Notes for making a Glastonbury Chair based on the plans by Master Rhys Terafan Greydragon

Here is what we are talking about.

Materials:

In the UK you can’t actually get the sizes of timber mentioned in Terafan’s plans. However, this doesn't really matter you just need to change the design a little to account.

The timber I used was;

3”x1” pressure treated pine for the legs and the back and side rails.
4”x2” pressure treated pine studs for the spreader
8”x1” plank for the arms
¼” ply wood for the back and bottom panels.
1” dowel. (Make sure this is the straightest one available in your shop. Wickes have better dowel than B&Q in my experience.)

An important thing to note is that timber is not actually the size it says it is. The size quoted from before they dress it, so it ends up being smaller.

The 3x1 is actually 2 ¾”x ¾”. The 4x2 is 3 ¼” x 1 ½” and 8x1 something line 7 ¼” x ¾”. None of that matters except that you need to adjust Terefan's plans accordingly. So with the ¾” thickness of the 3x1 timber above the top rail of the back should be 1 ½” inches longer than the bottom rail of the back and the front rail of the seat rather than the 2” in the plans.

The eagle eyed amongst you will note that I have reduced the thickness of the seat and back panel. Terafan specified ½” ply but I think this is an over design. The 1/4” ply is very strong especially when supported on four edges for the seat and three edges for the back.

Also using 4x2 for the spreader will look a bit weird so I cut mine down to a square section using my jigsaw and tidying up with a rasp.

One of the things I couldn't figure out from Terafan's plans was how the seat and the back panel went in. You need to cut a slot in the side rails, back rails and the top of back, back of the seat.

Techniques.

To make this chair you will need to use a router or be very handy with a chisel. At a bare minimum you will need to cut a slot to take the back and seat panels. The way I did this was to clamp the piece you want to cut the slot in to the work bench then clamp a spare block of timber to the bench to use as a guide and then cut the slot from right to left.

The same technique can be used for any decorative cuts you do. I did them along the edge of the legs as are found in the original.

I also found this technique helpful for cutting the slots in the dowels the best way was to use the router with a 1/4” bit to gradually cut the slot and then square up the edges with a rasp/file. When you are cutting the slot put some spacers either side of the dowel to keep the router in the correct orientation when cutting.

Top tip: When using the router I cut into a test piece first and then took a set square and marked on it the edges of the cut with my pencil. It was then very easy to get the actual pieces in the correct place to cut your slot where you want it. I also found it very hard to see exactly where I was cutting so I found it best to put a mark where the edge of the router will be when you have cut far enough.

Holes

By far the hardest thing to master is drilling the holes for the dowels.

Drilling the holes in the legs and rails is easy enough but if you don’t have a full sized pedestal drill, drilling into the ends of the 4x2s to take the dowels was really tricky. These needs to be drilled square to the end of the timber and I found this hard. In the end I managed to get them done with the help of this tool but even then it was a bit tricky. I threw a way a number of pieces due to not getting this right. I suspect that one of Terafan's super powers is drilling this stuff perfectly by eye.

It is important to note that one good thing about the design is that it is tolerant to a little misalignment. I would say up to about 5 degrees is okay and the chair will go together well enough.

When you are putting this together you will notice that if you drill the holes with a 25mm spade bit and the dowel is 25 mm it will be very stiff to get the parts to assemble. I found that you will need to sand down the dowels for them to go through the holes easily but remember don’t sand where they go into the cross pieces. The small amount of clearance doesn’t reduce the effectiveness of the joints and if you fit the wedges correctly the joint will be very strong.

I used a little glue to make sure the dowels stay in place to ensure that the dowels don't come back out but do this after you cut the slots for the pegs or it will be hard to route the pegs. Or else you could cut the holes a little smaller and use a press fit.

Wedges

To make the wedges I used the router to make a peg out of the 4x1 by removing material down to a ¼ section.

As a picture is worth a 1000 words.

Then I offer the peg up to each joint and mark out the size then cut slightly oversize. Then sand it to fit.
One big change I made to the design is that I glued the seat together. I don’t think this really changes the packability of the chairs but it does make putting them together easier and also reduces the change of breaking the ¼” ply.

Labels

As you almost certainly will not be able to create each joint exactly enough to allow interchangeability of the parts make sure you label everything it will save you much angst as you put the chair together!