Mac Side Plates Issues

[kudos]

I've been running Mac motors for years quite happily with the only issue being replacing a clutch on one motor after a few thousand miles.

However, recently the side plates having been coming loose due the screws holding them on, either snapping off the screw heads or just falling out.

I've tried everything I can think of, replacing the screws, using thread locker etc but they just keep coming out.

I even tapped out the 4mm to 5mm and used new screws on one motor but still they came loose.

I then swapped out to a spare motor I had and the same thing happened again, only this time it's on the brake side of the motor, where as on the first, it was the drive side.

It's really odd as this hasn't happened for 1000's of miles then two motors do the same thing at the same time....

Any ideas how to keep the side plates on?

 

[amberwolf]

The only motor (Crystalyte H3548, IIRC) I ever had this problem on turned out to have an axle that was "worn" at the bearing, so that there was enough runout where the bearing pressed on the axle to "wiggle" the covers around. I did everything short of welding the covers in place to no avail.

In my case, the problem appears to be electroplating on the axle (instead of bare metal) with a layer of copper and then a layer of something else, and that was softer than the axle or the bearing race's ID, so it wore away or compressed / deformed, and caused the problem. It's worse on one side than the other, but happened on both sides.

If this is what's wrong, there's no solution besides replacing the axle that I know of.

If the bearings themselves are worn enough to cause it instead, then you can just replace those with quality replacements, and it will fix the problem.

So, check your axle for any kind of "impression" where the sidecover bearings sit. I was going to link a pic of it but appears any pics I had of that axle problem in my thread(s) have disappeared off the ES server.

 

[kudos]

Interesting amberwolf.

Seeing at this is happening with two separate motors it can't be the axle, but I will bear your info in mind for the future.

I'd like to weld up the side plates to be honest, I checked with a magnet and they are not ferrous, I'm not sure what metal is used in the Mac motor?

I have a friend who is an expert welder so I'll see if I can get them fused.

 

[amberwolf]

Seeing at this is happening with two separate motors it can't be the axle, but I will bear your info in mind for the future.

It could still be the axles; it's just not likely that two of them would wear out the same way, unless they both have similar mileage on them.

I'd like to weld up the side plates to be honest, I checked with a magnet and they are not ferrous, I'm not sure what metal is used in the Mac motor?

I have a friend who is an expert welder so I'll see if I can get them fused.

You probably cannot fully weld them on; the heat will probably damage the motor (especially plastic gears, grease, lubrication, etc) inside the casing, and/or the bearings. But you might get them "tacked" on at several points around the casing/cover joint.

However, you can then no longer open them for servicing without cutting the welds.

The covers and casing of most hubmotors is aluminum alloy; which specific one probably varies from model to model / maker to maker, and I don't know how to tell which it is.

Occasionally I see a motor casing / spoke flange made of steel, but the covers have always been aluminum so far for all the ones I've run across. (some have steel cores for the thread-on freewheel section, but the rest of the cover was still aluminum).