24 minutes ago, kmealy said:

My first use was to butt join vertical and horizontal parts of a 7' tall bookcase.  To my amazement, it was very sturdy right out of the clamps.

I've always been reluctant to confess that I have made cabinet doors and face frames this way.  Once, I dropped a door and it broke - the wood split but not at the glue joint.

11 minutes ago, JimM said:

I've always been reluctant to confess that I have made cabinet doors and face frames this way.  Once, I dropped a door and it broke - the wood split but not at the glue joint.

Follows my rule: If it's strong enough for intended use, it works.

 

Biscuit (AKA Plate) joints were developed in Europe post WWII, and I always assumed it was for a quick and easy way to rebuild using sheet goods after the war's devastation.

 

https://en.wikipedia.org/wiki/Biscuit_joiner

 

I sometimes chuckle to know that at one time, Chris Schwarz (who is now a traditional hand tool guy) once wrote an article on making a jig to hold pieces when making biscuit joints.  I think his boss probably forced him to do it.

I used bisquits a few times, I remember one time I set the bisquit close to the short grain edge of the panel, then raised the panel, and cut down to the busquit, DOH!!!!!! 

Been a long time since I used em, I don't know if I have my Dewalt plate joiner even anymore, I may have given it away. Another of the few times I used it, (not a slam on you Keith, and don't wanna make ya moan) it worked excellent for aligning long boards for long grain glue ups. Loved it for that.

 

16 minutes ago, John Morris said:

Another of the few times I used it, (not a slam on you Keith, and don't wanna make ya moan) it worked excellent for aligning long boards for long grain glue ups. Loved it for that.

 

I think they would help if the boards are really warped, but because the biscuits are slightly undersized and swell when glued, they don't give an exact alignment, but close.   I prefer to use cauls or other methods.

13 minutes ago, kmealy said:

slightly undersized and swell when glued, they don't give an exact alignment, but close.

True Keith, reflecting back there was still a little bit of drift when tightening the clamps. 

I shops really didn’t take to the biscuit. Many were using dowels and used them for many things. Then pocket holes came and the biscuit jointer got caught in between.

The custom furniture shop I worked for that had a show room had a piece in it where they had made a top and run it through the widebelt as soon as the glue was "dry".  Came out fine, but little later you could see biscuit shaped dents in the surface - once the moisture from the biscuit glue dispersed throughout the surrounding wood, the area immediately around the biscuits had shrunk back.  Same thing probably happens to some extent with simple long joints - leave it a couple days before surfacing  

 

One thing I did use biscuits for on and off in that shop was long miters in the posts of an armoire we made.  These days I use splines for that, but back then the shop preferred to biscuit them.  Both methods work.

Edited March 5, 20251 yr by JWD

I remember when Norm Abram was endorsing the biscuit jointer on his show. Woodworkers all had to have it. Later he complained about the biscuits expanded after completion. Everybody tried to sell theirs..

 

I will show other uses for the biscuit jointer on some of my home projects..

 

I have many tools that sit, cost nothing to sit  but I find uses for the: as time goes on..

Edited March 6, 20251 yr by BillyJack

23 hours ago, kmealy said:

Follows my rule: If it's strong enough for intended use, it works.

 

 

 

That point is often overlooked. I'm always interested in these "tests" of joint strength and which is the stronger joint....but the truth is that in most cases, most of the methods are adequate. I still use my biscuit joiner quite a bit and really like for miters as well as putting hardwood on the edge of plywood. I do the hardwood thing once in a while for table tops where the field will be plywood and a hardwood border that mitered in the corners. But when I was first setting up this shop I needed some shelves quick, and didn't have my big tools set up to run yet. I butt jointed a plywood box using biscuits and hung them on the wall, it was supposed to be temporary  but there still on the wall 7 years later with quite a bit of weight on them and no failures. Then there's the guys who buy a Domino and discard the biscuit joiner. Well I have a domino (a second hand well used one) and I kept the biscuit joiner. I will say this, after Festool brought out the 4MM cutter and tenons it's fair to say they are a replacement for the biscuit joiner; but it's still at 5 times the price.

There trying to replace a M&T with a Domino. It’s a nice tool, but it ain’t no M&T..

Joints.  When I was a student the instructor of the first workshop class had us draw up at least 10 different joints.  Those days there was no internet so the college library severed as a source of ideas.  Not sure of the book I found but of course myself and the rest of the students complied and we all turned in a set of drawing of wood joints found in assorted books as reference.  Some common joints are obvious ways to connect two wood pieces, but others are rare enough that I doubt anyone in my class used them in their furniture projects.  Despite having drawn up some joints we all still needed some initial advise from the instructor when proposing what we wanted to make. The only value of the drawn up joints was as a reference for type, but not sizing and strength and appropriateness for each unique design.    Four years later I was teaching the same class, and realized that as a reference a box of made sample joints would be as good of a reference if not better since the sample could be examined and usually taken apart to inspect. To "feel" for strength.  To spin around and view from all angles.  To question about how it was made, what tools were used, etc.. 

My sample box grew over the years as I added more variations as reference.  When we added a CNC to the shop I had to start a second box with CNC cut versions of common joints, as well as original/unique joints I came up with that were impractical to make without a CNC.  Every semester there were several times when I could refer to a sample I made to help a student understand how it might help them assemble their project parts.  Often it was a student in another section that came for advice and a look at joinery options in the box. 

The joinery assignment evolved into a project the students took interest in and taught them the use of several tools as well as how to make several common joints in the context of a project.  The Joinery Box. Not about a box.   

4D

This a book that has been in my shop for as long as I can remember. It was before the age of mechanically produced joints ( routers,mortisers etc) and I can’t remeber who actually gave it to me. Probably my father or possible my grandfather. 
Paul

Biscuits. I first became aware of the Lamello machine around 1985 or 6. At that point my shop was completely dedicated to building houses for a single architect who was very popular in the Carmel /Pebble Beach area. For his houses we made all windows, doors and cabinets and pretty much everything interior. These were extremely high end homes. At the time they were considered “art grade”. We ordered a Lamello and started playing with it and didn’t actually use it in projects for probably six months or so. George ( the architect) spent a lot of time in the shop in those days. He was intimately involved with every facet of the project and ultimately became a good friend. One day we were playing around with the Lamello and he was there and questioned the strength of the joints we could produce with it. He also had a structural engineering background. So we decided to build a full size interior door out of 8/4 alder and send it off to a lab in San Jose to have it tested. We put multiple biscuits in every joint using 1/4” plywood as spacers to raise the Lamello incrementally. The lower horizontal/vertical joint had twelve or more biscuits in each joint. Back then we were using Weldwood glue, the brown powder you mixed with water. So we made it and took it up to this lab where they put it in a press to see what it would take to break the joints. The end result was the door exploded into pieces but all four joints remained intact. It was more of an academic exercise because I was always worried that although the joint was obviously very strong the biscuits would withstand the years of the expansion/contraction forces so we never actually used it in making doors. 
Paul

We added 
"the Joint Book", by Terrie Noll to the shop library where I taught.  "A Complete Guide to Wood Joinery" it claims. First publish in 2006. 

I've just scanned through my copy and re-affirmed my initial conclusion that although it is very thorough it is limited to what can be done using hand tools/chisels,  and for the most part connections between parts at 90 degrees to each other. A couple simple angled versions were shown including and angled half lap and angled mortise and tenson.  The latter could not be duplicated using a CNC, although a slight variation could be.  Far more is possible with a CNC configured to handle clamping parts at angles or compound angle under the spindle.  Improved variations of classic joints also become "easy" to cut using a CNC. 

4D 

Posts unrelated to the original topic have been hidden. Thanks for a great topic Keith! Back on track!

In my re-reading of "vintage" FWW (#148), I ran across yet another joint test.  Again, one type of joint (butt as in a rail and stile) and one type of force (diagonal to the corner)  But some interesting results.   Round-shouldered loose tenons (e.g., Domino) are somewhat weaker than integral tenons, but of course much faster to do.  And a double biscuit joint, while about half the strength, is "not just for alignment only."   As I've said many times, it might be strong enough for its intended application.  Would I use it on a chair, no.  Is is strong enough for a cabinet door, probably, unless your 8 year old swings on it every day.

 

 

On 3/3/2025 at 10:37 AM, BillyJack said:

If you build something correctly, it shouldn’t be under any stress to matter. A chair can differ..

We build about 30 tables a week at the furniture bank.  One or two come back every week with the legs broken off during delivery.  As was my experience, "transit damage" is often the most stressful time for a piece.

Cabinet frames, doors with panel in the middle, etc, won't fail as easy a simple corner joint.  The load on a frame or door is resisted by all four corners and the door panel which wants to stay square.   So multiply the strength result by 4 at least.  More if it has a panel in the frame. 

4D