Q & A: Use a Router for Biscuit Joinery

PWE150301_QA

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.

Many manufacturers offer biscuit joining bits. Some use a single 5/32-in. slot cutter plus different sizes of bearings for different biscuit sizes. Others offer three separate bits for each biscuit. The MLCS system shown above uses three different bits. A specialized round biscuit fits the midsize bit without the need to elongate the slot. It’s perfect for joining face-frame stock and can be used on rails as narrow as 1-1/2 in.

Many manufacturers offer biscuit joining bits. Some use a single 5/32-in. slot cutter plus different sizes of bearings for different biscuit sizes. Others offer three separate bits for each biscuit. The MLCS system shown above uses three different bits. A specialized round biscuit fits the midsize bit without the need to elongate the slot. It’s perfect for joining face-frame stock and can be used on rails as narrow as 1-1/2 in. Click image to enlarge.

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.

One thought on “Q & A: Use a Router for Biscuit Joinery

  1. rbtpartsman

    I use my router for biscuit joinery all the time. By using it so often, it goes very quickly and smooth. I just haven’t been able to justify buying a biscuit joiner when I only use biscuits for straight edge joinery anyway. I suppose if I ever find one on sale at the right price and I have the extra money at that time I may purchase one, but right now there are more important tools to buy first. (like my new Craftsman compact 10″ sliding compound miter saw I just purchased to replace my old Delta 10″ compound miter saw that didn’t slide.)

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