I don't think I've ever done one of these before... I've given them away, and taken parts from them, but I figured now was the time to try something different.
These motors (I think made by Igarashi, but the experts can fill in that blank) have a lot going for them, and some things not so much. For one, the chrome plating on the thin can metal is hard as heck, besides nice and shiny. Drilling holes in the stuff is noticeably more difficult than other typical cans. The endbell is made out of an actual honest to goodness fairly suitable material. Big news is that the magnets are significantly stronger than the Mabuchis, even though they at least "look" like they're made from a similar material. The Mabuchis read around 670-680 on my meter, the Strombeckers measure 820, and that's a big jump, if not quite into "Arco territory."
I stripped the motor, and it was clear it had been rewound, even though it ran a little rough, but pretty well. Kudos to whoever did the job. I then removed the magnets that are held in by a weird sort of round clip. After cleaning everything out, I soldered a bearing into the can after removing the bushing and reaming out the bushing hole. Since a big problem with these (as with the Mabuchis) is the sloppy tolerances/play between the bushings and arm shaft, I then carefully removed the endbell bushing, reamed out that hole, and epoxied a bearing into that end as well. I figure, the old girl oughta get some respect!
Here's a shot of the inside, with the bearing installed and those neat-o magnets. The "ring" pressed into the can makes reinforcing the inside with nuts or whatnot a problem, so I just drilled some extra mounting holes. The two holes in the endbell were there already; I don't know if they're stock or not.
The resulting hole is around .525", nice and tight. So, I wound me up a 65t/30 on a .460" long by .518" (final OD around .515") stack using a Tradeship commutator. Again, the ones I have now all have the "built-in" CW advance, so timing them CCW puts the tabs in a difficult position for winding. I still advanced the timing a bit more than usual here (around 15 degrees CCW), because I have a good relationship with the "armature-winder" and didn't think he'd mind too much.
One of the bad things about these motors is the brush and spring arrangement. You need to be really careful removing the spring retainers, because the springs will go flying into the netherlands where odd socks and other irretrievables go... never to be found again. To make things even worse (!), reinstalling everything is about as finicky as you could possibly imagine. Then, to make things even worserestest, I figured out how to reinstall the springs, brushes and retrainers but discovered that the can screws I installed prevented the retainers from fully seating. See, I drilled the holes as far north as I could so they wouldn't interfere with chassis rails, but that had the end of the very short screws sticking out into the track the retainers ride in. That meant nibbling-away at the retainers so they wouldn't contact the screws, which would have also created a dead short.
So, after all that, I got the assembly done and this is one sweet motor. It's super smooth, and gets up to some impressively high RPM, while drawing relatively little current. 65t/30 is a great wind for the old motors, for this Strombecker with its bearings and strong magnets, it's a humdinger. You won't see many rewound versions of these with bearings on both ends, and with good reason (whew!), but there's plenty of potential in them if you can get past the "issues"!