Lee Valley Screw-Slot Bits

WOOD magazine rating
Lee Valley


Any large panel or table top should be secured in a way that allows it to expand or contract without splitting.

These screw-slot bits let you create screw slots so that panels can be held in place but are able to slide back and forth without splitting the wood or breaking the screw securing them.

Both have 1/2" shanks and are sized for #8 screws, one for countersunk screws and one for counterbored screws.

WOOD magazine review

Lee Valley router bits cut lots of screw slots

Review Summary

The typical method of forming expansion slots to allow for seasonal wood movement (drilling a row of holes and then using a file or chisel to remove the material between) offends my sense of craftsmanship, because the slots are always ragged. And when the screw heads must be recessed to allow clearance for, say, a drawer, you have to drill holes for an elongated counterbore, clean it up with a chisel, and then form the slot, centered in the counterbore. It’s a lot of mess.
Screw-Slot bits use your plunge router to create slots with a counterbore (model 16J11.70) or a countersink (model 16J11.60) in one smooth operation. Both 1/2"-shank bits fit #8 screws, and each is designed to work in maximum 3/4"-thick material. (You’ll get a 1/4"-deep counterbore when plunging through 3/4"-thick material.) I chucked one of the Screw-Slot bits into my router and set the plunge depth to 13/16". Guiding the router against a straightedge, I simply plunged the bit into the workpiece and moved it back and forth to form a screw slot. It cut quickly and smoothly without chatter. At first, I plunged the bit completely before moving it to form the length of the slot, but noticed burning at the entry. Working the router back and forth while gradually plunging eliminated burning, and it seemed to cut easier. Unlike an ordinary straight bit, Screw Slot bit tips are pointed for plunging. A flat washer under the head of a panhead screw seems to be the most foolproof method of ensuring bind-free movement. So for my money, I’d just get the counterbore bit. —Tested by Jan Svec

Detailed Ratings

out of 5





Ease of Use




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