Sunset 3rd Rail PRR P5a Rubber Driveshafts

I would imagine they had some sort of glue, perhaps rubber cement.

One of the standards of 2 rail O scale is what’s called Toyota 0 vacuum hose….pretty much used by a lot of O scale model makers to connect drivelines……not sure how flexible they have to be on your example…….I’d be coming up with a much better solution,….rubber wouldn’t be on the table. This might be a good job for those handy double jointed constant velocity shafts I’ve borrowed from the RC car industry. ….what’s the OD of both shaft ends in mm??.

Pat

I use silicone fuel tubing from my local RC hobby shop. comes in three different sizes and usually sold by the foot. they use it in RC airplanes for fuel lines.

@harmonyards posted:

….what’s the OD of both shaft ends in mm??.

The shafts all seem to be 3mm.

I think what happened is someone tried to lube the shaft bearings, used to much, and then it ran along the length and caused the rubber to swell… or maybe eat away at whatever glue was there. If there was glue, there’s no sign of it now.

O.D. Of the tubing is ~ 6mm

@rplst8 posted:

The shafts all seem to be 3mm.

I think what happened is someone tried to lube the shaft bearings, used to much, and then it ran along the length and caused the rubber to swell… or maybe eat away at whatever glue was there. If there was glue, there’s no sign of it now.

O.D. Of the tubing is ~ 6mm

The shafts I’m sure you’ve seen me use are available in 3mm ID’s so you’d be in the game there,….if I were a betting man, I’d say they’d work great for anything O54 & larger, ….anything tighter, you might get in trouble with U joint angles,…….I’d be getting away from any kind of hose in a heartbeat, but that’s just me, ….There’s certainly enough slip yoke built into these shafts to do what you want to do,…..

Pat

@harmonyards posted:

One of the standards of 2 rail O scale is what’s called Toyota 0 vacuum hose….pretty much used by a lot of O scale model makers to connect drivelines……not sure how flexible they have to be on your example…….I’d be coming up with a much better solution,….rubber wouldn’t be on the table. This might be a good job for those handy double jointed constant velocity shafts I’ve borrowed from the RC car industry. ….what’s the OD of both shaft ends in mm??.

Pat

Pat

I do not agree with your first sentence. Although there are some 2 rail O scale modelers who regularly recommend this approach, most that I know have the same qualms about rubber as you do.  After all, from a drive perspective the number of rails is irrelevant, but the torque is similar!  U - joints work just fine, don't wear out, and can flex quite a bit.  I generally get mine from NWSL and/or P&D hobby shop. Or even Stock Drive Products

At one time I had the Sunset loco in question.  I cut out the hoses, and installed U joints

But the all time hall of fame  drive system was the Athearn HO Scale Rubber Band diesel drive.  Look it up:  A double shaft motor was coupled with rubber hoses to two 2 1/2" long, 1/16" diameter shafts, each with a single midpoint white metal bearing.  Rubber bands dropped from the shafts down to larger drums on the axles.  This is how they did the speed reduction.  Of course the rubber bands had to twist hrough 90 degrees to change the rotation orientation

I think GM later copied this idea for the fan belt on the Corvair

John

Honestly, I don’t see how a U joint would work. I’d need two between each axle, and can’t see how that would fit.

Remember we’re talking about a P5a electric. Three axles, only about two inches between axles, probably less than an inch between the ends of the shafts.

The axles are rigid longitudinally, but the front and rear are sprung so they can travel vertically. A single U-joint might work, but it might need to be a slip yoke.

@rplst8 posted:

Honestly, I don’t see how a U joint would work. I’d need two between each axle, and can’t see how that would fit.

Remember we’re talking about a P5a electric. Three axles, only about two inches between axles, probably less than an inch between the ends of the shafts.

The axles are rigid longitudinally, but the front and rear are sprung so they can travel vertically. A single U-joint might work, but it might need to be a slip yoke.

I had no idea the gap you’re working within, …..probably hose is gonna be the only solution,…..Try the product Rick mentioned, …..

Pat

Thanks all. I think we have a hobby shop that does the RC car thing. Either that or maybe NAPA, lol.

@rplst8 posted:

Thanks all. I think we have a hobby shop that does the RC car thing. Either that or maybe NAPA, lol.

Or the Toyota dealership,……😉

Pat

@rplst8 posted:

Honestly, I don’t see how a U joint would work. I’d need two between each axle, and can’t see how that would fit.

Remember we’re talking about a P5a electric. Three axles, only about two inches between axles, probably less than an inch between the ends of the shafts.

The axles are rigid longitudinally, but the front and rear are sprung so they can travel vertically. A single U-joint might work, but it might need to be a slip yoke.

Take a look at the NWSL U joints. They have double balls, slip joints and wide angular range you need

https://nwsl.com/collections/s...driveline-universals

You can shorten the cups, or round the ends if you need to:

@John Sethian posted:

Take a look at the NWSL U joints. They have double balls, slip joints and wide angular range you need

Are they plastic?

@rplst8 posted:

Are they plastic?

Yep

Pat