Been working more on new magnets. I’ve done a few since my last update, but I’ll just give one tonight.
The conversion is a Mantua MU-1 power truck, used in the metal Shark Nose and Talgo locomotive. A new magnet is practically a requirement to make it run well, since the old magnet is very weak and can barely move a load. The steel truck mounting plate used in the earlier metal Sharks makes the conversion more difficult, but it should be just like an MU-2 power truck for the rest. Due to a smaller amount of room for a larger magnet, I used a stack of four 3/8"x3/8"x1/8" magnets (could’ve used 1/4" thick magnets, but I didn’t see them when I ordered). I suppose if some filing is done, a 1/2" cube could still fit. Because the magnet plates are held in place by a screw alone on these trucks, they should be glued in place with the new magnet.
And there’s why it’s more difficult to replace the magnet in the older Sharks. The magnet is strongly attracted to the steel plate, and even a large amount of weight can’t hold it to the track properly. Now here’s the fix:
I glued a hefty spring to the top of the magnets, and glued a piece of thick paper to the top of the spring for insulation. The spring effectively holds the truck right where it’s supposed to be, and still allows free rotation. More than a quarter pound of lead over the truck helps too (I have an early model with no extra weight cast over the power truck).
And the results are totally worth