JessEm - Zip Slot Mortise Mill
The Zip Slot Mortise Mill lets you cut mortises with a special bit driven by any drill-corded or cordless.
Jessem Tool Company recently introduced a unique jig called the Zip Slot Mortise Mill that lets you cut mortises with a special bit driven by any drill-corded or cordless.
After clamping on a workpiece, you just slip the bit into a bearing-guided bushing that’s part of a sliding carriage. Then you start the drill and move the carriage back and forth while pushing the bit incrementally deeper with each pass. The jig is nicely machined and well made. Even after a lot of practice with the jig, however, it was easy to end up with slightly stepped side walls, evidence of each back-and-forth pass. That said, the variation was less than 0.005 in. total, and the mortises produced by the jig were generally better than I can drill and chop with a chisel.
The jig cuts mortises up to 3-3/8 in. long, located up to 1-7/8 in. from a board edge. The standard bit cuts a 3/8-in-wide mortise; accessory bit and bearing sets that cut 1/4-in.- and 1/2-in.-wide mortises are available. Changing from one set to another was quick and easy.