FH Dry Build - Magneto Cutout Switch

There's lots of jobs to do on an old bike project - some dramatic, some messy, some tedious, some hardly noticeable. One of these is the magneto cutout, which is a small Lucas 76207 horn button mounted in a folded steel bracket to one of the handlebar clamp studs. It's here:

You'll recall I made some nuts last week - one of these was the locking nut for the cutout button:

The bracket will be a bit of 2 mm cold rolled sheet, but its a bit of an odd shape as it has to appear from under the top yoke, go forward under the handlebar and then pop out between the handlebar and the casquette. It took me three goes to get it right in cardboard:

I made the next prototype in 0.8 mm sheet which I could cut with snips and fold easily:

This looked OK but the switch wasn't quite in the right place:

It took me two more goes in this sheet before I felt confident that I wouldn't be wasting time if I went to the full thickness. Of course, at 2 mm thick it was going to need a bend allowance and it's straightforward to build that in during the marking out stage.

Here's a close up after drilling - you can see the double lines showing the position of the bends. I use a bend allowance equivalent to the thickness of the material - in this case adding 2.0 mm to each bend.

Here it is again, having been cut out with the hacksaw, filed and linished to the final shape:

I didn't take any pictures of the folding in the vice. I was careful to use the smooth jaws, have the bend line exactly aligned with the top of the jaws and to observe the bend forming as I pushed it over, such that the bend was formed between the two bend lines.

That's it. I've added it to the list of small bits to be zinc plated later.