When and when not to use biscuit on tabletop glu ups?

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Forum topic by RonGoldberg posted 07-02-2013 01:28 AM 35996 views 1 time favorited 22 replies Add to Favorites Watch
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46 posts in 3408 days

07-02-2013 01:28 AM

Topic tags/keywords: question

Perhaps I am brainwashed by our old pal Norm (The New Yankee Workshop)......but what is the deal with using biscuits for aligning and gluing up a couple of boards to assemble a table top. Some people swear by them and others don’t use them at all. Does anyone have a good rule of thumb here?

Ron G
(McLean, VA)

22 replies so far

View jusfine's profile


2422 posts in 3976 days

#1 posted 07-02-2013 01:41 AM

Ron, I used the biscuits for alignment as you mention for many years, not so much for anything else as I believe the glues are much better than they were years ago.

Biscuits worked well, but I have since purchased a Festool Domino and it works much better for alignment (no slop).

I have completed a number of glue-ups without dominos or biscuits when the material is thinner, but I prefer to use them “jus’ because”.

Maybe Norm got to me as well…

All the Best!

-- Randy "You are judged as much by the questions you ask as the answers you give..."

View RodNGun's profile


118 posts in 3354 days

#2 posted 07-02-2013 01:45 AM

Use your biscuit joiner until you get your Domino… :)

My Domino has improved the quality (and reduced the sanding) of my glue-ups by leaps and bounds.

View CharlieM1958's profile


16292 posts in 5269 days

#3 posted 07-02-2013 01:59 AM

I used to use biscuits for table top glue-ups. Through reading other opinions, and through the process of trial and error, I eventually decided they were just an unnecessary extra step.

The problem is that you can actually cause a misalignment if you’re not really careful cutting your slots. Also, swelling/shrinkage at the site of the biscuit can be a problem.

-- Charlie M. "Woodworking - patience = firewood"

View Loren's profile


11135 posts in 4698 days

#4 posted 07-02-2013 03:26 AM

They can be used (as can dowels and loose tenons) to
shift variances in board thickness to the back of the glue-up –
but more importantly they can be used to coax boards to
follow their neighbors.

In milling long boards, you will find it not pragmatic to
get them totally flat on one side. You’ll waste a
lot of wood if you insist and have to buy thicker
lumber. Instead, they can be coaxed into relatively
flat glue-ups under tension.

I use a Plano press for this, but biscuits work too.

What Charlie says applies and biscuit cutters vary
in quality. I have never used a Lamello but they are
the best and maybe they cut more consistent

If you are laying out boards on sawhorses with glue
on the edge and closing the joints with bar clamps,
biscuits could definitely make the job more manageable
as the glue will start to set before you’re ready for
it to do so otherwise. With the biscuits you can do
a dry run and you’ll get the same alignment when you
do it with glue.

View Lee Barker's profile

Lee Barker

2172 posts in 3901 days

#5 posted 07-02-2013 03:02 PM

I concur with Charlie: Unnecessary step.

Loren: The Lamello is a fantastic machine. I’ve had my Top 20 for 14 years (I looked it up!) and it still performs flawlessly.

If you’re unsure of your ability to walk a number of boards for a glueup, or if it is excessively long, glue up in pairs and then glue two pairs together, etc. You’ll learn how to use the clamps to exert force exactly where you want it, and you’ll learn to finesse the properties of the glue.

There are lots of interesting and practical uses for biscuits. Edge to edge glueups is not on my list.

Norm is another whole subject. Let’s leave it at this: He is very skilled at everything he does.



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

View Grandpa's profile


3264 posts in 3726 days

#6 posted 07-02-2013 03:38 PM

How did we ever get by before biscuit cutters were invented? Just fine and we only had white glue. Tough world out there and so many things to spend your money on.

View Nicky's profile


711 posts in 5142 days

#7 posted 07-03-2013 03:08 AM

A lot of good points made in this thread.

I use a Freud biscuit cutter, and I do need to pay special attention when cutting to get an accurate slots. I use biscuits for alignment and for the last few years, no glue on the biscuits or in the slots.

I’ve read that the biscuits may react differently to moisture then the stock being glued and may telegraph through. I don’t have any first-hand experience with this effect, but sounds reasonable.

Modern yellow glue is amazing stuff. I’m not using the biscuits to add strength.

Biscuits are welcomed in my my shop.

-- Nicky

View pintodeluxe's profile


6344 posts in 3864 days

#8 posted 07-03-2013 03:58 AM

Don’t underestimate the strength of biscuits. If there is any doubt, do my little experiment at your next family gathering. Edge join two boards with biscuits… but no glue. Soak the boards in water for a few minutes to swell the biscuits. Now pass the board around to see if anyone can separate the boards. None of us could, even standing on one side, with mighty pulls on the other.

I think biscuits got a bad rap because of one FWW article that tested a single corner biscuit joint into end grain. You will never encounter a single biscuit joint at a corner in practical building applications. I use them at all four corners for web frames in my dressers and nightstands. You can stand on one side, and pull with all your might, and you cannot separate the joint. In contrast, plain end grain glueups are pretty easy to separate. In the article, a single biscuit joint was not much stronger than a simple butt joint. However, with long grain edge joints, you will use many biscuits and I assure you the joint is very strong. I use a Dewalt joiner, and have found that the Dewalt brand biscuits fit the slot more snugly than other brands (like Porter Cable). This helps with a good strong joint.

That said, I have never had a long-grain glueup fail—- even without biscuits. If I have some extra board thickness to work with, I will use biscuits. Then I run the plank through the planer to flatten it out. If I am joining 3/4” boards, and I want to keep the panel as thick as possible, I will actually skip the biscuits. They can cause a slight misalignment if there is sawdust under your workpiece, or perhaps under your jointer. Using a shop vac on the joiner, rather than a dust bag helps a great deal.

Never use biscuits on 1/2” or thinner panels, because the position of the biscuit will be telegraphed to the surface. This isn’t a problem for 3/4” or thicker panels, so long as the biscuit slot is centered on the thickness of the workpiece.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View NoLongerHere's profile


893 posts in 3726 days

#9 posted 07-03-2013 12:05 PM

I thought I was the only one having this problem. Now, I only use them to attach face frames to casework.

I went through the same frustration (THANKS NORM!) when I first got my BJ ….. wait, that sounds weird – biscuit joiner.
I couldn’t understand how the joints could get that much out of alignment. Wasn’t that the point of installing them? So, I stopped using them on glue ups (Tightbond) years ago. Never had a joint fail.

Always made me cringe watching Norm clumsily glue something up. What mess! Still a big fan. I wish he would make more episodes.

View fredj's profile


187 posts in 2868 days

#10 posted 07-03-2013 12:16 PM

I use biscuit at times but not for edge to edge. You just don’t need them. If have been having a hard time getting boards to line up, try clamping up them dry to see what you will need to do. Then go back and glue’m up.

-- Fredj

View realcowtown_eric's profile


638 posts in 2987 days

#11 posted 07-04-2013 05:52 AM

Buiscuits can have their place no doubt, but for a good lamination, the rubbed joint has served for centuries, and no doubt will continue to do so.

But the biscuits do hold the work from sliding around as the clamps are applied.

In fact, get a little too keen on quick turn around time, and you might find that the slight moisture variation where biscuits are used will telegraph through to the finished surface. , same as a glue joint. And not all biscuit jointers are as “precise” as one would think. I only use them sparingly now.

Me with two in the shop (PC-one set up for face frame) and one in the truck(dewalt)


-- Real_cowtown_eric

View revanson11's profile


113 posts in 3383 days

#12 posted 07-05-2013 02:14 AM

Geez, I should have read this thread before I glued up a 1” thick QSWO top for the sideboard I am making. I discovered during finishing that I had little “dimples” all along the glue joint, everywhere there was a biscuit. I compounded the problem by using two biscuits per location, one upper and one lower in the thought that if one biscuit was a good thing then two would be even better. Chalk it up to another lesson learned.

-- Randy, Central MN

View Fuzzy's profile


299 posts in 5039 days

#13 posted 07-08-2013 02:56 PM

The “telegraphing” everyone complains about is simply a function of the biscuit absorbing water from the glue and swelling up a bit … AND … of someone surfacing that piece before the moisture equilibrated which would allow the swelling to go back down. If you give it a day or two, the little bumps go away and you can be about your business.

-- - dabbling in sarcasm is foolish … if you’re not proficient at it, you end up looking stupid … ... ...

View SCOTSMAN's profile


5849 posts in 4635 days

#14 posted 07-08-2013 06:51 PM

I got rid of my dewalt biscuit joiner and never missed it. In fact if you have two nice straight edges imho they are more of a hinderence than benefit.Funny when they first came out everyone wanted one, now nobody mentions them anymore.I havent seen anything about them recently have you more trouble than they are worth imho. Alistair

-- excuse my typing as I have a form of parkinsons disease

View Lee Barker's profile

Lee Barker

2172 posts in 3901 days

#15 posted 07-08-2013 08:40 PM

Alistair, you’re closing your eyes to the tasks that biscuit joiners do very well. It’s neither the fault of the tool nor the technology that brings on (potential) issues as mentioned here. It is errors in application.

If we all would truly explore the full use of any woodworking power tool on the market, we would find that each one has a sweet spot, some of which are wider than others.

That said, you are certainly entitled to tossing yours over the fence. But let’s not denigrate the tool without really knowing what it can do.



-- " his brain, which is as dry as the remainder biscuit after a voyage, he hath strange places cramm'd with observation, the which he vents in mangled forms." --Shakespeare, "As You Like It"

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