Ten-Cent Solution for Hollow-Chisel Woes

An inexpensive fix for a screaming mortiser.

By Michael Pekovich #219–May/June 2011 Issue

**Set it, raise it, and square it.** First, set the hollow chisel at the correct clearance using a dime.

If your hollow-chisel mortiser screeches when you turn it on and clogs and burns when you mortise, there’s a simple solution. The problem is that your auger bit must have little or no room to turn within the hollow chisel. The bit is fatter at its tip and needs to stick out from the end of the chisel a little. To set this clearance properly, I use the “dime trick”: Simply install the chisel with a dime between the chisel and mortiser and tighten it in place. Then, using a scrap as a pad, push the bit up until it is seated against the chisel and tighten it. Finally, loosen the chisel and push it up as far as it goes—the space where the dime used to be will create the necessary clearance. While you’re at it, put a square against the fence to ensure that the chisel is properly aligned.

Then raise the auger bit up firmly into the chisel and tighten it.

Finally, reset the chisel by raising it fully and simultaneously squaring it to the mortiser fence.

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