Attaching NWSL gearbox to frame?
#1
I am making using a small NWSL gearbox to power an HOn3 steamer.  Does the gearbox need to be attached to the frame in any way, or can it jut "float"?  The reason I ask is that the gearbox has no places to attach it - anywhere, and no place where you can drill the housing for an attachment screw.
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Kevin
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#2
In most cases, the gearbox can simply "float", as the driven gear (on the loco's axle) , can't really go anywhere, other than, perhaps, up and down if there's soft-enough springing in the loco.


However, depending on how the wormshaft is coupled to the motor, you may wish to add a connection between the motor's mounting position (or the motor itself) and the gearbox.

This is sometimes necessary when the motor shaft's coupling to the wormshaft is flexible, either as pliable plastic tubing or as universal joints.  In some instances, the motor's torque can cause the gearbox to partially rotate with the axle it's driving - this may cause a u-joint to separate or lock-up due to misalignment of its components.  With flexible tubing as a coupling, there may be a chance of it deforming, which usually has the effect of shortening its reach, thereby drawing the gearbox towards the motor and out of optimal alignment.

The usual cure is to make an "arm" out of sheet brass or similar material, and fasten one end to either the motor (most have threaded holes in the front of the motor's casing) or the motor's mount.  The other end of the arm would be screwed to gearbox, using one of the screws which holds the top of the gearbox together.


If the worm is mounted directly on the motor shaft, though, there's no need at all for such precautions, provided, of course, that the motor is well-secured.

If the latter situation matches yours, you should be fine without any other work, but otherwise, run the locomotive without the superstructure in place and watch to see if the gearbox starts flopping around - test it at various speeds and in both directions - if the gearbox is either drawn towards or deflected away from the motor, a solid connection between motor and gearbox will be beneficial.

I wish that I could offer a photo, but I don't think I have any locos so-equipped nowadays.

Wayne
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#3
Thanks Wayne, good advice. There will be a flexible coupling, probably plastic tubing, but it will only be long enough to join the two shafts. I will try it out without another connection and see how it goes.
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Kevin
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