You can sand until you end up with a toothpick, and still not remove the lignin ( the substance that bonds the wood fibers together ) that was melted when the factory checkering was applied.
I was successful, however, in converting the factory negative/impressed checkering to positive checkering diamond via running a single row checkering tool (head) up/down/across the rows with the tool cutting out the ridges between the depressions, leaving the high spots ( at each X ) as the tips of the checkering diamonds.
If you attempt it, though, cut the partitions between the depressions with a razor knife before running the checkering down the rows.
The photo below shows Negative Impressed checkering with the upper left portion converted to Cut checkering
http://sparetimeactivities.net/photos/StockCheck05.jpg
The photo below shows Positive Impressed checkering with the right portion converted to Cut checkering
http://sparetimeactivities.net/photos/StockCheck04.jpg
The photo below is of Negative Impressed checkering converted to Cut checkering
http://sparetimeactivities.net/photos/StockCheck10.jpg
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