Today I made some improvements to the wheel rim jig, I marked out the outer rim using a transom arm protractor. That is, a protractor that is made by fixing a batten to the centre of the circle and then rotating the batten through 360 degrees marking a line at the end of the arm. This gives you a circle. Then I cut along the line with a jigsaw to leave me with a circle. I still need to rasp down some high spots and fill some low spots, but it gives me the shape that I need.
I drew a line through the centre of the circle to give me the starting point. This line passes through the centre point in the circle, the line gives me 0o and 180o. From there, I marked off points at 36o, 72o, 108o, 144o and back to 180o. As the circle is divided by an even number, I can simply draw a line from each of these five points to the opposite side of the circle to give me 10 equal divisions.
Next, I marked out a point on each of the division lines about 1 and a half inches back (2.5cm) from the perimeter and drilled holes through for the jig clamps. Turn the jig over and clean up the slight tear-out from the drill and, presto, a wheel rim jig is made.
You should be able to draw a straight line between each opposing pair of jigs and they should all meet in the centre of the circle.
I may need to fix another layer of fence palings to the jig to make it thick enough. Otherwise there will be a tendency for the laths to warp because one side or the other of the clamp will be off-set.
The threaded bar that is used in the clamp has been left quite long so that I can have enough clamp to make a rim up to about 15cm.
In the top photograph, I have put the topmost clamp all the way through and brought the next two clamps all the way forward so that I can use the clamp as a hanger to hang the clamp off the ground. I have also got a hole drilled through that was at 45o from the first hole. This will be where I can hang the jig up in my workshop. Hanging the jig means that I can have bench-space cleared up while I wait for the epoxy to cure. The epoxy that I will be using is a two-part marine epoxy. This epoxy has a little bit more flexibility in it than other woodworking epoxies and the wheels will take a bit of bumping around when under load.
One of the reasons that I have made this jig with 10 jig clamps is that I intend to make my wheels with 10 spokes. The clamps also provide me with a guide for making the spokes.
Anyway, that’s it for today. I hope you enjoyed it.