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While trying to re-motor a car with a driveshaft last night, I managed to destroy the coupling spring. It's good and mangled! So, not having an adequate replacement handy, I panicked and reached for the only material within reach that I thought might fit the bill: shrink tubing. I set up the "helping hands" to hold the motor and shaft in place, then heated the tubing until it was nice and snug. It appeared to work splendidly. I popped the assembly back in the care, tested with a battery, and the rear wheels spun. I then tried to sand the tires, and the rear wheels stopped. That should have been a red flag, but undaunted, I carried the car to my track and let it fly. It made a good couple of laps, but just as the smile began to form on my mouth, it stopped moving, the motor still whirring away. The shrink tubing apparently did not couple the shaft to the motor after all.

When it comes to securing drive shafts, I've seen many different flavors used. Some folks use ink tubes from pens, others use specialized tubing that holds firm enough. My problem is that I only have access to what is at my local hardware and Radio Shack stores. Which leads me to a couple of questions:

What do you use as a drive shaft coupler when you replace a motor, and where did you get it? Also, was it a tight enough fit to just slide the new thing on, or did you glue it in place?

Has anyone ever successfully removed and reused the original spring? I had to destroy it to remove it, so perhaps some "how to remove a drive shaft spring" tips would be helpful. I used pliers in each hand, one on the motor, the other on the shaft, and yanked.

Thanks!

Goose, I think I have your address.

I will send you some of my silicone tubing that will work. Enough to last you quite awhile.

Harry

The reason why we have not really covered how to remove them a lot?

Because 9 out of 10 times they were never right to begin with. I have removed a lot of them and maybe a couple have looked ok.

This is why we change them so much because they all seem to be slightly bent, and cause excess pressure.

But you are right, I have some article I did a long time ago...I will dig it out and maybe repost it.

A BIC pen, surely you have a store that sells them?

The trick to removing the spring (and reinstalling a spring) is to give the spring a twist in the correct direction. If you hold both ends of the spring and twist in one direction, the coils tighten up. If you twist the other direction, they loosen. With the motor and driveshaft out of the car, hold the whole assembly in a line and give it a slight twist, and pull gently apart. If things start to loosen, you're going the right direction, and you'll easily separate the pieces. You do the same thing to reassemble, but push the pieces together while the coils are loose.

Not a problem, GN. Let us know how you get along with the spring. :)

Mark's suggestion with the BIC tubing works much better than the spring, but it's handy to know how to work with the spring, too. :banana-rock:

I have used, tubing - from memory either from Pen or I think the stuff used for RC car aerials is the right size, I have also tried lolly pop tubes but the most success I have is with 2mm inner diameter brass tubing. I cut to size, glue on and put a bit of heat shrink over it. Works well and is smoother than the spring.

DM

Check you mail in a couple days. Envelope on the way.

Thanks very much, Harry!

RMinAustralia- I've seen those, and I think they would would great in some applications. What I've presently dealing with is a Carrera Aston Martin DB3, where the driveshaft rests on a small plastic cradle. There would not be room enough for that particular coupler, (at least without dremelling the chassis) although I do have several other cars (particularly Fly's) in which I could see that being a great solution.

And it looks like there will be a 'front-motor proxy', so it might be time for some folks to try this solution. :)

With the grub screws on the same side of the coupler doesn't it throw the balance out of whack? For such a small and lightweight piece I would think the weight of the grub screw would be a problem. Seems like it would be much better if the screws were on opposing sides.

Looks like a great idea for converting static models to slots and leaving interiors intact. What does shfting weight from mid section to front do to a slot in terms of handling?