by Arutha » Mon Jul 18, 2016 12:53 pm
I use mainly Bergeon bushes but dont buy all the sizes, I buy the smallest internal diameter sizes in the 2mm, 2.5mm, 3mm, 3.5mm and 4mm, and all 2mm thick,and then just broach them out to fit the pivot. I did look at a bushing machine but could not justify the price.
I use a pillar drill and all my bushing only drill bits were checked in some scrap brass to make sure they made the correct size hole. They are backed off slightly so they dont grab in the brass. The only bushes I make tend to be centre arbor bushings as they are quite large, barrel arbor bushings and barrel and cap bushings.
I can get a whole clock bushed pretty quickly now using what I have.
When I bush I check the original hole is not oval, if it is I even out the hole with a small rat tail needle file. I then drill out for the bush and clean up the edges of the hole with a larger drill bit by hand. The bush is then hammered in place but I then turn the plate over and hammer on the front of the bush. This does two things, it rivetts it in place and also work hardens the brass hopefully making the bush last longer.
Oil sinks are cut by hand with old drill bits or ball burrs etc
I broach the hole to fit the pivot and then smooth broach. With practice the whole process becomes very quick. The only time this system will fall down in if your clock plates are thicker than 2mm.
Paul.