Q: I would like to try biscuit joinery but I do not own a biscuit joiner. Is it feasible to use a router to make the slots?
A: A router with a 5/32-in. slot cutter will work fine for making an occasional biscuit joint. You can alter the slot depth to accommodate No. 0, No. 10 and No. 20 biscuits by using different router bits or by changing bearings.
To cut a biscuit slot with a router, you generally need to make the initial plunge cut and then move the router approximately 1/2 in. left and right of center. It’s best to eyeball a couple tick marks 1/2 in. to either side of your biscuit layout mark. With the router running, push the bit in at the left-hand tick mark and slide it to the right-hand tick mark. The resulting slot has a different shape (see photo, right) but the same joint-holding strength as one made with a biscuit joiner.
Biscuit joiners do have an advantage when it comes to simplicity and range of possible joints. With a router, it’s hard to slot bevels or execute a T joint—although it can be done with 5/32-in. straight cutter and a fence.