In using a Powermatic benchtop mortiser, please advise as to how to prevent tearout on a through mortise. This particular mortise is not centered in the 3/4 inch board of QSWO, but offset 1/8″. Is a 3/4 ” backing board the best way or punching through from both sides?
Thanks,
lostcreek
Replies
Lost:
Both approaches should work equally well. The backer board would ideally be exactly the same width and of course one spot couldn't be used twice. Working from both sides would require exact transfer of the end lines to the other side, and I seldom hit my pencil lines exactly the same each time.
You could also try chiseling from the back through the front that way the shoulders of the tenon piece would cover the exit hole and any chip out you may have had.
I have a converted drill press used as a hollow chisel mortiser. The sacrificial backer board works for me but you do have to keep moving it to a fresh spot. I use a low profile drill press vice to hold the workpiece.
Bret
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