Fixing warped locomotive frame

[bigdawgks]

Hi, I recently bought a Bachmann H16-44 that was in new condition, but after I disassembled it to paint the body and prep it for decoder installation I noticed that one half of the frame is slightly warped/deformed. It's not by much but in one spot it's deformed enough to interfere with the worm gear housing, making it not sit inside correctly. I suspect this deformity is also responsible for one of the frame nuts being practically stripped (it appears the factory just tried to brute force the assembly despite the defective frame :/ ). Anyway, seeing as the model is long out of production and Bachmann has no spare frames for sale I was wondering if anyone has any techniques that could be used to reshape the deformed areas without risking further damage/destruction of the frame. Does anyone know if this is feasible without some specialized tools or am I better off trying to search for a second hand replacement?

[robwill84]

Hope it's not zinc rot. Do you see any fine cracks in the casting?

[tehachapifan]

Hope it's not zinc rot. Do you see any fine cracks in the casting?

Agreed. Unfortunately, it sounds like this could indeed be the culprit.

[bigdawgks]

I do not think it is zinc pest. There aren't any cracks and it appears structurally sound (I tried to see if I could bend back some of it with pliers and it didn't budge). It looks more like a manufacturing defect; kind of like it was crushed on one end.

Here it is in profile, showing it bent at the very end.


This image shows where the primary issue is. The circled part is bent and sticking out into the cast recess for the worm gear housing. It's split off from the rest of the frame and should look like it does on the other half as shown:


I already tried to see if I could bend it straight with pliers but it's not soft enough (and I suspect if it were zinc pest it would have just snapped off after trying this).

[SkipGear]

Strip it and put the frame half in a vice, a thin shim on the outside  of the frame and a similar shim on the very end of the bent area, and squeeze, slowly and carefully.

Either that or dremel out the pinched area to match where it should be.

[Steveruger45]

Using a vice with shims  is what I would try too. However after dry fitting to confirm placement of the pressing/shimming configuration, I would then heat up the warped frame half in boiling water for a while and then quickly place it in the vice/shim set up for pressing using suitable gloves tools so you don’t burn yourself.