Small stool in style of Japanese bath stool

In between other jobs I had some spare wood left to make a small stool for my grandchildren. I wanted to try another design so went for a stool with "through angled tenons". These joints I found quite challenging to do with hand tools but I persevered and so I include a few thoughts from this project here.

I made the top and legs from a 3.5 cm thick pine board. The finished stool was 36 cm long and 22 cm wide and the height was 24 cm. Pine isn't ideal for detailed joints because of the course grain and so takes more care to work and sharp tools. I used a section of 2 x 2 inches to make the stretcher connecting the two legs.

Stool after making the joints. Surface preparation (planing and sanding), preparing clefts, gluing and treatment yet to do.

The legs were set at an angle of 10 degrees from upright hence fixing the angle of the mortice and tenon joints on the two legs and stretcher. I set the angle on an angled bevel marker and this remained fixed for the entire job. the construction involved:

1. Marking out the two legs and sawing to shape. This can be just rectangular or truncated pyramid as shown. I also made a 5 cm cylindrical cut in the middle of the bottom of each leg and so made four balancing points for better stability of the stool. 

2. I decided to make two mortice and tenons on each leg to join them to the top of the stool. Basically the top was 12.5 cm wide and each tenon was 2.5 cm wide. The length of the tenon was about 5 cm to allow them to protrude out of the top so that the beech wedge could be added when gluing and then sawn/planed to the meet the top surface.

3. The most difficult part of the construction for me was cutting the mortices in the stool top. For this I made a small jig to clamp to the top and use as a chisel guide to get the correct angled mortice  (again 10 degrees).  I found that if I clamped the jig firmly to the top with a piece of plywood on the underside of the top, I could cut the mortice from one side right through to the plywood base. This worked well for all the joints. I made the jig by sawing/planing the correct angle on the face of a piece of beech and then cutting into three sections and then gluing together with the centre piece off- set.

Beech jig for cutting mortices. The face is angled at 10 degrees to the vertical and the width matches the tenons. The front "prongs" are also angled.

Finished stool after two coatings of Danish Oil. A further coating of clear polyurethane was applied after a couple of days. Now in full use by grandchildren.