I got these two wheel chair motors for a large scale tank-like application. the two motors are Invacare wheelchair motors or merits dynamic wheelchair motors. The two are practically the exact same. Part no. WMT90423 (Model M6).

Now, my question is: can I remove the drive shaft? I know that this is a one-in-a-million shot, but If anyone has any experience with these motors it would be greatly appreciated for your help. I am wanting to remove the drive shaft and replace it with another shaft because the ones that the motors come with are about 2" too short. Another option I suppose is to just weld 2" onto it, but I don't know how much stress that would withstand. So, if you have any suggestions with this, your knowledge is greatly appreciate. Thanks
Mitch

Mitch:

You'd have to open up the gear-case and see how the shaft is attached to the gear inside.

If its just a setscrew, you've got a very easy fix. Just make sure to lock-tite it when you replace it on the new shaft.

If its pressed in, not so easy, but do-able at a machine shop for a few bucks (or perhaps a HS or college class-shop for nada)

If its pinned... well, you have to put a pin-drive on the new shaft too, meaning drilling the steel rod.

Got any way to show the scale of those beasts?

WhiteWolf

I don't suppose adding a section driveshaft with a coupler is an option? If you could find a steel rod and cut it to length, you could couple the two sections together with a steel tube and put a screw on each side of the junction..............maybe.

You could do what I do to extend Subaru steering shafts for lift kits. Get some more stock that is the same size as the shaft, then find a piece of tubing stock that fits over them snugly and weld the tubing at both ends. Strong and extended.

Hmm...all very good ideas. I will open it up when I get a chance to see if it is just set screwed in. But, it it's not set screwed in, I think I'll try the coupling idea and weld it at both ends. The only slight hesitation I have is that these two rods are going to be under a lot of stress most of the time. That is why my first option is just to replace the entire shaft. But if I can't, I think that the welding job might do. Wait, no, I can't do the welding, I would be able to screw it in though. Because, I am putting a bearing on the shaft and bolting it to a steel plate, and I wouldn't be able to put it on if I had the coupling. I could however weld the extension on after I mount the bearings and motors onto the rig, but then I would never be able to remove the motors. This project is going to weight upwards of 1,000 lbs, so, I just want it to be as strong as possible. Again, thanks for the suggestions guys, and any more options are welcome.
Thanks
Mitch

in answer to this, the motors are about 16" long each and about 4" diameter at the end. The drive shaft is 5/8" and they weight about 20 lbs a piece. Two huge monsters for this baby.
Thanks
Mitch