Which biscuits to use and how many?

[Chris]

My oak plywood desktop is progressing. I've been trying to find more info on which and how many biscuits to use for the solid oak face molding. The top is 3/4" oak ply and the molding is 3/4" by 1x1/2" solid red oak. I will let the molding overhang the bottom of the countertop so I only have max 3/4" heigth and 3/4" deep to hold a biscuit. My friend told me to use FF biscuits and space them about

10" apart on a 10' span. Being inquisitive, I just wanted to know more about sizes, tolerances, spacing, quantity, etc.. Anyone have any good places to look and\or have any tips for my project?

Thanks,

Chris

[Doug Miller]

Your friend's advice is IMO under-engineered.

FF biscuits are for assembling a face frame: they are narrow enough that the biscuit slot will fit entirely within the width of a normal rail or stile. For attaching the face frame to a cabinet you should use larger biscuits such as a #10 or #20. (General rule is to use the largest biscuit that will fit, on the theory that the more surface area you have for glue, the better off you are.)

The manual for my biscuit joiner recommends intervals of approximately 6". Probably a 10" interval won't be a problem with a #20 biscuit, but I sure wouldn't space those teeny-tiny FF biscuits that far apart.

-- Regards, Doug Miller (alphageek-at-milmac-dot-com)

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[Preston Andreas]

I use #20 biscuits about 10" or so apart. When I glue the molding on, I put a thicker board between my clamp faces and the molding. That way, the clamping pressure is better spread across the molding and there is a tighter fit between the molding and the ply.

[Phisherman]

The 10" is about right. I use #20 biscuits for most things. Be careful about cutting the slots too close to the surface as the biscuits can swell and produce a small hump on your ply. Try to cut the slots along the center. Use clamps. A "dry run" can save a big headache; ie, put the facing on with biscuits and clamps without glue--that way everything will be within reach when you apply the glue without any surprises and reduces the chance of a panic attack.

[Edwin Pawlowski]

I agree with the others as far as spacing and #2 biscuits.

One tip though. Cutting the slots in the plywood is going to be easy as there is plenty of surface for the fence to sit on. Not so with the 3/4" trim.

Stack a couple of pieces together and clamp them. Now you have a wider surface and a more accurate cut for proper alignment. Use scrap if need be to get the thickness enough to offer good support to the fence. Ed [e-mail]

[patriarch]

"Edwin Pawlowski" wrote in news:Oqilc.13951$ [e-mail]:

So, Ed, you are suggesting registering using the fence to the edge of the trim piece? Why not register using the base against the benchtop or a bench hook? Seems to offer a more reliable means, with fewer things to adjust incorrectly, in my limited experience. And it puts the biscuit in the middle of 3/4 stock just fine, does it not?

This is not a major point of contention, by any means. Thanks for your many reasoned, thoughtful contributions to this, and other, USENET forums.

Patriarch

[Edwin Pawlowski]

"patriarch [e-mail]" So, Ed, you are suggesting registering using the fence to the edge of the

Do you have the plate joiner yet? If not, I can understand your question. They are designed to be used by registering the fence on the top of the wood and the cut is below. Like any tool, it must be checked for accuracy and adjusted if needed. Mine needed a minor adjustment of the scale.

OK, I have a DeWalt, others may differ slightly. Lets say I have a piece of 3/4' plywood.and want to center a biscuit. I set the scale to 3/8" (half of 3/4) and I'm ready.

Step one it so put the two pieces together and make a pencil mark where I want the biscuit to be when joined. Just a line across both pieces. I set the fence on the plywood, hold it firmly, squeeze the trigger and push in the make the cut. I can cut all along the wood and have the same spacing. Now I do the piece to be joined, again registering from the top, and I have a perfect alignment if I did my job correctly.

My particular tool is designed to be used that way. If I was to slide it on a table top or bench, it would not always be perfectly parallel. Why? The bottom of the tool is not flat and I can easily induce error. Without a trip to the shop, I have no idea what the scale from the bottom can even be set to. Why is the tool designed that way? Not every joint is made on the workbench. Let's say you are making a rectangular frame and you want to join the four pieces. The cuts will be on the edge for one piece but the face of the mate. Face is not easily done on a bench, nor may it be as accurate as registration with the fence from the top. Ed [e-mail]

[patriarch]

"Edwin Pawlowski" wrote in news:TFAlc.463$ [e-mail]:

I have the same tool, about 18 months now. We differ on the easiest, most accurate procedure.

The slots tend to stay straighter when I flip the boards over, reference faces down, and register off of the bottom of the tool, when appropriate.

But as I said, this is really a minor thing, and certainly not something about which to argue.

Patriarch

[Edwin Pawlowski]

"patriarch [e-mail]" The slots tend to stay straighter when I flip the boards over, reference

I'm going to have to go play with my tool now. I just cannot imagine using it your way with accuracy. What counts though, is the final result. Ed