I just snagged a dewalt biscuit joiner. Amazon.com: DEWALT DW682K 6.5 Amp Plate Joiner: Home Improvement this guy to be exact.

Anyhow, my house came with a workshop in the basement and many things in this workshop. The old man must have been quite the craftsman. anyway... it came with some #10 biscuits. I was making a picture frame today and used my new biscuit cutter for the first time. its REALLY smooth. Only thing is, the biscuits practically fall out. I mean really, the slot is about 1.5 times the thickness of the biscuit. seems odd.

Any time I've partaken of the biscuit greatness in the past with borrow tools, the biscuit fits snug. snug enough that with glue, it just about needs to be tapped in.

What's my deal?

 

Biscuits will swell from the moisture in the glue when assembling the project. If you want them to fit tighter from the get-go you could leave them out exposed to the air, They will absorb moisture to of the air as well and swell. I'm betting the other biscuits you have used were older and have swelled.

I have the same Biscuit cutter. Great tool!

 

The DW682K features preset depth stops for all common biscuit sizes of 0, 10, and 20. So assuming that setting is correct, there are probably 2 possibilities. 1). Operator error, moving the saw around or having it turned on, and left in the slot for too long, or tipping it up or down as you push in and let back out. Once it's positioned, the hole is drilled fast. IN-OUT... as quick as you can. You don't need to push the saw in and let it sit there for 5 seconds to clean out the slot. 2). you could have gotten a bad tool- the blade arbor could be wobbly, producing too wide of a slot, or a similar mechanical problem.

Buttering both sides of the biscuit with glue may also help. They are compressed and as the biscuit absorbs moisture from the glue it will expand and get a little tighter.

You could be right about the Dewalt producing a little wider cut than other brands. I have the same model and used to think the same thing until I got used to it.

Maybe you got one out of a bad bunch of Dewalt's Chinese blades. Another brand's blade might produce a thinner cut, so you could try a replacement blade. Also possible that the biscuits you have are a little thinner than normal.

I'd probably try cutting a faster slot, putting the glue on both sides of your biscuits... trying new biscuits... get a different blade, in that order.

 

Make sure you have the dial set to "10" so you are cutting at the right depth, and don't move the cutter while you make the cut. Keep the plate solidly on the work surface. Most all biscuit cutters use the same thickness blade, so there should be no issue there.

 

Glue is not going to swell the biscuits another 30% to make them snug. And you should not be trying to make those cuts as fast as you can. That can lead to injuries. You should be able to cut the slot slowly with no issues. My suggestion is to go and buy some new biscuits and see how they work.

 

Sorry, I'm trying to picture how you could possibly get injured by a biscuit joiner when you have one hand on the handle and one hand on the body/trigger. You don't put the wood in your lap, do you Droop? Just kidding you, man!

By saying "fast as you can" I didn't mean to infer that it was some sort of race, so I apologize if anyone got that impression. I simply meant that you just need to feed the blade in and immediately pull it back out quickly, as there is no need to hold it there. Chandler said it best when he said "to keep the plate solidly on the surface and don't move it when you make the cut".

There might also be an issue if the material being cut isn't firmly clamped. You really shouldn't hold the work with one hand and then operate the biscuit joiner with the other, one handed.

 

I use a Porter Cable, I have noticed a sloppy fit from time to time and sometimes an overly tight fit. I think it has a lot to do with relative humidity (summer/winter). The biscuits are, by no means, precision machined parts. I don't worry too much about the loose fit. Actually, it's the really tight ones that will give you a problem. You will notice the swelled bumps over the biscuits when sanding plywood. In brittle hardwood, like a picture frame, a tight biscuit could actually split the wood.

 

I have a Porter Cable 557. The blade width is 5/32". I measured several #10 biscuits and they all came in a bit over 9/64". I got them out ofmy shop which was probably 25* and 20% RH. I would measure the DeWalt blade. I think 5/32" is a standard thickness.

What brand biscuit are you using? I think Lamello biscuits are smaller than Porter Cable.

I've never had a problem with biscuits not fitting with the PC although I have sanded a few to relieve the fit and I've tossed some that were way too loose.

 

Humidity will affect the thickness of the biscuit, but not to the extent the OP is experiencing. At 30%, that is a major difference. Biscuits are designed to swell when they come in contact with glue. That is why you may see bumps in plywood where they are located. You may also notice that if you sand those bumps out within 24 hours of assembly, you will wind up with a depression in the plywood a day or two later. That is because all the glue has finally cured and the moisture has left the joint.

 

Well, thank you all! that was a ton of feedback!

I haven't measured my blade thickness, I won't lie. However, the arbor is definitely good to go. One thing I was doing wrong was cutting too slowly. I may/may not have wobbled a bit. I will give it another shot later.

I'll grab some dewalt biscuits from amazon tonight and see what they look like.

@drooplug
In terms of how loose the biscuits were fitting, we're talking loose, like you could blow on them and they'd fly out!

I'm going to grab some other biscuits, make my cuts really fast in/out, and I'll come back here to update.

Thanks for the input everyone! this community is one of the best on the net.

 

We like it too. What I enjoy is that the vast majority of the contributors don't get upset with one another... The advice given here is kind of a group effort, and everyone just wants to be helpful.

 

Alright I couldn't resist. I just measured the kerf and it's more than 6/32"!!!!! what the hell?



And here's a shot of a loose biscuit. (that just sounds funny)

 

I wonder if one tooth is slightly misaligned? The Porter Cable blade spec is .150" to .160". I don't know how that would translate to kerf width since the blade will have some runout.

In any case, I wouldn't buy a new ($50?) blade until I measured each tooth with a mic or caliper. If you end up with each tooth within specs and still get a 6/32" kerf it's probably runout or a kicked tooth.

 

The blade should be 4 mm. That would translate to .157". At 6/32", you are .187". A difference of .020 is quite a bit. 1/64" is .015" and 1/32" is .031".

Do you have a caliper you can measure the biscuit with?

 

Well, I removed the blade and measured all 6 points with a micrometer. .155 on 5 points and .156 on 1 point.

So, the blade is fine. HOWEVER, I noticed when removing the blade, it wasn't very tight. I mean it was tight but not TIGHT. so, when I reinstalled the blade, I made it TIGHT.

viola. a biscuit holding kerf. imagine that!

I appreciate all the help and feedback.