Post by rbturner on Dec 15, 2019 17:33:03 GMT -5
Here is how I do it.
This is the cracked gear from a Bachmann something or other. The knife is in the picture to help the camera focus.
Measure the shaft.
Next I press the crack together to see if will lay back together well and make the part a candidate for repair.
Select a bit that is a couple thousandths over. This allows for no outward pressure on the repair. In this case the bit in my Harbor Freight set that was best was marked #44. But I always measure with the micrometer because the HF bits are not always the size my Starrett chart shows them to be.
Once reamed out, I generally simply slip the shaft or axle in and add a small amount of super glue. In this case I am not sure where the gear should be positioned on the shaft so I just left it out.
I add a bit of glue then quickly squeeze it together and put the clothes pin back on. I also add a bit of accelerator to glue to speed up the process.
I always run the bit back through the hole while still clamped to remove any glue that sneaked in the hole.
Next I take a mating gear and test how well the repair will work. Many times it will mesh perfectly and you're done.
If you have trouble or there seems to be a 'bump' as you roll past the repair I do the following;
Sometimes the repair leaves the two teeth; one on either side of the repair a tiny bit wider than they should be. As the mating gear comes around the teeth on it will hit the tops of the repair teeth. Scraping or filing the very tops of the 2 crack teeth down a bit will allow the mating gear to contact the repair gear further down the tooth and this will stop the clicking and clunking.
