I just ordered a pile of Kato 927010 brush, cap and spring set, but I'm sure I'll be launching a few springs into the black hole of my shop, at least until I get used to using a large freezer bag to encapsulate my hands and the parts. I'm thinking of using MTL coupler springs, either Z or N scale as substitute. I'm thinking if the wire material and gauge and tensions are similar, why not? If anyone knows the gauges of MTL coupler springs, especially Z, that would be great. I couldn't find it on their site. I might just have to buy a bunch of sets and keep them as spares for other stuff. EDIT - I just checked out an N scale coupler spring for MTL 1015. It is about .045" dia with about .005" wire size (36 AWG). Not sure if that can carry the current of a motor. When I get the Kato brushes I'll check one of the springs.
Let me know your findings as one of my F7 motors just crapped out on me. I suspect something with one of these components is to blame....
Brush springs may be heat-treated to withstand the higher temperatures of their usage but, if the dimensions of substitutes can be matched, there's no harm in trying them. Too low pressure will cause lower motor speed and too high pressure will also cause reduced speed but higher current draw. Doug
Have you tried some 91% or 99% isopropyl alcohol dropped onto the commutator, spin motor by hand, let it dry and put power to it?
I'd like to find a source for a long piece of compression spring of the same type that I can just cut a short piece off. If that's not an option, I have an interest in winding my own on the lathe using the screw feed, or, more practical,..hand winding around a small screw of the same diameter and pitch of the spring. I don't have practical way to measure the compression strength of one of these
