- small motor "brush" material ? - 5 Updates
| John Sabino <valuablebook@gmail.com>: Feb 03 12:48PM -0800 Vintage College Football program https://www.collectableivy.com/ |
| John Sabino <valuablebook@gmail.com>: Feb 03 12:50PM -0800 On Thursday, May 12, 2016 at 5:36:29 PM UTC-4, MJC wrote: > Weather Strip" made of "specially prepared copper alloys" and carrying a > ten year life time... > Mike. https://www.collectableivy.com/ |
| Mike Coon <gravity@mjcoon.plus.com>: Feb 03 09:31PM In article <fb00fe6c-406e-4a27-ab37-01e2c7757a81n@googlegroups.com>, valuablebook@gmail.com says... > > ten year life time... > > Mike. > https://www.collectableivy.com/ I think that is called a "non sequitur". But thanks for reminding me of what I wrote ~5 years ago, remembering my long-dead father. Mike. |
| liz@poppyrecords.invalid.invalid (Liz Tuddenham): Feb 03 09:49PM > > Not sure if it is the same stuff, but I have some more recent "Atomic > > Weather Strip" made of "specially prepared copper alloys" and carrying a > > ten year life time... I've missed out on the beginning of this thread, but I had a problem with worn phosphor bronze leaf brushes on a small motor many years ago. They had worn right through and the ends had fallen off. I took an ordinary carbon brush from a much larger sized motor and cut a pair of cubes from it. Then I copper plated one side of each cube and soldered it onto the remains of the original brush, which just acted as a mounting spring. The commutator segments had also been cut through, so I flattened some copper wire and made some grossly oversized segments which I fixed in place with epoxy resin. When everything had set hard, I mounted it in the chuck of a small modeller's drill under a microscope and used a jewellers file to shape it back to size. The final trimming was done by driving the shaft from the far end and mounting the commutator end in a temporary bearing to keep it exactly concentric. The motor caried on working for a long time after that and its performance didn't seem to suffer from the extra resistance of the carbon brushes. (We are talking about a very long time ago, when small motors were almost unobtainable and I had no money to spare.) -- ~ Liz Tuddenham ~ (Remove the ".invalid"s and add ".co.uk" to reply) www.poppyrecords.co.uk |
| Mike Coon <gravity@mjcoon.plus.com>: Feb 04 11:38AM In article <1pmtldd.105m2vn1p4x1naN%liz@poppyrecords.invalid.invalid>, liz@poppyrecords.invalid.invalid says... > carbon brushes. > (We are talking about a very long time ago, when small motors were > almost unobtainable and I had no money to spare.) That's a great story; I especially like the successful copper plating! Conversely, in the early 1960s, I was trying to recondition a 9.5mm projector (https://en.wikipedia.org/wiki/9.5_mm_film) and after fixing the mechanics the motor commutator developed a fault. I had access to company (I was an apprentice) supplies and machinery, and was allowed to purchase a short lenth of copper rod 1" diameter. (I don't remember the price but I only needed a few mm length and have 0.565kg left!) I turned a brass central bush, a mandrel to mount it on, and a short copper tube for the commutator. See https://drive.google.com/file/d/15GOegJInJUCxQbS8BduOh73JMqEuaF3t/view? usp=sharing I don't remember how I kept it all concentric while I filled the gap between bush and tube with epoxy. But when I started using a dividing/indexing head to start slicing the copper into the (IIRC) 14 segments, the adhesion failed and th segments fell off; see photo! At which point I'm afraid I gave up on the projector! |
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