Biscuits...

[Guest]

Hey Biscuit Masters,
I'm old school... dado, spline, rabet, lap joints and occasionally a dowel kinda guy.
In an effort to speed up my build, I bought a #557 PC bisuit cutter... OK, Plate Joiner.
Question... Do any of you guys presoak your biscuits?
I'm using the factory set determined depth for a #2.0 biscuit and it sure produces a pretty sloppy joint with the buscuit dry. Even presoaking the biscuit for a few minutes still gives me a loose joint.
I was going to epoxy my radiused/eliptical framing members together, but I'm considering using plastic resin glue now, so that water will be pressent in the glue.
Anybody got a trick to get these biscuits to "rise" just a tad more?
What I'm seeing is... I could decrease the depth of the factory set depth just a bit, using the fine adjustment screw and that would take some of the slop out, but the thickness of the cut really seams pretty loose even with the biscuit swelled up.
I don't know... Maybe I've always made my spline joints tighter than they should've been???

[madjack]

Dean, it is supposed to be a "sloppy" fit...the water in the glue swells them up...they are made of ground walnut shell and expand a good bit...which is why I telling you my doubts about the epoxy
madjack

[asianflava]

Dean, if you are trying to speed up the build, I'd suggest using pocket holes and screws.

1 You only have to drill 1 piece, instead of cutting 2 biscuit holes

2 The piece is held in a jig so there is less chance of messing it up

3 The screws will clamp the pieces together so you don't have to wait for glue to setup

4 When you fo use glue on a joint, you don't have to clamp it together.

[mikeschn]

Dean,

If your biscuits are that loose, then you are letting your jointer move when you cut your slots.

It can't move, and you can only make one pass at the slot.

My biscuits are a light press fit into the slot, and sometimes, I even need a hammer to tap them in...

Mike...

P.S. You're practicing on scrap, right?

[bobinohio]

Dean,

My results have ben simillar to Mike's. If they need to be tapped with a hammer- a minute in the microwave usually solves the problem. The "normal" biscuits I've used were compressed beech wood.

I also like pocket screws better than biscuits- they wind up being quicker.

In addition to Mike's suggestions make very sure that the fence (or whatever lines things up) is square to the blade. The very first ones Porter Cable made were a major pain in this regard. There is also a slight possibility that your blade may be oversize. I heard of a tablesaw blade coming through the chain with a carbide tooth that wasn't side ground.

You might want to check out Woodhaven. They used to have a very large selection of biscuits and related equptment- routers too. Theirs is another site I can't search but they used to send me catalogs that had fairly detailed instructions

http://www.woodhaven.com

Bob

[Guest]

Bob,
I'll check the teeth with a set of calipers.
Thanks.

Mike,
The machine isn't being allowed to move around while making the cut.
I'm only making a single plunge in each cut and as Gage would say, "a course" I'm using scraps to test it out.
I'm even using PC biscuits.
BTW- I can get a snug fit with the biscuit if I soak it for about five minutes in very hot water, but not so snug that I'd have to tap them in with a hammer...

[madjack]

Dean, I have never had to tap them in...usually there is just the very slightest bit of "wiggle" room...usually more so side to side than up and down...I certainly wouldn't recommend soaking in water
Madjack

[Guest]

The salesperson I bought this from tells me that my machine was designed to make a loose fit with a dry biscuit... So as when the biscuit swells, it doesn't shove the glue out of the way. He did mention that the biscuits can vary in thickness from batch to batch.
Oh... I didn't find any over sized teeth in the blade.

[Chris C]

Somethings definately amuck here! Biscuits should just barely touch the sides of the slot when all is dry. They swell when glue is applied. But they shouldn't be as loose as you are describing.

[Steve Frederick]

With my setup, a Dewalt machine and Porter-Cable biscuits, I get a tap-snug thickness and a slightly long slot. I've been using titebond glue. The joints are plenty strong. Dumb question...Are the biscuits the same size as the depth setting on the machine?

[Chris C]

Steve,

There are 4 different bisquit sizes...........and, I think, all machines can be adjusted for each.

[Chris C]

The salesperson I bought this from tells me that my machine was designed to make a loose fit with a dry biscuit... So as when the biscuit swells, it doesn't shove the glue out of the way. He did mention that the biscuits can vary in thickness from batch to batch.
Oh... I didn't find any over sized teeth in the blade.

Dean, I forgot to ask you if the runout was true? The teeth can be the proper width, but if the blade is wobbling (even microscopically) the slot will be wider than intended.

[Steve Frederick]

Steve,

There are 4 different bisquit sizes...........and, I think, all machines can be adjusted for each.

My point!

[Guest]

Chris,
It may be that I've prescribed myself to somebody elses' tollerances and it seems sloppy to me.
I've certainly had to use a hammer to insert dowels, but they had swirled glue recesses in them as to not starve the joint of glue and as far as spline joints go... I was taught to make a snug, but not tight fit, to where you could completely bring the joint together by hand once glue was applied. (That's how I was taught, but more times than not... I need clamps to snug up the joint)
Maybe these biscuits just use a bit more clearance than I'm use to.

This will explain how loose my joints are...
Inserting a dry biscuit into a dry slot and holding the test piece upside down, one out of five biscuits fell out. The other four required a slight tap on the table with the test piece to get the biscuit to fall out.
I'm going to do some test glue ups and see how well the joints hold with plastic resin glue.

[Chris C]

Dean,

If you have to "drive" a dowel into it's hole, you HAVE starved the joint. All you've left to hold is the spiral of glue going down the dowel........and woodworking glue will NOT fill a gap wider than .005" and hold solidly. The bisquits are the proper thickness if you can slip a piece of typing paper between one side and the side of the slot..............just as with a mortis and tenon joint. (So it sounds to me as if they are a proper fit.)Bisquits are compressed Beech or Birch and will soak up the moisture in the glue very quickly and expand to fill the slot. A good example is to coat one in glue and install it to one of your boards. Wait 3/5 minutes and try to stick the exposed portion of the wet bisquit into the corresponding slot in the other part.....................it probably won't fit. There is an on-going arguement among the woodworking community as to whether or not bisquits are a "suitable" joint, as compared to a mortise and tenon. I am among a group who consider the bisquit based on it's strength, versatility, and ease of execution................of course, keeping in mind the end use of the item being crafted. In other words, I think bisquits certainly have their place in all types of assembly.