As promised many months ago I’ve put together a walkthrough of my arm rest coffee table project. I did my best to capture as many of the steps as possible, but if you have any questions about what I did let me know in the comments.
Selecting the Wood
I’m still not very knowledgeable about different types of wood. My current strategy is to go to my local lumber yard, wander around looking at the smaller pre-cut pieces and pick which one looks to best to me. Once I select the type of wood I look for a board that isn’t badly warped, cracked, or has knots that would interfere with the project.
For this project I ended up purchasing a piece of paduk that was a decent length and thickness. When cut or sanded paduk has a nice orange color, but over time and exposure to sun it darkens to a rich brown.
Prepping the Wood
The board I bought was about three feet long, so I needed to cut it down to the appropriate size. To figure out the proper size I held two hardback books on either end of the arm rest and measured the distance between them. I then took some measurements for how low down the arm rest I wanted the sides to go. Finally I added how deep the dovetail joints would be (ie how high above the arm rest the sides would be), I based this on the thickness of the wood. The “formula” is simply: wood side a + wood top + wood side b + thickness of wood top x 2
This is also where I made two mistakes.
My first mistake was not pressing the books tightly enough against the arm of the sofa. I was worried about making the fit too tight, but this caused the piece to be a little loose on the arm. The second, and very annoying, mistake was cutting the wood into 3 pieces too soon in the process. My reason for doing this was so I could plane the two sides thinner than the top. The extra effort of planing, sanding, and verifying all the proportions matched was not worth the extra effort. (And to add insult to injury, after I finished the piece I decided a thinner top would have looked better).
This next picture isn’t very important to the process. I was just very pleased with how straight and accurate my cut was. All the practice I’ve been putting into learning the basics was finally paying off.
The next step was making sure all the pieces were square, which was the hardest part of the whole process. It was hard because I don’t think my shooting board is 100% square, and shooting end grain is very difficult. Also, at this point in time I hadn’t learned how to properly sharpen my blades, and I didn’t have the proper sharpening tools. A lot of elbow grease and time was required to shoot 6 end grain sides. The time and effort was definitely well spent though, without having square boards the final piece wouldn’t look nearly as nice.
This was the scariest part of the whole process. While I was getting better at making dovetail joints, I had only done it on small scrap pieces. My designed called for a lot of joints, and if I screwed any of them up I would have had to start all over.
I tested out a few different methods to make sure the joints were all level, such as clamping a board to the base of the joint before cutting the waste out (pictureed below). The best method was, unsurprisingly, what almost every woodworking site suggest, starting with a marking tool and then going slow and careful with the chisel and mallet.
After slowly and carefully removing the waste the tails were looking pretty good.
Now that the tails were finished it was time to mark the pins and waste sections.
When I was doing a test dry fit of the boards I was having a very hard time figuring out which sections were not fitting properly; there were too many joints to feel where exactly it was getting stuck. This is when I finally realized what a few blogs and videos were trying to explain about putting a small notch in the pin.
On the top edge of each of pin use your chisel to cut out a small angle, creating a funnel for the tail to slide into. When you do this you can easily see which tails are fitting into the wedge, which are not, and which pin is getting compressed once the tail is sliding in. Once I figured out that technique the whole thing came together a lot easier. (I was planning on planing the pins flush afterwards anyway so a small notch wasn’t be a problem)
The final result was pretty good, but not perfect. I had to use some saw dust mixed with glue for a few small gaps, and make two small wedges for two wide gaps. After the fixes it looks half way decent. I need a little more practice using the glue and saw dust though. I wasn’t able to get a good even spread across the gaps.
Cutting the Marble
I had never worked with marble before, I wasn’t even sure where to get any. I had initially looked for a piece of marble tile at Home Depot, but wasn’t able to find the proper size. In the end I found a long piece of marble at a used goods store and bought it for 50 cents.
I set up a simple guide for my small power saw to cut a square section off. I was surprised how easy it was the cut through marble.
I’ll spare you the details, but I wanted to marble to be hexagonal shape, but I didn’t have a compass or protractor; I had to figure out how to make a regular hexagon with only a ruler. After a lot of internet searching and trial and error I confirmed that geometry does indeed work. I drew out the figure on a piece of paper, and tapped it to the marble square and started cutting.
I also unfortunately learned how porous marble is. I had used a blue pen to mark off a few measurements, and the dots were quickly absorbed into the marble.. It took me a lot of sanding to get rid of them. In the future I’ll stick to wax pencils which were easy to clean off.
The last couple of steps involved refining the shape, and making sure it was roughly square. To do this I clamped a file to my square and rubbed the marble piece back and forth.
Inlaying the Marble
This is one step I definitely didn’t capture as many pictures as I should have.
Given the limited number of tools I had (have) I was expecting inlaying the marble to be very difficult, or at least difficult to make it look good. I used an extra piece of paduk as a test and after a little trial and error discovered it was actually pretty simple to get a half way decent inlay. All I did was hold the marble steady while I cut a shallow outline, then carefully used a chisel (bevel down, cutting across the grain) to slowly dig out the pattern. (aka, all the steps I didn’t take pictures off). Since my hexagon shape isn’t perfect, I also used a piece of tape to mark the proper orientation, which saved me a lot of guess work every time I needed to do a test fit.
The only problem I was having with this method was getting a flat surface on the bottom that was level with the top. I probably could have achieved the desired results with a bit more practice, but I had been meaning to purchase a router plane anyway. Once the router plane arrived I moved on the real piece and the inlay came out looking great.
Testing the Wood Polish
I went back and forth if I wanted to use polish or lacquer on the final piece. After a few tests I decided to go with polish. I liked how it really highlighted the color and grain of the wood without giving it an overly shiny appearance. Plus, I haven’t worked with lacquer and had done enough learning for one project.
From left to right on scrap below: un-sanded, sanded, sanded and polished.
Final Piece and Comments
Overall, I’m very happy with how my first woodworking project turned out. One change I’m going to makes is gluing some thin rubber matting to the inside so the piece doesn’t move around as much on the arm rest.
Also, now that I’ve finished the question is “what next?” Technically this project came about as a test before making something similar for a friend. That was over a year ago, I should check to see if she still wants / needs one. If I do make this again would change two things 1) make all pieces a uniform thickness 2) use fewer joints. Both of those changes will save a lot of time, and I think make it look even better.