Chris,
The bearings are made from 2 sheets of 12mm ply laminated together.
Nailing a few boards to the bench to brace the panels as I cut them.
Basically I cut the design before I cut bearing surface. Starting first
with drawing the spokes on the boards, I first cut a line for the inner
rim surface using a round cutting bit, then I used a bit that cuts a 45
degree angle and worked my way down, trying to leave about 5mm of
meat at the bottom, you want the pie pieces to stay there. Unfortunately
I did a few over cuts here into the spokes, which had to be filled. I then
used a 16mm spade bit to cut the upper ends of the spokes. I then used
a length of straight pine as a stencil so to speak and cut the spokes. I
made the hub using a disc cut from 9mm ply using a hole saw, the drill bit
I use to swing the router off is the same size as the one in the hole saw,
so just tap the bit down until it does interfere with the router and cut
your half circle. I then got the dove tail bit and cut freehand, the top
layer off the spokes with the pie pieces still there giving the router
something to ride on. I then routed out the pies pieces and cut the
bearing surface. With the pie pieces removed I just nailed in the wooden
blocks to help keep everything stable on the final cut.
here are some pics of the process I did. You may find an easier way,
i just used what I had available at the time in thought and tools
regards,CS