I ordered a Porter Cable biscuit jointer and was wondering what size biscuits to order. How do you determine what size biscuit is used for a particular job. I have read about PC’s FF size but am still confused. Your advice is appreciated.
Submitted by HHolmesAnswer:
The three common biscuit sizes are 0, 10, and 20. You can find these almost anywhere, from home centers to specialty stores. While biscuits are a great joinery solution, they do have a few limitations. One is the length of the slot required to use a biscuit. Even the smallest biscuit, the 0, requires a slot that’s too long to use on the end grain of a 1-1/2″ wide face frame rail. This problem is solved by the FF biscuits. They’re round, instead of football shaped, and require a different cutter. Biscuit joiners typically use a 5″ diameter cutting blade. Some machines, like the Porter Cable 557, allow you to swap to a smaller diameter blade and use the FF biscuits. If your machine doesn’t allow the change to a smaller blade, you can’t use the FF biscuits.
When choosing what biscuit to use, go with the largest biscuit that will work for your application.
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Thanks Paul toward my biscuit jointer question. My jointer does the different sizes, 0, 10, 20 but it’s th thickness I an concerned with. My jointer seems to cut thicker then my bicuts are. Comments? Are there thicker biscuits?
Hi Kevin. All of the biscuits that you listed are based on the same standard thickness. That said, I have found huge variability in the thickness of biscuits. This is due in part to different manufacturing tolerances, as well as seasonable humidity variations that can dramatically change the fit of the biscuits in the slot. Generally what I’ve found is that when biscuits are loose, they still swell up and fit snugly in the slot after they have absorbed some glue. You can test this by soaking one in water and testing the fit.
In spite of all of the variability of fit, I have never had a problem with biscuits. That’s not to say that it wouldn’t be possible to have a problem, but I’ve had good luck in my 25 years of biscuit joinery.
Woodworkers Guild of America
I need 1/2x1inch biscuits
I recently picked up a used biscuit joiner. When I make a practice cut the physical width of the opening measures .230″. What size biscuit do I need for this opening?
Most biscuit joiners allow for an adjustment to be made to the depth of cut in order to allow the use of multiple sized biscuits; #0, #10, and #20. All of these biscuits are the same thickness. If yours supports only one size I’d suggest consulting with the manufacturer or the manual to know the biscuit size. #20 is the most commonly used size.
Woodworkers Guild of America
Can 10 biscuits be used for a 20 sized cut?
Hi Zach. It would not be recommended because there wouldn’t be much biscuit protruding from the slot after you slipped it into the first side, but if the biscuit protrudes at all (which I think it should) it might provide some aid in aligning the joint, so perhaps some slight value.
Rockler makes a handy gauge that shows exactly where the slot will be cut for the 0, 10, and 20 size biscuits.
A standard biscuit blade is not 5″; it is 4″ x 5/32″ which is an approximation of the metric size 100 mm x 4 mm. The arbor is 22 mm or 7/8″.