Joints Debate - What to use & when?

[Rebel (Ron)]

I've been up since 4:30am, can't make noise so I've been reading about woodworking. Crazy!! That's not the question. I've read a lot of books, with little hands on experience and have watched shows like the New Yankee Workshop and I was wondering at this hour - given the types of joint methods such as dowel, mortise/tenon, pocket or biscuit, in using one of the these, is it simply a matter of preference or are there legitimate reasons in the use or a particular one. Norm seems to use a different method each week; however, biscuits are most common. For example I have read the biscuits are the strongest when it comes to exterior doors. Maybe I should just go and buy a biscuit cutter, but there goes the challenge and the thrill of using the other choices. There in lies the fun. I think I have answered my own question.

Any way what are your thoughts.

Take care out there.

Ron

[Andy Dingley]

Yes and yes.

There are thousands of joints (I have one Japanese book here called literally "A thousand joints for building work"). Many of them can be used for many different tasks, and almost all tasks can be achieved by more than one joint. So there's a huge overlap, and it's up to you what you use.

Some work better, some are easier to cut, some are more likely to still work if cut badly. There's a famous way to judge the age of medieval buildings by the type of scarf joint used - this joint was simplified twice over a couple of centuries, as successive bouts of the Black Death removed the best carpenters from the trade.

Sometimes you have to use a particular joint for aesthetic reasons. It's not Greene and Greene if you swap those bridles or tenons for invisible biscuits.

On the whole, you should learn to cut something, and cut it well. Then use that. If you learn to make other styles equally well, then your options expand.

[mac davis]

Well, if this was production.job.woodworking, I'd say that you pick the strongest and fastest joint...

Being that we're supposedly doing this for recreation, it's a whole new ball game... I use a LOT of biscuits... but I hope to attain the skill level needed to do many "fancy" joints...

IMO, things like dovetail and tenon joints are no "needed" to get a strong joint, but they enhance the look and exhibit the craftsmanship of the person that made it..

I think a lot of hobbyists pick projects not for what the need around the house or shop, but either what can be made next to learn or practice a joint or the use of a tool... this IS a hobby, and sometimes the worst thing that you can do is get a job done quickly..

*g*

Also being a hobby, I think a lot of the decision on what joint to use depends on who might see the finished work... the more chance of fellow woodworkers seeing it, the more intricate or detailed the joints become... both, IMO, as a showcase of talent and the knowledge that the folks looking at the work will know what they're looking at and appreciate the joinery, where the average person / civilian / non-woodworker might say something like "what a pretty wood!"

[Tom]

Ron wrote:> For example I have read the biscuits are the strongest when it comes to

Where'd you read that? I believe that mortise and tenon joinery is strongest for exterior doors. Biscuits are great for locating pieces relative to one another, but as for strength in something that'll get slammed every now and then, no. Tom Work at your leisure!

[Leon]

Biscuits are great for alignment and they add strength when gluing solid stock to the edge of plywood. Also they add strength when gluing end grain to anything but are absolutely not the best choice in all instances. If you have the room for a mortise and tennon or dovetail joint they will be inferior to those joints. Other than that the biscuits basically are an unnecessary step.

[David]

Would you please provide the reference for "biscuits are the strongest..."?

David

Rebel (R> I've been up since 4:30am, can't make noise so I've been reading about

[Bob]

Andy, that expression did not translate over the pond. Can you explain it?

Bob

[Bob]

Biscuits are a time saver and help line things up. They are not the strongest. However, that doesn't mean they are not strong enough.

Fine woodworking commissioned a scientific test of joint strength in 2001. The author designed a test that would cause joint failure with strain guage force measurements. They directly compared traditional mortise and tenon, round edge floating tenon, straight edge floating tenon, and double #20 biscuits.

The king of the hill was traditional mortise and tenon, breaking at 6000 lb load. The double biscuit broke at 2600 lb load. FWW described this range as "Superior" to "Good". For most of our purposes, any of these work fine. The biggest difference was stiffness. The double-biscuit joint was rated as "moderate" in stiffness, whereas the M&T was "very stiff".

What does this mean? Well for those heavy duty things like a jointers work bench, use mortise and tenon. Otherwise, do what floats your boat. For the inexperienced woodworker, a traditional Mortise and Tenon is slow and tedious and aggravating to get right. A biscuit is fast and a piece of cake. Biscuits are very popular and for good reason.

Bob

[igor]

Where are the metaphor police when you really need them?

[Andy Dingley]

Over the Rockies maybe. No-one has heard of Greene and Greene in the UK.

Web search for "Gamble House" (that's the "Gamble" out of Proctor & Gamble, BTW) and find some pictures. Greene and Greene were architect designers who had a very obvious "house style" in how they did their joinery. Modernist interpretations of classic Chinese forms such as the "cloud lift" line. Usually with deeply softened edges on all parts, even where this gives a visible groove in the surface between two rails.. Dark wood pegged joints, generally cut as either bridle joints or mortice and tenons.

If you make a table with biscuited butt joints and a quick router pass with a roundover bit, you might label it as "In the Greene and Greene style", but it will never look convincing. Lots of magazine plans are guilty of just this.

[Rebel (Ron)]

Tom The book is Practical Design Solutions and Strategies [Taunton] I picked it up a Lee Valley

[Rebel (Ron)]

The book is entitled Practical design Solutions and Strategies [The Taunton Press] page 52-57 and the section was written by John D. Wagner.

strongest..."?

[mac davis]

I think they're cookies in the UK, Bob.. *g*

[Jim Northey]

A double pegged mortice and tennon would be stronger.

Jim

Where'd you read that? I believe that mortise and tenon joinery is

[Tom]

Ron wrote:> The book is Practical Design Solutions and Strategies [Taunton] I picked

Hmmmm. Maybe I shouldn't put so much stock in what a Taunton Press book has to say anymore! Tom Work at your leisure!

[David]

However, the author noted that the M&T would be the better choice, never the less.

David

Rebel (R> The book is entitled Practical design Solutions and Strategies [The Taunton

[David]

[Never Enough Money]

First, I had trouble posting this. I apologize if I have multiple posts....

I'm surprised the "what to use and when" is'nt covered in any of your books. IIRC, Tage Frig discusses what to use and when in his books.

For me: mortise and tenon for carcasses. dovetails for drawers I want to be special; otherwise glued & screwed and dadoed. though mortise and tenon (M&T) for more style (and strength) wedged or pegged through M&T for extra beauty/strength.

Half lap almost never. Mitered joints and any relatives, almost never. Pinned through M&T looks nice and is appropriate if you want to disassemble the piece from time to time.

Biscuit joinery only on plywood and maybe mounting trim on a piece where strength is not a concern. A good rule of thumb: biscuits on plywood or MDF only.

If doing glued up panels, only use biscuits as for alignment and don't glue them. If you glue them the moisture in the glue causes the wood to swell slightly so that when you sand the top and it eventually dries out, you have barely noticable (but noticable) little valleys.

Remember to make your joints so that you glue long grain to long grain.

I think dowels, wedges are pretty when you use a different color wood. Dovetails ar enice when light and dark wood are mixed, too. For examlpe a dark drawer front with light sides.

[Never Enough Money]

NOt sure which expression..."bridles" or "Greene and Greene". If the latter, please see

the former, I also don't know what it means.

[Rebel (Ron)]

Thanks for your response. What can I say about the "what to use and when" it was 4:30am. According to 'the book', 3 biscuits are the strongest (side by each) followed by 2, then M&T. However, I don't plan on making a door or lawn furniture. It's furniture for my den and a table for SWMBO, when the shop is finished - my winter project.

Take care