Using Biscuits - what size to use.

[Dan Mages]

Alrighty! Another ignorant newbie question.

I am new to using biscuit jointers, and I am wondering how I choose which size biscuit for the job. Is there any set rule, or is just larger biscuits for larger glue-ups?

Dan

[Eric Apple - Central IN]

It's easy... the biggest one that will fit

[Byron Trantham]

I don't know what the rules are; but I use the largest one that will fit the joint.

[Steve Clardy]

I don't know what the rules are; but I use the largest one that will fit the joint.

Me too. Largest one that will fit.
Steve

[Chris Padilla]

#20 is most common and therefore the one I use most but if you believe that biscuits are only good for alignment purposes and not structural, then it doesn't really matter what size you use.

[Daniel Rabinovitz]

Dan
The question is simple and the answer is also simple - as the other fellows stated the biggest one possible.
But make yourself a cheater block of wood for each size.
So I have 3 blocks
Each has the length and depth of each size cut into it.
AND each block has pencil lines showing the limits of the edges of the cut and the center line of the cut.
Hope that makes sense. And they sure come in handy for figuring which size to use.
Daniel

[Donnie Raines]

Chris makes a great point. Most of what I have read(being that I have never performed any science "spermints" myself) is that biscuits do not provide any added strenght to a joint. Yet, I see Norm use them on mitred corners and the like for "added strenght". I ,too, go for the biggest biscuit when glueing up tops and the like.

Hmmmmm...kinda makes you think uh????

[Eric McMillan]

Biscuits don't add any strength for edge-to-edge joints. For mitred corners, where is it end-grain-to-end-grain they do.

Eric

[Chris Padilla]

Ah...excellent point, Eric! You should get a bonus pick in the free-drawing! Norm always likes to add extra cross-grain pieces in areas where you run into short-grain situations like the end of an arm of a chair, for example. Absolutely, it does strengthen that weak point in the wood.