Are biscuits good for aligning edge glue ups, or are dominos better?

[dirk martin]

I thought using a biscuit joiner and biscuits were good for helping align 4/4 lumber, when performing edge glue ups. I've seen some say they are perfect for that. I've read others say the biscuits are sloppy, and thus are poor for aligning your boards.

Are Festool's domino's a better approach?

[Peter Keen]

I found biscuits sloppy, so they didn't line up exactly. Mind you, I have an inexpensive biscuit jointer - I hear that the name brand models are better. I ended up just edge joining without biscuits - that has worked well for me for years.

[Steve Excell]

I have a relatively-cheap DeWalt bisquit joiner. I find that with the proper set-up of the tool for centering, the bisquits actually help align my edge glue-ups...which I do with pipe clamps and cauls. I start by adjustng my joiner fence for dead-on accuracy...using scrap pieces of wood. When doing edge glue-ups, I flip the boards and use my bisquit joiner twice...thus assuring absolute centering. I fill the bisquit slots with plenty of glue.

I live in a very humid locale...the Pacific NW in Washington State. I keep my bisquits tightly sealed in plastic jars with dessicant sacks. Some woodworkers run into problems by buying cheap bisquits or leaving them exposed to the environment of the shop.

[Mike Henderson]

There's no reason to use biscuits, or dominoes for that matter, when doing a panel glue up. You can achieve perfect alignment with cauls. Biscuits don't do a whole lot - they certainly don't add any strength - and they have certain drawbacks. One drawback which happened to a friend of mine was that he wasn't careful about the placement of the biscuits and when he cut the panel to size, the biscuit was exposed. Another problem which can occur is dimples if you sand too quickly.

In my opinion, they are more trouble than they're worth. Use cauls.

Mike

[Dominic Carpenter]

I agree with Mike. I used to use biscuits to align large edge glue ups, but I use cauls now. It is faster, no additional machining, and as Mike said, no worries about trimming and exposing biscuits. Get some packing tape and use your scrapes laying around the shop and you are in business.

[Keith Hankins]

Well I can answer as I've used both. And the answer is Neither! Let me explain my answer. I've used both, the biscuit from my days of learning from Norm. I had the PC 557, and it did do ok but the fit is not perfect and you will have a little bit of slop so it won't be perfect. The domino is cool and I used it a lot. I was a big fan for M&T.

For alignment, you just don't need it. You can get just as good once you realize with modern adhesives, and also realize you don't need to apply 3 tons of pressure across the joint to get it to hold, you will be just fine. I can't imagine wasting the time for that now. Clamps place properly and the right pressure applied, will take care of it.

If I had to have one, though the Domino hands down, but it's expensive! I sold my Domino to buy my Big Powermatic 719T M&T machine.

[Lee Schierer]

If you want perfect alignment use a glue joint router bit or shaper cutter.286163 set up takes a bit of effort, but if you get it right the boards will be perfectly aligned and you will also get a really strong joint.

[Prashun Patel]

Even Dominos are less than perfect. Cauls are superior in many ways. They're faster (once properly made). I highly suggest you spend the time to make a couple.

[John TenEyck]

IMHO Lee's answer is the only one that will give you "perfect" alignment. But for normal panel glue-ups, ones you are going to plane or drum sand flat later anyway, there's no reason to do that either. The key to getting a panel to glue up without cupping is to joint the edges so that the assembled panel will stack up perfectly plumb, like this:

286166

When you do that you don't need cauls during clamp up. Clamps top and bottom will keep the panel flat.

286167

Edge alignment requires nothing more than finger pressure as you tighten the clamps, or at most a whack or two with a mallet. You should easily be able to maintain less than 1/32" difference, almost perfect if your boards were milled properly.

286168

It's about working cleanly. As I see it, the rest is just band-aides.

John

[Prashun Patel]

"It's about working cleanly. As I see it, the rest is just band-aides. "

John's a better man than I. Despite my best efforts, I often end up with a board or two that are ever so slightly cupped or bowed (enough that they won't lie coplanar to the adjacent board, but can still be gently coaxed into position.) Bar and pipe clamps can be clamped along their length to the joint to serve as a caul, but 'real' cauls can be made cambered, which gives them more even pressure along the entire joint, leaves no iron stains, and will not gum up the clamp's bar with glue.

[Sam Murdoch]

Well I'm going to jump in with a dissenting view from most of the comments above - I use Dominos these days but for many years have used biscuits for aligning the face surfaces of glue ups and I think they are GREAT!. Dominos are better as they are more precise but biscuits nearly just as good. Actually the Dominos fit too tightly in the horizontal orientation so I only cut one at the domino width and use the elongated holes for the remaining. Biscuits are sloppy enough end to end so that is not an issue. Set them just below center line for 3/4" thick stock and at least 3/8" in other thicker dimensions and you will not have issue with a dimple telegraphing to the surface (unless you then plane or sand 1/2 of your surface away). I have never had this happen in 100s and 100s of glue ups. I agree that biscuits in particular add no structure to the joint but they do certainly help for alignment.

You do need to think about the placement from the outside edges because it is very possible to disregard that aspect and later cut your finished end of a table top right through a biscuit - that really is a frustration - so pay attention. I typically start my domino layout from the established "finished" center and know to keep at least 3" away from the anticipated ends. Cauls may still be in order to help keep the glue up flat but at least you are working efficiently and confident that your top surfaces are aligned.

I typically face plane and edge joint my boards so that I can stack them as John TenEych describes. I most often glue them up in a vertical stack with my Bessey K clamps and often can then take the glued up assembly off the bench and set it aside to make room on the bench for the next glue up. I consider myself a pretty clean woodworker but in the midst of many glue ups there are moments when - "Edge alignment requires nothing more than finger pressure as you tighten the clamps, or at most a whack or two with a mallet." is a lot easier to write than to achieve in the real world. Biscuit or Dominos (spaced 6" to 10" apart depending on the inclination of the boards and the overall length of the assembly) make the glue up a stress free activity in my shop.

Another advantage is when you are using boards that are not equal thickness or simply irregular due to knots or other defects, along the bottom surface - you can still align the tops and disregard the underside.

[Wade Lippman]

Dominos are better than biscuits, but biscuits are adequate. I have never used cauls, but frankly I don't often use anything.
If you wood is properly jointed the board should go together without too much drama. I clamp loosely, force one end even and tighten that end. Then force the other end even and tighten that end. Occasionly the middle will be off, but you can almost always even the up with a rubber mallet.

I sold my biscuit joiner because I never used it. If the wood is just not flat, I will use biscuits to force it even; but that is most unusual.

[Kevin Jenness]

I do as John Ten Eyck does. I will use cauls if the material is thin enough to buckle under clamping pressure, otherwise no need, just clamps balanced on either side of the panel. Biscuits are a quick way to ensure alignment within 1/32", and I expect to be closer than that with a little manipulation. Dominoes are a bit more precise, but slower to machine. Dowels are also very precise, but require very accurate drilling.

[howard s hanger]

I do a number of cutting boards every year and bought a Panelmax from Peachtree last year to do the glue ups. It takes a few minutes to get it set up so I do a dry run first. Once it's all set, just glue the edges and stack, drop the top screw clamps in the slot, tighten a bit and it's all done. Alignment is spot on and it doesn't take up any shop space.

[Jim Andrew]

I watched the video Saturday that Rod Sheridan posted the link to, the Felder video on the CF741, they use the shaper at 45 degrees to run the glue joint on miters, so you get perfect alighment on mitered corners. Pretty awesome.

[glenn bradley]

Splines and glue-joint router bits are only as accurate as the profile is to the surfaces to be aligned. That is, running a sort-of flat panel across your flat router table will give you a sort-of true glue-joint profile to mate to. Hand routing this profile will do better as the smaller router base can follow the contours of a not-so-flat panel. The resulting profiles can be use to try to force the parts to align. I agree with Mike, Dom, John and others; mill your boards flat and align with cauls or by touch. I have used splines or profiles to increase strength when edge gluing thin stock but, the purpose there is not alignment, it is increased glue surface.

[Rod Sheridan]

There's no reason to use biscuits, or dominoes for that matter, when doing a panel glue up. You can achieve perfect alignment with cauls. Biscuits don't do a whole lot - they certainly don't add any strength - and they have certain drawbacks. One drawback which happened to a friend of mine was that he wasn't careful about the placement of the biscuits and when he cut the panel to size, the biscuit was exposed. Another problem which can occur is dimples if you sand too quickly.

In my opinion, they are more trouble than they're worth. Use cauls.

Mike

Exactly, they're not needed at all for edge glue ups.............Regards, Rod.

[Chris Fournier]

This topic comes up several times a year, sadly I can't help but respond in support of the the now despised biscuit joiner.

If your biscuit joiner is making sloppy joints it has more to do with the operator not paying attention to the biscuit thickness than the machine. Get the MC of the biscuit right and there is no slop, simple as that. Also I have looked at some guys "crappy" biscuit joiners and with nothing more than a 6" rule I've been able to show them that their joiner is maladjusted. Tune your tool!

To say that biscuits add nothing or are never needed when edge gluing isn't true, if I told you that they were always needed when edge gluing it would be equally unhelpful.

If you have a simple glue up where you have done a dry run and you know that you can manage chaos to the last clamp then you can likely go without any biscuits, cauls or what have you. If however you are at your limit (helper or no) and there are larger surfaces to glue, lots of them, or you are racing against open time then by all means use biscuits to help you get the glue up done quickly and accurately. Think of a thicker bench top for example. In this scenario there is so much glue surface area that it can be hard to shift boards once the glue surfaces have been joined.

I rarely use cauls when edge gluing and biscuits are used on a case by case basis as expalined above. T-bars to elevate my work off of a very flat assembly table, clamps at the tables end and away I go, after a dry run that is.

The biscuit joiner is like any other tool in your shop, it is only as good as you are. In my shop it is simply one of the best value tools that I have ever owned - think of cost per biscuit and you can't help but be impressed. The Domino is many fold more expensive per operation and it simply isn't needed for face alignment work if you have the more economical biscuit joiner.