I'm following this great post to arc my new rear brake linings:
https://www.a7a10.net/forum/index.php?topic=7252.msg50596#msg50596for my question, the important bits are:
Assemble OS shoes onto backing plate, but replace the shoe springs with turnbuckles; I make my own (refer to pics below). Put 0.010" - 0.015" shim packing between each shoe and the actuating cam....
Do up the turnbuckles tight; this locks the shoes square against the cam, and the fixed pivot. The fixed pivot should be adjusted out most of the way, so plenty of adjustment remains.
Make a dummy mandrell same size as axle, and some sort of custom nut, and install (do up tight) the backing plate. When re-using the mandrell, set up in 4 jaw chuck, to no more than 0.001" run-out.
OK, so i've made the turnbuckles, shimmed the cam end and got it spinning in the lathe on the rear axle with spacers and a live centre at the tailstock. currently about 2 thou runout on a 3-jaw check, (i'll try for better). but 2 questions:
1. the brake plate flails around quite in both dimensions. i guess its not flat and also out of round by ?20 thou at its circumference. should i be worried?
2. I'm confused about the bit above that i've made bold underlined, re adjusting the pivot. That sounds like move the pivot to the outer of its oversized hole (ie away from the hub centre), but I would have thought I should move it to the inner side of its hole (towards the hub's centre) to ensure it can move out later in life when the linings are worn. Or, being less clever, just centre it so the shoes/linings are also most centred. then the whole set-up may spin more true in the lathe.
Any advice on this from anyone? Orabanda?
BTW a pic of test fitting my turnbuckles below. for an experiment i zinc plated them. came out quite well.
thanks!