Biscuit Problem? or Not...

[JOHN THE REB]

I have noticed on several wood working shows, on TV, when biscuits are used the wood worker seems to apply pressure while inserting the biscuit. I used my biscuit cutter (RYOBI) on a recent job and all the biscuits went in rather loose. The cutter was purchased from a one time owner who used it for one project. He had it for less than 6 months. The unit was like new and cut like brand new. I didn't realize at the time I was using it that maybe the cuts were a little wide, and perhaps they are not. I purchased the biscuits from Lowes in sizes 0-10- and 20.

I am pretty sure I'm correct in assuming that as the blade would wear the slot would get smaller. So maybe the guys on TV are using biscuits cutters that need their blade replaced. I finished my project but had to take time to make sure everything was aligned before clamping.

Question is: should the biscuit be forced in slightly or should they just ease in.

On my project the biscuit would actually lean left or right a little more than 1/16" with the glue in the slot. It would be impossible to hold a board vertical without the biscuits falling out.

I'm confident I used the cutter correctley, but I'll accept any advice and information on the biscuit question.

PS. I called the guy who I purshased the cutter from and he told me the cutter was in the exact condition that he purchased. I asked him had the cutter blade been sharpened or replaced and the answer was no. He even offered to refund my money if I was dissatisfied. (there were no hard feelings)

Thanks for any advice!!!

John:dontknow:

 

[nelsone]

There is often some variation in the biscuits themselves. Once glue is applied the biscuits will start to swell and fill the void. They shouldn't be too loose though.

 

[Canuck]

I use a Dewalt and have found that there can be some small variation in the thickness of biscuits out there. Usually I need to press (not hammer!) the biscuit into the slot cut, though.

If you have a set of dial calipers, you may want measure the thickness of the blade and compare that to the biscuits that you have. (If you "tip" the face of your biscuit cutter a wee bit while cutting the slot - that too will affect your fit.:dontknow

Wayne

 

[Rob]

Depends on the wood also, you want to be able to adjust them. I've never had a problem and mine just drop in.

 

[Bas]

I had some issues with loose fitting biscuits at first because I didn't keep the cutter perfectly steady while plunging in. But, if you're confident you're using the machine correctly, it is possible the blade is oversized. 1/16" is way too much slop for biscuits, even with the variation in biscuit thickness/ humidity, especially when you factor in the swelling from the glue. Do you have some digital calipers? I'd check the size of the teeth and compare it to the thickness of the biscuit. If the blade is good, the machine could have excessive runout, but you'd probably see other problems then as well (burning/ noise). I assume you bought some different biscuits - it could just be this was a bad batch. It's certainly cheaper than buying a new blade.

The blade doesn't really get thinner from usage BTW, just dull.

 

[Ray Martin]

I use a Porter-Cable joiner and P-C biscuits. They are slightly snug when I push them into the slots. A biscuit should move side to side in the slot but not up and down. Biscuits are generally compressed beech and will swell as they exposed to the moisture of the glue.

There could be slight differences in brands of biscuits but a 1/16" seems like a lot of play. I agree with Bas... take the less expensive route and try another batch / brand of biscuits.

 

[Skymaster]

Biscuits do vary no matter which brand you buy;
Once you open the bag put them into a double ziplock baggie, then store that in a plastic storage container like Rubbermaid etc food storage critters.
What I did is to take a block of wood, like a sanding block size, chisel out the center to the shape of the biscuit enuf to hold it. If I get the thick ones I just put em aside and keep goin. when I get a pile of em I put a pc of 80 or 100 grit on a table and just run em on the sandpaper till they fit, toss em into the bag and u r good to go

 

[toolferone]

The cutter should be 5/32" wide. Cut a slot and measure it. If the slot is too wide but the cutter teeth are right then you might have some play in the blade arbor. The biscuits will expand with mositure, so yes as mentioned lkeep them dry.

 

[McRabbet]

You would have more problems if the slot was too tight rather than too loose. The biscuits are designed to swell a little from the wet glue and if the slot is too tight, there is a chance the expanded biscuit may push the wood being joined enough to be reflected as a "proud" spot on the surface. Biscuits should fit all the way into the slot while dry and may require a small tap of a hammer when glue is applied. It is imperative that you keep the biscuits dry -- if you have a small packet of Silica Gel that comes with some products, drop it into the air-tight container you use for the biscuits (P-C provides a screw cap container with their biscuits).

 

[fergy]

Another trick with the biscuits, if they are fitting too tight, is to toss them in the oven in a baking dish at 350 for about 30 minutes or so. Drives the moisture out, and they shrink. No hammering required.

 

[Bas]

Another trick with the biscuits, if they are fitting too tight, is to toss them in the oven in a baking dish at 350 for about 30 minutes or so. Drives the moisture out, and they shrink. No hammering required.

Yup. And if you're lucky, LOML will ask you "whatcha baking?"

 

[fergy]

Yup. And if you're lucky, LOML will ask you "whatcha baking?"

She likes this better than when I dry baking soda to create washing soda, or recharge dessicant, or sterilize aquarium sand.

 

[CaptnA]

sounds too obvious but are you using the right size biscuit?
and you might measure the blade itself. If he only used it once and sold it, that could be part of the reason why. not to imply anything, just a thought.

 

[Travis Porter]

Along with all the other suggestions, do an exeperiment. Get a couple of scrap boards, put biscuits in them, glue and clamp them up as normal, and then once it is dry, rip the board down the middle and see what you have.

I you have space top to bottom and they aren't firm, you know you have a problem. If you have a lot of space end to end/lengthwise, your cuts are too deep.

Let us know what you find/do.

 

[Charles Lent]

I've been using biscuits since they first became available. I always store my biscuits in sealed plastic containers as soon as I open the bag that they come in and I have found that there is still a significant variation in their thickness when I try to use them. There is no brand of biscuits that I've found that has a precise thickness. they vary significantly no matter who makes them.

If I'm trying to get a very close board surface alignment I sort through the biscuits that I have to find the ones that fit snugly. The ones that are snug will work well as long as they aren't so snug that you can't easily press them in with two fingers. In the summer I leave the ones that fit too loose on the workbench for a few hous or more to pick up moisture from the air. When they swell enough to fit snugly in a biscuit slot I then use them. If they won't be used for a while I then store them in a separate container for later use. I never mix them back into the original container with the dry ones. I have sometimes found myself short on supply and in need of thicker biscuits with only some thin ones left. I've found that a single eyedropper drop of water on the center of each thin biscuit and a couple of minutes wait will thicken them significantly enough to use, but sometime it will make them too thick. If the humidity is low, these "too thick" ones may become usable again if left on the bench.

When I first started using biscuits I always made sure that both sides of each biscuit and their slots were coated completely with glue before assembly and I paid no attention to how thick or thin they were as long as they fit in the slots. I later found that this method of glue up was causing the biscuits to swell excessively, leaving a very slight bump on the surface of the boards at the biscuit locations if the biscuits were located less than 3/4" below the board surface. This is especially true in soft woods like pine. If these boards are surface sanded within a few days of being joined together these swollen areas will be sanded off. Then, when the moisture in the board equalizes over the next month or so you will discover that the table top that you biscuit joined together now has small biscuit shaped dents in it's surface. This is due to all of the moisture in the glue and the biscuit drying out, causing the biscuits to shrink and pulling a depression in the surface of the wood. I now glue only the edges of the boards and leave the biscuits relatively dry, using them only for edge alignment when gluing up panels that are to be used for tables, cabinet surfaces, etc, or wherever such a depression might be seen in the final product. The boards that I've joined this way have never separated and these dents have never again been a problem.

Todays glues are stronger than the wood and when used properly they don't fail. In most cases, biscuits aren't necessary for joint strength when used in flat panel assembly, but they do simplify edge alignment in the glue up process. In other types of assembly, fully glued biscuits can significantly increase joint strength and they are fast and easy to use.

Charley

 

[JOHN THE REB]

Re: Biscuit Problem? or Not...FOLLOW UP...

Thanks for all the input concerning my bisquit problem. I took the cutter/blade off and had a friend that works in quality control, where I retired from, and he did some measuring for me. Using a Coordinate Measuring Machine he found that the blade was not consistant in dimension at eight points at the base where the teeth start. The blade was horizontal when measured. In otherwords it wobbled like a out of round brake rotor. Also the carbide teeth were at differnt heights when held vertical from the flat he was measuring from. He advised me to can that blade and get a new one.

Yup, got it cheap, fellow only used it once, as the old proverb says:

CAVEAT EMPTER
Thanks guys,
john :realmad:

 

[sapwood]

Re: Biscuit Problem? or Not...FOLLOW UP...

. . .
Yup, got it cheap, fellow only used it once, as the old proverb says:

CAVEAT EMPTER
Thanks guys,
john :realmad:

Ouch!
Maybe he thought it was a retractable angle grinder :wconfused:

Roger

 

[lottathought]

This has been an interesting thread.
And it makes me want to ask a few questions.

I had no idea that biscuits needed to be this precise.
So I take it the Harbor Freight biscuits are not the deal that I thought they were?
If not..what do you consider to be the best value/quality balance of biscuits?

 

[RandyJ]

So I take it the Harbor Freight biscuits are not the deal that I thought they were?
If not..what do you consider to be the best value/quality balance of biscuits?

If they fit, use 'em!! As mentioned NONE are perfect...

 

[Cato]

I normally use the Porter Cable biscuits, as they seem to fit nicely with the slot that my PC biscuit cutter makes. The fit for mine is usually just shy of snug, which suits me because you do want the biscuit to expand when the glue is applied.