Biscuit Cutter issues???

[Jay Yoder]

This may be a silly question but i was wondering how "tight" and how deep the biscuit is supposed to fit in its slot. I cut some biscuits tonight and noticed that there seems to be some play perpendicular to its length. Also the depth of cut seems to be off. In a finished slot, how much of the biscuit should be sticking out? A bit shy of 1/2 the biscuit? It seems that they fit very loose. maybe that is by design so there is room for the biscuit to swell. is there any standard depth to confirm that the cutter is set up ok? In other words, for a #20 how deep should the slot be? I have not had alot of experience with using biscuits as you can probably tell.

[Peter Quinn]

Biscuits should be snug in the slots, not much play perpendicular to the slots length. You shouldn't need a hammer and pliers to put them in and out in a dry fit, and they should not fall out of the slot when the board is inverted. Friction fit I'd call it. I have never even considered the depth, never had a problem there.

The length of the slots is greater than the length of the biscuits to allow for lateral adjustment, but the kerf of the cutter is very close to the thickness of the biscuits to create good alignment between to boards being joined should that be necessary. If the slots are sloppy you may have a wobbly blade or a bad batch of biscuits.

[Jay Yoder]

I figured it was friction fit, but i am concerned that maybe my cutter is "over" cutting. how deep should the slot actually be? It could be the blade or the actualy machine. It did not look used at all actually, so i would figure that eliminates the blade. It is a craftsman and i have had issues with some of their stuff lately.

[Gene Michael]

Ditto what Peter says. Also, check to make sure the biscuits are the correct size for the cutter. The biscuits will swell to make a very tight fit when they are exposed to the glue, but if they are loose to begin with, the pieces that you are joining will be out of alignment. I've been using Bosch biscuits from one of the borgs and have never had a problem with them.

[Wayne Cannon]

Biscuits will range from a gravity drop-in (but not wobbly sloppy) to a snug/gentle manual press fit in a dry joint. If you don't keep biscuits dry in a sealed container, they will absorb moisture and often expand enough that you can't press them in by hand. Once you add glue, both biscuit and slot will expand similarly to make a pretty tight fit unless you work quickly (I've had to rely on clamps to pull them together at times).

[Walt Caza]

Hi Jay,
As far as biscuit depth, I cut a sample slot, then insert a biscuit.
Pencil a line onto the biscuit itself, by following the edge of the board.
I also mark a hash mark touching around the center of that line, and
pulling it away maybe 1/4". (so it is easily visible)
Then spin the biscuit 180 degees and mark the depth line again, and I
like another hash mark near the middle.

Pull out the biscuit and now the overlap is visible. It is equal to the total
'play' of both slots in the closed joint.

The hash marks indicate from which direction each particular line was drawn.
If your slots are not deep enough for the joint to close, they will
crisscross. I shoot for maybe a 1/16" gap between my indicator lines.
This provides about 1/32" of extra depth per joint side.

You only need to check this way each time you change your joiner's
biscuit size setting. Like many workshop concepts...
this one is way quicker and easier to do, than to try to type, while
away from the shop, at 3:00am.

I just started doing this when I was new to biscuit joinery.
I am certain many ww'ers have a similar system.
I believe that we tend to develop similar shortcuts, tricks and techniques.
I would not have thought to share this one, had the issue not come up.

I hope it helps you set your biscuit slot cutting depth!
be well,
Walt

ps a little biscuit play in the thickness of the slot has been no big deal for me.
A dry biscuit does not make what I would call a snug fit...
and yes, the swelling will snug them.

[Barry Vabeach]

Jay, there is usually an adjustment ( apart from the biscuit size setting ) that allows you to adjust the depth of cut to be deepor or more shallow ( usually a nut on a threaded rod) This adjustment would apply to all biscuit sizes - so if you adjust it to cut 1/64 deeper for a 20 then it is now, it will cut 1/64 deeper for a 10 and 0 also. Since the vast majority of the holding force is the compression from above and below the biscuit, I don't normally worry how much the biscuit moves laterally. the reason I did adjust mine to be a little deeper than set at the factory was that if my slots were off by a quarter inch or more or I had a little spring in the joint, the biscuit may keep the joint from closing. If you decide to adjust this, make up a 2 samples, making sure you cut the slot right on the mark, then insert the biscuit, hold the two samples together and move them side by side to see how much distance there is between the 2 marks before the biscuit interferes with the joint closing. Once you adjust the depth, make up another set of samples and do the same measurements and set it where you are comfortable.

[john bateman]

If you want to get anal about it, Rockler has a gauge for this.
http://www.rockler.com/product.cfm?page=18003&filter=biscuit

http://images.rockler.com/rockler/images/31447-01-200.jpg

[Gary McKown]

One of the things about biscuit cutters that I noticed early on was the tendency of the cutter to rock slightly in use (especially for a top-handle machine). The force applied on entry tends to tilt the machine upward, and this force is relaxed on withdrawal. This means a slightly different angle of entry and exit, so a slightly enlarged slot. That fairly short fence and thin face, plus any slop in the slider, contribute to this situation. Wherever possible, I use the shoe of the machine as the reference plane.

One other thing (of which I am sure you are aware) - the cutter should be going at full speed before taking the plunge.

[Jay Yoder]

Thank you for your responses! I checked it tonight and ended up using the fine adjustment so that when i cut the biscuit joints there is less than 1/8" "overlap". that seems to really have helped the situation. I wish i had that gauge from rockler! that is a neat toy!! I am not real thrilled with the "precision" of this biscuit cutter but not sure i would use it enough to justify picking up a PC version unless i found a solid used one...

[Barry Vabeach]

Jay, while 1/8 might work for you, I am kinda sloppy when I do the marking and the cutting, so that wouldn't allow enough tolerance for me. I need at least 1/4 movement to allow for how roughly I mark and cut.

[Roger Everett]

I use the same method as Mark mentioned. Pencil line, 180*, pencil line, 1/16" between lines. The slot cut is slightly longer than the bisquit because the blade is a slightly larger dia. than the bisquit. Makes the exact placement of bisquit less critical, and gives a little slide as pcs. are put together.
Roger

[Walt Caza]

Hey Roger,
Who's Mark?
You gave me a good chuckle!
Have a great day...
signed,
Mark (but usually known as Walt)

ps good times!

[Roger Everett]

Sorry about " Walt ", I'm not going to claim a senior moment, I've had CRS all my life.
Note: full credit and agreement to Walt on my post.

Roger -- I think--Yea, I just checked mine or Roger's drivers licence.

[Jim Heffner]

I read your post about the biscuit cutter....and wondered about something? Did you have your biscuit cutter ( size adjustment)set to the proper size for the biscuits that you needed to use? Also, were your biscuits stored in an airtight container? If they weren't...moisture and humidity may have caused them to start swelling a bit and that would keep them from fitting in the slots as they were intended.Something to think about and check anyway.

[Dale Lesak]

The instructions that came with my cutter was."Stop the tool at the bottom of the cut and then remove it" That way your not cutting both going in and coming out. this was with a PC machine. It dose help.