Continued from part six
The timing gears are supplied as pre-cut blanks and just need finishing off.
First job was to make a collet for the pinion. As cutting four slots is a lot easier than three, I elected to use my four-jaw self-centring chuck.
Some years ago, I made the George Thomas keyway cutting attachment and this made short work of the slot in the pinion. Actually, I can highly recommend making such a device as key slots are so easy that they become the preferred method of securing wheels to shafts and are infinitely better than locking screws.
The big wheel was held the same way before setting up in the mill to drill the pilot holes for the spokes..
Must get a taller mill! This is as high as it goes.
A few minutes with the sawing wires.
And then a couple hours with the needle files and some emery cloth.
I drilled and tapped it 5BA for a grub screw. This was a mistake as I have only found 4BA and 6BA for sale! Will have to make one or make do with a slotted screw.
I thought I had better see how they mesh and drilled and reamed some holes in a piece of steel at the coordinates specified in the drawing. They do mesh but are a bit tight so I shall add a couple of thou in each direction just to give them some slack.
Part eight here
