Today has been very productive, even if has been spent on tasks which are not my favourite sort of work. The reason for this can be expressed in three words – MDF, plywood, router. So it has been quite an atypical day at the workbench for me. The purpose for this change in work style has been making the bending form for steam bending the comb of the Apprentice’s Stick Chair. As much as making templates and routing sheet goods to shape is far from my idea of a good time, it is one of the most effective means of making a bending form, so on Saturday morning I took an early morning trip to a local timber yard to stock up on materials.
The bending form is very simple, and comprises two halves which are square on three sides, and curved on the fourth side to match the curvature on the rear edge of the chair. One half of the form has a convex curve while the other is concave, so that when the comb is steamed and clamped between the forms they will persuade it to adopt the desired curve. I do so little work with sheet goods that my ‘shop isn’t really set up for it, and this sort of work always seems to take longer than I expect, mainly because it is a very different workflow and sort of problem solving to the handwork I do 98% of the time. While I wouldn’t want to spend too much time shackled to the router in my dust mask, it is good for the soul to occasionally try a different method of working.
The comb for the Apprentice’s Stick Chair is 50mm wide, and so I made the form out of three layers of 20mm MDF, each measuring 300mm x 600mm. Because MDF does not work well with handtools, I first made a routing template out of 6mm thick plywood which is ar easier to shape by hand. The template was 600mm wide to match the width of the MDF, and I drew a centreline before using a drawing bow to trace on the curve of the comb. While the comb is only 17 1/2″ long (to match the chair) I extended the curve across the full 24″/ 600mm width of the template in case I want to use the same arc for a longer comb in the future. I find it easier to cut a flowing curve by hand rather than on the bandsaw (probably due to a lack of practice for the powered method) and so cut the curve of the template using a Knew Concepts coping saw, before sanding to a smooth curve with Abranet (80 grit followed by 120 and 180 grits) on a hard sanding block.
I then used the template to draw the curve onto all 6 pieces of MDF, and cut a rough curve on each using the bandsaw, making sure that I stayed outside the layout line. Once the curve was roughed in to each piece of MDF, I then routed one layer of each half of the bending form to final shape using a 12mm template bit in the router. A quick check demonstrated that the two halves of the form fitted together nicely, and then I laminated the MDF boards together, using Titebond Original and plenty of clamps. Once the glue cures I will shape the remaining layers of each form using the same router bit, following the curve of the top layer (which I shaped today). This approach makes for an easier glue up, as lining up the various layers once they have been lubricated with glue is far less critical than if all three layers had been routed to the final shape.
While the power tools were out, I also made a pattern of the chair using some leftover 6mm ply. I intend to make this chair again, and already have some ideas for a subtly different version, so having a pattern of the seat shape with the position of the legs and sticks laid out, together with the key angles, will mean less time revisiting my notes and more time making shavings.
With all of the power tool work finished, it was a blessed relief to reach for my block plane and fine tuned the fit of the sticks, as well as easing some of the hard edges of the seat and legs. The chair is now ready for the sticks to be glued in, and the comb to be fitted. Which means that soon this project will be finished and the chair will be in use.