Elaborated wood joints

[Osvaldo Cristo]

I am an amateur woodworker. Not a professional. Not an artist... but I love to create things with my own hands, included wood working.

On the other hand I am also an Engineer (OK, nobody is perfect... ), so I try to separate reality from passion... I can understand most of us here in the forum have a passion for wood working but I think we have to know where is the border between both of them.

One case I would like to bring is wood joints. I read a lot about elaborated wood joints and their advocates elaborating about how important they are for a strong construction, but from my own experience most of them looks me overkill.

I would like to share with you a couple of examples where simple and fast joints demonstrated to be very solid and durable.

The first one is the drawers I made to our home and they are distributed by the kitchen, library, laundry, dorms and bathroom: they have a raised panel front but the box is made from 12 mm (1/2") plywood butt jointed, yellow glued and reinforced with a few brad nails. I guess we have around 30 of them spreaded in the home. Not a single one presented any stability problem. Rock solid up to today after 25 years of intense use. They resisted a couple of toddlers up to their adulthood, also... BTW I had to change two or three sets of Blum rail guides in that time as they failed...

Another example is the bookshelves we have in the library, also made 25 years ago. I had on the occasion a number of books to bring to our (then) new home and just a very limited amount of time to construct something to house them, so I went to a "temporary" solution of very simple book shelves using 20 mm mahogany covered plywood. I decided to use only screws. Each shelf is 732 mm long and supports something between 25 to 30 kg of books. Only two 45 X 4.5 mm wood screws support them from each side. No glue. No grooves. No sagging or other problem at all after 25 years... so they turned my "definitive" solution. I have 48 of such shelves fully loaded. (bellow I included a few pictures of them)

Bottom line: Although I love elaborated wood joints and the artistry to make them, for most applications I have found I do not need them for the sake of sturdiness. Elaborated joints for decorative purposes are another history...

I would like to listen your experience using simple joints against the more elaborated ones.

All the best!

[Brian Holcombe]

Wood joints exist for a few reasons, one is to create a structure and the second is for that structure to keep the wood from distorting. The structure self-sustains if it is properly engineered.

Advanced wood joints are also made to self-join and not necessarily rely upon glue. Elaborate wood joints are often used in structures which they cannot or should not be glued. They must rely upon the wood and wood properties. Can you imagine gluing a house together? Perhaps today that is the case, but in many cultures a house is something that needs to be repairable and so demountable joinery is required.

Glue fails eventually, now a good engineer might argue that a given thing should only last an intended lifetime. However those building outside of this mindset may feel that the material, which takes hundreds of years to grow, should be respected and utilized over the lifetime it can provide as a material. Hinoki cypress, as an example, can last many hundreds of years and engineering its structure to fail in 80-100 years is doing that material a disservice.

Putting a screw into end grain is not a substantial joint, it's likely to fail if any real stress is applied. Cupping in the wood can destroy the joint. If you are joining that structure a basic joint is a dado, it is also insubstantial but it improves upon the screw because it positions the board. This aids in assembly. To further detail this simple joint you can use a sliding dovetail, this is a substantial joint because it provides a batten to the adjoining boards while keeping the board in place.

A sliding dovetail is not complicated, but may be considered as such by those who are unfamiliar with them.

[Pat Barry]

Regarding the bookcase shelves, the situation is mostly just a static load. If you haven't experienced sag then the load of your books didn't exceed the material properties of the shelf material. If the shelves were to fail (from overload), most likely they would shear off the wood around the screws (try climbing up the shelves and see what a significant load will do. Regarding sag, most folks would have some additional structure on the front of the shelf (laminated on piece of 1x2 on edge for example) to add rigidity.

Now if you were moving your bookcase frequently, with a load (maybe even without) you would see failure in your screw joints due to flex fatigue, racking, twisting, etc.

[Wayne Lomman]

Yes you are correct that in many cases, elaborate joints are superfluous. It's a bit confronting for many woodworkers to hear this. Having spent my working life so far in construction, furniture, joinery and engineering, I have learned that joints should be what works. I have fitted out banks, government offices, homes for all budgets, mining camps etc. Everything supporting static loads is butt jointed secured with steel fasteners. Done correctly and with proper reference to material properties, this lasts for decades.

However, steel fasteners are a poor substitute for good, elaborate timber joints when dynamic loads exist, such as with chairs and movable furniture. The joint structure and glue are required to keep the members immovably in position because as we all know, the barest minimum of play in a timber joint causes the timber in that area to compress which loosens the joint etc etc.

My advice to all is to do the very best you can with the resources you have, both your skills, your equipment and your timber. Don't be afraid to work with a variety of materials and use the full range of joints. Do not set limits either high or low on what can be done. Our kitchen chairs are 32 years old. I made them out of offcut framing pine and offcut ply for the seats. It's all I could afford. But I did the joints properly, carved the top splats and painted them gloss white. My wife won't part with them It will be your workmanship and that makes the difference. (see, still can't hide too many years as a lay preacher...) Cheers

[glenn bradley]

I would like to listen your experience using simple joints against the more elaborated ones.

All the best!

If I am using plywood for structural pieces (case dividers, drawer dividers, etc.) I will use things like pocket screws or dowels. I think you will find a lot of cabinetry for kitchens, baths and utility rooms use pretty basic joinery and things like brad nails for constructions of ply, melamine and other movement-stable materials.

For constructs that I know will face movement over the seasons I use proven methods that I don't really think of as elaborate . . . frame and panel, tongue and groove, sliding dovetails and so forth. For show (I do a lot of Greene and Greene influenced stuff) I use elaborate joinery as it is on display as you mention.

[Mike Cutler]

I first started out in woodworking in 1970. I know, a zillion years ago. I was 11-12, and in the 7th grade.
The teacher at that time always maintained, and insisted, that a finished project should have enough mechanical strength, in the joinery, to hold it's basic form, without wood glue, or fasteners. I still build this way today. I know that glue is stronger than wood today, but,,,,,,,

I personally do not like exposed joinery beyond what is absolutely necessary and cannot be hidden. Dovetails, just of the sake of dovetails, doesn't do anything for me. They have to have a structural purpose. I guess my one exception would be drawers. I do think a dovetailed drawer looks nice, and it's also a very strong joint in this instance.

As far as your screws and nails are concerned. The same teacher taught that a screw, and a nail, are just disposable clamps. There's nothing wrong with mechanical fasteners. They're stronger that the wood also.

[Ron Citerone]

<p>
I built all of my furniture when I was a fresh out of college as an Industrial Arts teacher. I was in my twenties and had a basic shop and a new house and my wife and I had no money and no furniture. While I built using decent techniques I made some design/artistic/structural mistakes, my furniture, which fill my house to this day held up very well and looks good. Presently, I over design just because it makes me feel good! No more cope and sticker doors............haunch mortis and tenon. No more overlay doors and drawers..........flush. No more simple base molding...........splined/mitered ogee feet. I pay great attention to matching grain on panels and try to avoid glue ups when possible. I try to match grain on pieces with more than one drawer. If something isn&#39;t right I rework it. On each piece I now try to add a design feature that I haven&#39;t tried before. I search ebay for vintage unique brass hardware. It makes me feel good. My last 2 pieces, although smaller than some of my older work are my best. I gave them as wedding gifts for my daughters. My daughters might not know what they have, but it makes me feel good. My 2 cents. Great topic and great comments so far.</p>