Refurbishing vintage brushed motors and ID help?

[El Gecko 1343]

Got some bearings in the mail, so today was all about rebuilding some of my old motors. First went through the old Twisters and Point Blank motors, swapping bushings for bearings, truing commutators, installing new brushes, and general cleanup/restoration and break-in. What a difference, can't wait to run them!

Then I turned my attention to the dark blue unmarked EPIC can. Not sure what's going on with this one? It appears to be a Trinity Speedworks ball bearing endbell (standup brushes) but I have no idea about the armature or can. The armature is smaller overall diameter than a typical Yokomo 27T stock arm, and the wire seems to be larger, although I can't count all the strands to be sure of how many there are. It could be high teens or low 20s.

Anyway the arm fits the can perfect, so I assume it's all a package, but Speedworks motors didn't come with this can as far as I can tell (single mounting holes). The can also has a bushing instead of a bearing, so maybe the endbell was scavenged from a Speedworks motor? I just need to figure out how to secure the endbell properly so it doesn't come loose while running the car.

Anyone recognize that can? Have tips about how to secure the endbell? Who else out there is rebuilding old brushed motors?

[Mad Ax 9312]

I can't help with the motor ID, but strange you should post this because I got out my new (vintage) motor lathe yesterday for the first time since I bought it in the summer and started truing the comm on my old Trinity Revenge of the Monster motor, which saw me through several race seasons with no servicing besides a few brush sets.  I've got a few other brushed motors that refuse to run properly despite brush replacement, so I've got a lot of comm-cutting to do

Good luck getting that old hybrid running again  

[JimmyMcGoose 103]

I have a heap of vintage motors to service but been putting it off! I also need to try and find some of these clips as the ones on the lathe I bought were shot. Any ideas where I might find them? 

[El Gecko 1343]

8 hours ago, Mad Ax said:

I can't help with the motor ID, but strange you should post this because I got out my new (vintage) motor lathe yesterday for the first time since I bought it in the summer and started truing the comm on my old Trinity Revenge of the Monster motor, which saw me through several race seasons with no servicing besides a few brush sets.  I've got a few other brushed motors that refuse to run properly despite brush replacement, so I've got a lot of comm-cutting to do

Good luck getting that old hybrid running again  

Wish I had a lathe! I have been chucking them in the drill mounted in the bench vise and just doing it all by hand and eye

I should have taken a pic but the Point Blank had a really bad hourglass shape that I was somehow able to straighten up. Should do better than it was either way!

[Mad Ax 9312]

17 hours ago, El Gecko said:

Wish I had a lathe! I have been chucking them in the drill mounted in the bench vise and just doing it all by hand and eye

I'd wanted a lathe for a long, long time, and I was fortunate enough to find an old racer selling a vintage one at the Revival back in the summer.  He was even kind enough to give me a demo on how to use it.  My beloved Acto Pink failed during Friday Practice, the comm was in a terrible state having never been serviced since I've owned it, and I got it used back in 2008 or 2009.  So I spent an hour hunched over a chilly table in an open-sided marquee, wearing soggy shorts and sandals while the sun went down and the wind picked up.

Before that I'd been cleaning my comms with fine wet-or-dry, but a lot of my motors have got so bad that the wet-or-dry treatment will see them through maybe a couple of races before they start arcing and cutting out again.  I've got a big stack of motors to service on a cold winter afternoon when the fire's starting to die down and I'm tired after a day of project wrenching.

Definitely worth keeping your eye out for a used one, it's very therapeutic  

[DPR250R 55]

On 11/22/2021 at 11:38 AM, El Gecko said:

Wish I had a lathe! I have been chucking them in the drill mounted in the bench vise and just doing it all by hand and eye

I should have taken a pic but the Point Blank had a really bad hourglass shape that I was somehow able to straighten up. Should do better than it was either way!

How is that drill method working out for you?

 

I have read both sides… from don't ever clean up a comm like that… to you’ll get close to all your power back. 

[El Gecko 1343]

42 minutes ago, DPR250R said:

How is that drill method working out for you?

 

I have read both sides… from don't ever clean up a comm like that… to you’ll get close to all your power back. 

Well so far I've only done the Point Blank and haven't had it in a car yet, but the break-in was very promising (this was the worst--the other motors only needed cleaning and polishing). Seems like torque and top speed are improved, and with bearings instead of bushings it's smoother than ever. Gonna give it a run tomorrow in the Hornet and see what the GPS says.

It was a bit of trial and error, but I've done worse with HO scale slot car motors so I figured why not give it a shot. Just make sure to chuck the comm end of the armature in the drill, otherwise it will bounce a bit at the other end when you try to do anything. I used 400 grit sandpaper to flatten out the hourglass, then finished with a rag I typically use for metal polish (make sure to clean out the slots between comm segments from any polish residue). And then obviously a clean rag to get everything shiny.

I was very gentle with the sandpaper when I started, like a second or two very lightly until I got the feel for how much material it was removing. Wear goggles so you can get close up while you're doing it, and have good enough light to see the edge of the comm as it's spinning--that's key so you can make sure to get the comm profile as flat as possible, so it makes more contact with more of the brush surface. As long as you don't remove too much material, it should be fine. I focused the sandpaper on the largest parts of the hourglass so I didn't take too much away from the center.

Oh also--this is important--I actually used the Dremel in the vise, not a drill. The Dremel allows you to set it at a certain speed and use both hands to steady the sandpaper etc. It turns out 540 motor shafts are the same diameter as a Dremel bit! (or close enough)

[El Gecko 1343]

Also on a related note, I GPS tested the Hornet's Yokomo motor today after its rebuild and it showed a 3mph increase in top speed!

I guess it helps if the motor magnets are glued into the can among other things...

[El Gecko 1343]

Update on the Point Blank: it appears that it's restored to nearly full working order!

Significantly more torque and 1mph better top speed than the Hornet's usual Yokomo motor

Both are 27T stock motors but the PB has MUCH stronger magnets and a better armature, so this is the result I was hoping for!

However on the comm truing front I think it would benefit from a lighter/smaller grit sandpaper like 800 or 1200 before polishing. It took a solid 30 minutes of break-in running at 4.8V to get it smooth and happy.