I like using a jig to cut the groove . Sets the stopping point for the corner and gives me better control . I have a 1 1/4 HP Bosch palm router ( love that thing ) for doing edges and the groove on Carving boards .
I set it up to work with that router , but you can buy adjustable ones . I just screw it to the bench .
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Helps to keep the corners from burning .
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I have another one that centers the finger grab and locates the feet equally .
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That cheese board came out nice . Got to watch that edge grain on maple . Runs different directions right in the middle of the board .