Hi everyone,
I’m a newbie on the woodworking scene, but am attempting my first project right now. It’s a cabinet that I am building to cover up some ugly exposed pipes in the utility room in my house.
I’m using biscuit joints to create the frame, and I’ve just cut my first slots and tried to dry-fit the biscuits. My question is this … should a biscuit fit into a slot to exactly half the depth of the biscuit when dry-fitting the biscuit? I know I’m using the correct depth of cut setting on my biscuit jointer for the biscuits I am using (#10), but on neither piece of wood does the biscuit go in to half its depth. When I try to dry fit the two pieces of wood together, they just about meet (there is approx 1mm of a gap). Once I’ve glued and clamped the joint, will this gap be eliminated?
Sorry if this is a silly question, but as I say, I’m new here!
Rob.
Replies
Sometimes the biscuits can expand due to humidity. If the joiner is set up properly like you say, try microwaving a few biscuits for a minute or so and dry fit them again. This may not be your problem but it helped me when using some 3 year old biscuits last August.
Good luck
Bob
Hi Rob, Most of the tools have a little thumb screw for fine tuning the depth on the end of the same threads where you choose which size biscuit you have chosen. If you can back it off a little (counter clockwise) and try it again you should be able to find the right amount.
Don't try to make it a perfect fit. It is a good idea to have a little space behind them.
It is a good idea to have a little space behind them.
Why do you say that? Won't that lead to a gap in the joint?
Instead, I'd increase the depth adjust a bit. It's OK to make the slots too deep, rather than too shallow.
Barry, I only use them for edge joining boards, and then, only for aligning the edges while clamping. If you do a good job of preparing the wood for the joint, and use the right glue, the glue-line is stronger than the wood around the joint. It doesn't need to be any better than that. I don't even bother with putting glue on the biscuits or in the slot. OK after writing the above, I re-read your post, and figured out that you and I are saying the same thing, I think. If the first statement is mine, I was saying cut the slot deeper than half a biscuit, so it does not hold the edge apart.Now back to the above. If you glue the biscuit, and fill the slot with glue, you can hydraulically force a lot glue into the grain around the joint, which will cause the wood to swell around the biscuits as well as having it yellowing the pores all around them on the face. If you finish sand while it is swollen, it will shrink later on, causing a shallow depression that can show up when you have the light right, and a low angle reflection.
I was saying cut the slot deeper than half a biscuit, so it does not hold the edge apart.
OK, I misunderstood what you were saying. Yes, I agree with that. The whole point of biscuits is that neither the slot depth, nor side-to-side placement, needs to be precise.
Thanks again guys, your help is much appreciated. The whole concept makes a lot more sense now.
Rob,
The way I check biscuit depth is to insert the biscuit into the slot all the way, then take a sharp pencil and scribe a line on the biscuit using the edge of the work piece as a guide for the pencil. Withdraw the biscuit, turn it around and insert the other edge into the slot. The pencil line should just disappear into the workpiece. Biscuits slots can be cut slightly too deep; the glued biscuits have such great holding power there is still plenty of adhesion. Just don't cut them too shallow and expect the clamps to draw them up tight.
To your ending question, there should be no gap between the 2 boards wehn they are dryfitted. Gary
Thanks for the fast replies everyone. They all sound like good things to try.
I don't know any other woodworkers in my area right now, so it's great to have a place like this to come and get some friendly advice!
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