I've never really tried mitre joints before and doing them by hand sounded daunting. I came across an article in an old magazine showing a jig that can be used to make relatively quick and accurate mitre cuts. Now whilst my execution in terms of making the jig and the resulting joint isn't the best ever, I feel that in more skilled and knowledgeable hands it could be a wonderful tool. I am however pleased with the result considering it was my very first mitre and I think with a few adjustments and a little practice I can start to make some very accurate cuts indeed.

I have a video up on YouTube showing the making of the jig as well as the jig in action, its very satisfying to use! More detailed instructions will follow.

Step 1: Tools and Materials

Tools

- Pencil and rule

- Hand plane and block plane

- Combination square

- Knife

- Tenon Saw and Rip Saw (or table saw/circular saw etc.)

- Clamps

- Hand drill and 2mm bit (or power drill)

- Screwdriver

- Coping saw

- File

- Small, sturdy clamp to hold jig in place

Materials

- Length of hardwood 22cm X 3cm X 3cm (approx.)

- Small piece of plywood (or other very flat material, perhaps plastic?)

- Glue

- 4 X 20mm screws

Step 2: Marking Out the Guide

I used sapele to make the guide because not only is it a hardwood but also it was what I had available! I made sure that all the sides were square first, planing down a little here and there to adjust it. Then I cut it to length, around 22cm long. I marked the 45 degree angle 15mm in from one side. There's a fine line here and I think I got it about right but I guess its personal preference. There needs to be enough of a flat surface for the sole of the plane to sit on but at the same time, if you make that flat surface too wide, you'll cover up too much of the blade.

After the whole thing was marked up I then went over the lines with a knife to try and get it as accurate as possible when cutting.

Step 3: Cutting and Shaping the Guide

This was the hardest part of the build without question, making a 45 degree angle along the length of a piece of wood with hands tools is rather difficult! I started by cutting the waste away with a saw first, starting with a tenon saw and then moving on to a Japanese Ryoba. I then clamped the guide into my vice and planed away at the waste until it met the knife line. You could also use a file or even a chisel. (You could of course also use a table saw or circular saw)

Step 4: Attaching the Guide to the Side Board

The side board needs to serve two functions; first it needs to be at a right angle to the piece of the guide that rests on the sole of the plane. If its off by a little then the mitres wont be 45 degrees. Secondly it needs to be able to be clamped firmly onto the plane easily and not budge.

I started just by gluing the guide to the board and then screwing the board to the guide from the other side. After that it was simply a case of lying the plane on the guide and tracing around the plane onto the side board. I cut around the line with a coping saw and smoothed it down with a file. I don't think its necessary to have the board match the side of the plane but I thought it might make it easier for me to hold and control.

Step 5: Testing the Jig

After drawing a 45 degree angle on the end of two boards I had to use a block plane to take one of the edges off. This was to ensure that when I passed across the board with the plane the ends didn't blow out. Upon using the plane and jig I was really surprised at how quickly material came away and how easy it was to stay on track.

Step 6: The Result

I think if I took myself out of the equation and substituted myself for a more skilled and knowledgeable woodworker then this would be an incredible success. As it was I was rather pleased with them for a first attempt. I think the combination of the wood I planed down not being entirely square, having to keep adjusting the lever on the plane to get the correct angle and also having made the long 45 degree cut by hand made it so that there could be slight errors.

I would call it a success though and I think with a few slight adjustments it'd be a wonderful way to make accurate and clean mitre joints. I'm sure in the future I shall be posting a box with mitred corners on Instructables made using this jig!

Thanks a lot for checking that out, as always any comments or criticisms are welcome.