01-01-2018, 12:47 AM
Quote:
doctorwayne Wrote:gna Wrote:....it seems to have broken axles. Apparently the best fix is to buy a mechanism from Bowser, but they don't make them any more. Any advice?...
It's been a long time since I had one of those Bachmann Northerns, but if I recall correctly, those locomotives have split axles which press onto an inner metal axle. The portion of the plastic which slips over the metal tends to split, which then allows that, and the driver attached to it, to slip out of quarter, stopping the locomotive. I used ca to cement mine in place - it's not a permanent fix, though, as it doesn't adhere well to that type of plastic.
As I said, it's been a long time, but a possible solution might be to encase the mid-portion of those plastic axles in brass tubing. You'd need to ensure, though, that the tubing doesn't touch the frame of the locomotive, which I think is metal. The reason for the split axle set-up is because current pick-up is via the drivers only, so if the tubing touches the frame, it'll likely short things out.
For this repair to be effective, the tubing needs to be a tight fit around the plastic portion of the axle.
I repaired a split axle gear in a Proto USRA 0-8-0 using this method, and had to ream-out (using consecutively-larger drill bits) the tubing until it was a press fit onto the hub of the gear. I used numbered drill bits, which have smaller increments of change between consecutive sizes than do fractional-sized bits.
Wayne
I had some time today to work on locos. Here's what the Northern looks like on the inside:
It looks like all the plastic axles are cracked:
Doesn't look like there's much room for brass tubing--maybe a ring? I also have some special Loc-Tite for plastics I could try. I don't hold out a lot of hope for the repair, though. Poking around the interwebz leads me to believe it's a fairly common problem. A few people looked into 3D printing gears on Shapeway, so I may check that out.
I also worked on my E6, testing it on DC, then Installing a TCS T1 decoder with temporary wiring:
Runs ok, but lots of minor problems--screw backing out, stray metal screw on bench sticking to motor when fixing :oops: Think I've got it now. It needs to run quite a bit more to break it in.
Any guesses what I'm trying to model here?