August 7, 2014 | 9:55 am CDT

My job as a technician for Dixon Abrasives is to make sanding make sense. This is not as simple a task as most people would think. Every part of the sanding process must work together to accomplish a few simple tasks.

Below is a chart that gives the maximum amount of stock a particular grit belt can remove and how much to remove to get to the bottom of the valleys. This should not be misconstrued as the scratch depth. Every time I tell someone the real scratch depth of a sanding belt they go about removing that much material with the next belt, never thinking about the fact they are removing way too much material and smashing the wood. Everyone measures off the top of the mountain peaks to the bottom of the part, not to the bottom of the valleys. So I never give scratch depth, only give the amount to remove from the mountain peak to touch the bottom of the valley.

Grit Max Minimum to remove

60 .035” .015”

80 .024” .008”

100 .017” .006”

120 .010” .004”

150 .006” .002”

180 .004” .001”

220 .002” .0005”

A quick example grit sequence would be 120, 150, 180. 120 grit can remove up to .010”. The scratch left behind requires the next belt to remove .004” to get rid of it. The 150 maxes out at .006”, but it only needs to remove .004”. The 150 leaves a scratch that requires .002” to remove. The 180 can remove up to .004”, but it should only remove the .002” required. This belt sequence can remove up to .016” maximum with good results. The final scratch requires .001” stock removal.

Another example: 100, 150, 180. 100 max is .017”. The 150 must remove .006” and the 180 must remove .002”, so the grit sequence can remove up to .025”. Final scratch requires .001” stock removal.

One more example: 80, 120, 180. 80 grit’s max is .024”. The 120 must remove .008”, and the 180 must remove .004”. The grit sequence can remove up to .036” with good results. The final scratch only requires .001” stock removal.

I am not going into how the design of the machine affects the ability of the machine to use these sequences. That is a different article.

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