A - Lapping is a term used commonly (and sometimes incorrectly) by people for flattening, dressing and conditioning. Some even incorrectly use the word lapping for cleaning stones. This in itself is part of why there is a lot of confusion. To simplify it, let's use the words flattening and conditioning. Flattening is self explanatory, and conditioning is refreshing the surface to help it perform as expected. Both will assist in exposing a fresh layer of stone abrasive.
You can flatten most bonded (resin, vitrified or other bonds) sharpening stones with very coarse grit abrasive powder, like the F60/F120. The coarser the powder used, the faster you flatten it. As a matter of interest, while using coarse silicon carbide powder, you'll also find it breaks down quickly and becomes a lot finer so you'll need to use new powder regularly. When you've flattened a fine grit Venev bonded stone (as an example) with a very coarse abrasive, it will only be very slightly more aggressive (not significantly) for a short while and then settle back into it's original state. This is normally only 1 or so sharpening sessions. If you don't want it to be slightly more aggressive immediately after flattening, then use a finer powder after you've used the coarse powder. Remember, the stone bond does not do the cutting when sharpening, the abrasive in the stone does. When you use a very coarse grit abrasive on a stone to flatten it, you're creating grooves with "valleys" and "hills" on the surface and the tops of the "hills" will temporarily cut metal more aggressively until they quickly wear away and the stone is back to normal. You can't physically and permanently change the grit of your venev or other bonded stone by flattening with a coarser abrasive than the stone itself. It will only temporarily be slightly more aggressive, so no need to be too concerned about it.
To flatten your stones, use a flat, hard surface (such as glass/ceramic tile/marble/granite etc) and sprinkle a couple pinches of silicon carbide on the area you want to use. Beware that the surface you're using will be scratched after use, so don't use your kitchen countertop or something. :-) Now spray some water over it to wet the surface you're using. Take your stone and draw a hatched cross pattern over the stone surface with a pencil. Now place the stone on the wet surface with abrasive powder and simply rub it in figure of 8 patterns over the abrasive surface. Rotate the stone every now and again to even out the surface pressure you might be applying so one part does not wear down faster. Continue until the pencil lines are gone and then rinse and wash the stone properly to remove all excess abrasive grit from the stone. If it's a fine stone and you want it to immediately perform as expected, then use a finer grit powder and repeat the process.
Hope this helps!
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