Loco Repair - More Slippage

[Cogent]

Hey Everyone,

I found the problem with one of my locomotives... well actually, several problems, but one in particular I am not sure how to remedy. The small hubs on either side of the main motor axle (show in the picture below) slip and so the motor just spins and won't drive the dog-bone axles. How can I get the hubs to not spin on the shaft?

Let me know if my terminology is all wrong.

Thanks again for everyone's help.

 

[Fred_M]

My first choice would be getting new yokes, but that's prob impossible. Clean them real well with alcohol and let them dry (degrease). Put a drop of ca in the yolk and push it on the motor and wait a day. That should do it. FRED

 

[Graham Hoffman]

NorthWest Short Line makes high quality driveline coupler sets (eg, no. 482-6 for 2 mm dia. shafts) in sizes to fit virtually any shaft size. They are available thru your LHS thru Walthers. Try these if gluing the cups on doesn't work (be especially careful not to let any CA get to the shaft bearings!).

 

[shaygetz]

Fred's fix will do it if the universal is not made of Delrin, a slippery plastic used primarliy to make self-lubricating bearings in model trains.

The club uses a Fleishmann turntable. When it stopped working, I pulled it apart to find essentially the same problem you have. Since finding parts was out of the question due to the age of the turntable, I was forced to fix it or lose it to the diesel guys for space to add a--- :cry: --- diesel servicing facility. By flattening the shaft slightly with a pair of side cutters, I was able to slip the universals back onto the shaft. The knicks caused by the plyers plus the slightly out of round shaft keep the socket in place. This fixed the problem well enough that its lasted a year so far.

 

[shaygetz]

Let me know if my terminology is all wrong.

Thanks again for everyone's help.

BTW...

The armature's connected to the motor's shaft...

the motor's shaft's connected to the socket...

the socket's connected to the ball joint...

the ball joint's connected to the drive shaft...

....and that's what we call a universal drive assembly!

I think I'll go to bed now ops:

 

[Cogent]

Aha! So the proper terminology is that the socket is slipping on the shaft. :-D

I was wondering if I simply "keyed" the shaft if the socket would stop spinning enough for the motor to drive the wheels. I think I will try that before using CA because I just know I would end up gluing the motor bearings.

Thanks. I'll let you all know how it works out.

 

[jon-monon]

use gel super glue, put it on the hole, none outside the hole, then press it on the shaft. That should push the glue away from the motor.

~or~

Peen the hole. Sounds sick, but it's a simple process. Use a center punch, prob. get by with a nail assuming it's a soft material. Go aroundthe hole and make an indetation as close to the hole as you can. This will make the hole smaller and it will be a press fit again. Be carefull if it's pot metal, might crack :O I usually do 8 indentations. Tap gently. A little goes a long ways.

 

[Medicine Man]

A little dap of J-B weld in the hole is worth a try as well

MM

 

[Woodie]

Peen the hole. Sounds sick, but it's a simple process. Use a center punch, prob. get by with a nail assuming it's a soft material. Go aroundthe hole and make an indetation as close to the hole as you can. This will make the hole smaller and it will be a press fit again. Be carefull if it's pot metal, might crack :O I usually do 8 indentations. Tap gently. A little goes a long ways.

Vote 1. Jon-monon for Chief Brain Surgeon.

 

[petey]

Good advice. NWSL probably has the motor shaft coupling, but what size shaft opening, and even more difficult, removing the coupling from the shaft, and reapplying it. My problem would apply to a Balboa PA, w/Jap motor. What has happened is that, one of the tongues on this Delrin coupler has broken off, these tongues mate with two tongues on the connecting, ball-bearing coupler that carries the first keyed, shaft. I don't believe I can could get my gear puller between motor bearing, and back side of the broken coupler, to pull off. I don't know how to drive the replacement coupler, squarely back on the motor shaft. Will NWSL do the removing & replacement? It's nice to have a replacement source, but it's frustrating not to be able to change the parts out. I have also thought of drilling the broken coupler, at the point of the broken tongue, and inserting, say two pins that would then act as the missing tongue. Also, what of sleeving the broken coupler, so that the sleeve would cover both the broken coupler & a small length of the mating universal, but there is very little clearance between the broken coupler diameter, and the motor mounting plate. It would have to be very thin walled.

 

[shaygetz]

Petey, on my Cab-forward, I had to lengthen the drive shaft between the two gear towers. I just don't have the coin to get Hobbytown or NWSL stuff all the time. What I did do was to cut the shaft and extended it the desired length using heat shrink tubing found at most hardware stores. The thin walls cleared everything and it's held up like a champ thru some pretty impressive loads. Just be careful with the flame needed to shink the tubing ops:

 

[petey]

Hi Shaygetz,
I had to edit my first comment. There seemed to be a distinct disconnect between what's left of my brain, and fingers.
OK, so is this what you are proposing, sleeve the broken motor coupler, and a part of the first ballbearing coupler, thereby partially fusing the two, at their mating ends? This would somewhat restrict the BB coupler's movement, but movement might then be accommodated by the slight movement in the keyed shaft, and at the BB coupler at the tower.
What device do you suggest for shrinking?
By the way, this engine will weigh 24+ ounces, when I add the last weight, so there could be quite a bit of torque involved.

 

[shaygetz]

Here is a pic of the drive shaft. You can see in the center where the shrink wrap is on the shaft. I think what helps it in this instance is the oval shape of the shaft and that the shaft is plastic. The loco weighs in at 21 ounces and regularly pulls 17-21 fully weighted cars. At full throttle it only bounces slightly in the center. The fix is three months old so time will tell whether it holds up.

 

[shaygetz]

On another locomotive, I copied a simple universal socket extension using K&S 1/8" and 1/16" telescoping bar stock and straight pins. Made with only a file and a pin vise, it's less than 1 1/4" long and quite a brute.

 

[Cjcrescent]

Shay;
How close to P'cola do you live? If close go to Bobe's Hobby House and get a piece of the smallest silicone fuel tubing for an airplane he sells. Reinforce your joint with this as the shrink tubing repair will eventually break probably sooner than later. If you have room around the shaft, and I'm not too sure of this,(I haven't had to repair a Rivarossi in ages,) go to Home depot, Home Quarters or Lowes and get you some neoprene tubing in the form of Aluminum window screen spline material. It comes in three sizes, may need to get some of each size, is round and is like 4.50 for 50ft. (You'll never use it all.)

I've been using this stuff, neoprene and silicone tubing, for years to repair all kinds of connections in steamers and diesels from old varneys to modern Overlands. Makes the mech a whole lot quieter as well. I've had problems with Hobbytown type universals eventually stripping on the shaft and since they appear to be delrin, not much works to glue them.

 

[hd8091]

the tubing repair works wonders..I've used it several times, I'd also recommend your local NAPA store they have vacum tubing in all sizes and you ccan buy it by the foot,it's cheap .like me

 

[jim currie]

try red locktight but dont plan on removing

 

[Ray Marinaccio]

Jim,
I know what you mean about the Loc-tite.
I had a Montesa motorcycle that kept sheering the key on the flywheel. I put in a new key with some Loc-Tite stud and bearing mount on it and it never came off again. No matter how hard I tried.

 

[petey]

Slipping

Here's some additional help in stopping the slippage. Knurl the shaft, that is, cause the shaft to assume indentations; "teeth", thereby upsetting its smooth surface. You can do this, thusly, use a pliers with sharp serrations; squeeze the shaft, so that the teeth marks run parallel with the shaft (you want to stop radial movement of the coupler). You must not bend the shaft, however, in applying pressure to it. If you're concerned about this, use a file, either triangular or flat (as long as you can get a toothed edge against the shaft). Turn the file at an angle, and move it back and forth, until you have a SHALLOW groove in the shaft. Do this again, at another point on the shaft, NOT directly across from the first groove(you don't want to weaken the shaft).
Then try to slide the coupler on the shaft. You will have to hold the shaft in place while doing, so that you are not applying undue rearward pressure. If it will not go on fairly easily, smooth the shaft somewhat with your file or sandpaper (ACTUALLY YOU CAN PROBABLY DO THE SERRATING WITH A MEDIUM SANDPAPER TO BEGIN WITH).
If your coupler is metal, a small drop of super glue should work; if plastic, I would try two part epoxy, or silicone glue.
This takes longer to write, than to perform.

 

[Allstate81140]

Hi Steve and all. Steve, Super Glue or it's equivelent will work, but watch it. After applying the glue on the hub, keep end of motor shaft tilted to floor so glue doesn't get into bearings.

When the guys told you it could get in the bearings, believe them. I have a tape player (very expensive) that the belt pulley came loose on. Glued it, and presto, never came off. However, the motor doesn't turn either. Ha ha. I am going to have to try Goof off or something, and pray that those aren't plastic bearings in that motor. Nothing to lose now. Ha ha. Can't get parts anymore, but is a very high end unit.

Other thing you could try, depending on the actual size of those hubs--take them to a machine shop and see if they could tap and put some allens or straight slots in there. Don't you guys dare laugh. Ha ha. Just another brainstorm.

Bye all. Jack.