Woodworking with Bob: the Mortise and Tenon Joint

Early on Saturday morning I grabbed some coffee, hopped in the car, and headed for Frankfort. For a long time now I’ve talked with Bob about woodworking, and at several turns he extended an offer for me to help him do work on the house. I finally made it a point to set up a time, and decided to spend a Saturday working with Bob.

A view of the workshop (which is on the second floor of the garage).

A quick note: while I took a fair number of photos, I spent a lot of the first few hours just observing and asking question. I didn’t break out the camera until later in the day, as I worried the whole documentation thing would get in the way of the whole learning thing.

Bob suggested we build a small table as a project, and so before we did anything… we sketched out plans and dimensions. He also created what he called a “cut list,” which is there on the top right. A cut list tells you what dimensions you need for each piece, and how many of each piece.

All the wood we used ended up coming from the wood from a shipping crate. I believe this came from a job that Bob did, involving a large air conditioner for a hospital. All the wood we used was salvaged from that particular crate.

After cutting wood for our legs, we came over to this guy, who I believe is called a “joiner.” I’m not entirely clear on why it’s called this, but that’s what I remember. See where the metal is in the center (it looks like a flag)? Underneath that cover is a rotating blade. To ensure that we can get good right angles for our wood, the joiner is step #1.

Using the table saw to cut down some wood to size (for the legs).

This was really interesting: in the middle there is a jig that Bob made. The angle of the jig is adjustable, and can be increased or decreased as needed. When used with the wood we’re cutting, the jig allows us to cut into the wood at an angle, and allows us to create a taper in the leg.

The main lesson for today was about the mortise and tenon joint. Connecting each of the legs together will be an “apron,” which will fit into each individual leg. The lines indicate were the apron will line up with the wood, and the smaller “X” within the lines indicates where the tenon will go.

Using a mortiser, I created the mortises in each leg. In the end, I think I didn’t make these as clean as I should have, as we ran into some difficulty when putting everything together.

I forget what this particular contraption is called, but it looked pretty impressive. Here, Bob is aligning things and cutting out the apron pieces (and the tenons that need to be on each side).

Partly there.

The finished tenon.

This is called a planer. I’m still a bit fuzzy as to the difference between the planer and the joiner, but I think it comes down to this: while the planer and joiner both smooth down surfaces, only the joiner will give you true right angles. The planer cuts from the top, and as a result will only be as accurate as the bottom of the wood you’re feeding in.

These are the pieces of the actual table top. I had incorrectly assumed that for the top, we’d just use one large piece of wood. When I asked Bob about this, he told me that if we did that… the wood would naturally bow and flex, and would end up curving eventually.

Instead, using three smaller boards and attaching them together provides the same surface, but increases the strength. Since each piece is up against another, the actual movement of the wood will be lessened, lowering the chance of the wood bowing.

I forget the name of the tool, but it was a handheld device that was designed specifically to cut the grooves you see in the side of each piece here.

To connect them, we used some wood glue and some biscuits.

Putting wood glue over each layer, and fixing in the biscuits.

Throwing a few clamps on the table, with all four legs and the apron connecting each one. At this point in time, I was amazed to find that it was already 2:30 PM. The time really just flew by, and it felt like I had just blinked and we were already in to the afternoon.

As the glue set, we went downstairs where Julie had made us hotdogs for lunch.

Here’s one bit that I’ve still yet to fully wrap my brain around. In order to attach the table top, we went about creating a dado. Essentially, this means we cut a groove into the apron with the goal of taking another, smaller piece of wood… slotting it into that grove, and then drilling from that small piece into the table top itself.

This is sort of backtracking, but earlier we cut the dado into the apron (it’s that thick groove, running along the top).

Here’s the small piece of wood we’d be using the slide into the dado, and to eventually screw in to the table top.

The wood pieces, slid into place and about to be attached to the top.

The finished table!

At the start of the morning, I was under the impression that I’d be helping out Bob with some of his projects. But he ended up stepping me through this table project, start to finish. I really wouldn’t say that I made this table – I’d say that I made maybe 20% of it. But I touched nearly each piece, and that feels pretty good, looking back on things.

Bob was incredibly patient with me, and at several points I had to ask him to go back and explain a particular concept to me. Most of the individual steps made sense to me, but I had some difficulty threading together how steps a, b, c, d, and e led to a particular piece or strategy.

In hindsight, I’m glad to have gotten a more thorough walkthrough from Bob. A lot of my learning is also happening now, as I’m looking back over the photos and trying to remember the steps we took.

Interestingly, a lot of the math involved is similar to designing for the screen. The process of measurements and determining dimensions is very close. I remember how Ben used to work construction, and he talked about how that background helped him when he transitioned to building sites with HTML.

I learned a lot about woodworking today, and had a fun time trying to learn a bit of what Bob knows. Instead of seeing a whole room full of complicated machines, I have a slightly better feel for how each piece functions. It’s pretty incredible to think of the possibilities of what could be made, as there just seems to be an infinite number of things and combinations, given these tools.

Bob mentioned that next time, we’d pick another project and he’d teach me another type of joint. I’m looking forward to learning more, and to me trying to recreate this table entirely on my own. I think I’m slowly picking up things, helping and observing and asking questions. But there’s a part of me that feels like I just need to make about 20 more of these tables, and then I’ll start to get these concepts a bit more under my belt.