Shimming gear box on brass locomotive

[tstage]

Greetings,

I have a brass locomotive that has too much axial play at the top of the gear box - i.e. the gear box rocks back 'n forth slightly axially with the drive shaft:

Because of this, the drivers bind slightly.

I'd like to add shims on each side of the gear box axle to minimize the rocking so that the locomotive runs more smoothly.  If I press down on top of the gear tower to keep it from rocking, there is a noticeable difference in smoothness.

Is there a recommended shim (e.g. C-clip) to accomplish this?

Thanks,

Tom

[gmpullman]

Hello, Tom

You might want to consider trying a torque arm that will help keep the top side of the gear case from "twisting" as the power is transmitted to the axle.

See page 26 here:

http://schutzer.net/Brass_Clinics/RebuildingBrass2008a.pdf

Maybe you could cobble something together on a temporary basis to see if it resolves your problem then go on to make a suitable bracket if it does.

Good Luck, Ed

[doctorwayne]

tstage

I'd like to add shims on each side of the gear box axle to minimize the rocking so that the locomotive runs more smoothly.

I fixed a loco for a friend with the same problem...the gearbox was flopping around from side-to-side, but all it took to remedy it was a couple sheets of fairly thick styrene with some thinner sheet styrene cemented to it to create a tight fit within the loco's frame.

The loco runs like a charm.

Wayne

[wrench567]

  Tom.

 A torque arm from the motor mount to the gearbox will keep it from the fore and aft movement and the rocking side to side.

 Also consider a universal kit from NWSL. The tubes have a tendency to creep on the shafts and rub on the motor or gearbox.

    Pete.

[tstage]

gmpullman

Hello, Tom

You might want to consider trying a torque arm that will help keep the top side of the gear case from "twisting" as the power is transmitted to the axle.

See page 26 here:

http://schutzer.net/Brass_Clinics/RebuildingBrass2008a.pdf

Good Luck, Ed

Thanks, Ed, and funny you should mention the above.  I was looking through that very clinic .pdf a few days ago (on another project) and remember seeing the torque arm remedy.  Whoda thunk I might be using it soon after on another project only because I decided to organize my locomotive & rolling stock product boxes that I had stacked in the closet.

The photo on pg. 26 shows the one end of the torqure arm attached to the top of the motor.  I think I'll opt to bend it 90^o at that location and affix it to the front of the motor bracket.  I'd rather do that than risk drilling a hole into the top of the can motor housing.

wrench567

  Tom.

 A torque arm from the motor mount to the gearbox will keep it from the fore and aft movement and the rocking side to side...

    Pete.

Pete,

Thanks for the confirmation and the universal kit suggestion.  The gearbox is solid fore & aft; it's the "roll" that's the issue, as shown below.  Agreed - The torque arm should do the trick. 

Tom

[tstage]

I noticed that the original black tubing was slipping on the motor shaft when the motor stalled so I replaced it with DuBro silicone fuel line, which I've successfully used on a few other locomotive rehabs:

Not only has this eliminated the tubing slippage on the motor shaft, the axial rocking has diminished noticeably, as well - although not completely.  The torque arm will still be needed - especially if I want to get improved slow-speed from the locomotive.

Another thing that I just discovered is that the gearbox rocks considerably less in reverse than it does in forward.

Tom

[Overmod]

Looking at this, you might use JB-Weld or epoxy on the front of the motor and back of the gearbox and make a turnbuckle arrangement with threaded rod to go between them.  This would let you fine-adjust the alignment and then put a little Loctite to hold it there.

[wrench567]

   Hi Tom.

  It may be the angle of the photo but it appears that the motor and gearbox shafts are on a different level. I have found that same situation on 90 percent of my brass too. And when the driver springs compress it will be even greater.

  I have fixed this several ways. Slot the holes in the motor mount. Shim under the motor mount. And slant the gearbox rearward and tilt the motor shaft/mount to line up. I also line up the shafts with the springs fully compressed. I always add as much weight to the locomotive so the springs are fully compressed anyway.

    Another way to fix the gearbox wobble side to side is to file the bottom of the housing and maybe a little off the lower cover. Careful not to take too much off. The mesh of the idler gear and axle gear will be too deep.

  I have a brass locomotive where the gear box shell rides on bronze bushings on the axle. Another alternative.

     Pete.

[mvlandsw]

It seems to me that side to side rock would be caused by loose bearings between the gear box and the driver axle. Maybe a worn slot in the bottom of the gearbox if there are no actual bearings.

If you change anything there be careful to maintain the correct gear mesh.

Mark

[snjroy]

wrench567

   Hi Tom.

  It may be the angle of the photo but it appears that the motor and gearbox shafts are on a different level. I have found that same situation on 90 percent of my brass too. And when the driver springs compress it will be even greater.

  I have fixed this several ways. Slot the holes in the motor mount. Shim under the motor mount. And slant the gearbox rearward and tilt the motor shaft/mount to line up. I also line up the shafts with the springs fully compressed. I always add as much weight to the locomotive so the springs are fully compressed anyway.

    Another way to fix the gearbox wobble side to side is to file the bottom of the housing and maybe a little off the lower cover. Careful not to take too much off. The mesh of the idler gear and axle gear will be too deep.

  I have a brass locomotive where the gear box shell rides on bronze bushings on the axle. Another alternative.

     Pete.

 

I agree with Pete. The rubber tubing configuration works well when both shafts are aligned. The rubber is not that flexible and the misalignment will cause some wobbling. In this case, it's an easy fix since the motor shaft is lower than than gear box shaft (Pete explains the fix very well). The opposite situation (higher motor shaft) would have involved a new motor, or the installation of a U-joint. I have many brass locos with the rubber connector and they all work well and smooth.

Simon