Tues 1-23-18 12:31 a.m.
Athearn axles have a tendency to crack, the wheels loosen in axle tubes, and the locomotive can fail to run properly. The root cause of the failure is that Delrin (axle material) is not annealed. Over time, the Delrin shrinks and cracks with age (or so I am told). Of course, the axle tubes can be replaced. However, I like to repair the existing cracked axles. There are a variety of ways in which this can be accomplished. For all methods, I use an NMRA gauge to check the flange-to-flange distance. 1) Per a U-Tube presentation about repairing a Bachmann locomotive, shrink tubing can be applied over the cracked axle. 2) I have tried using a soldering iron and making plastic fusion welds or building up the cracked axle with additonal Delrin stock. I have experienced mixed results. Sometimes the crack reappears. 3) A tight-fitting washer (or tube or bushing) can be applied over the axle. I have made washers from aluminum and tin can lids. The washer can be attached with cyano-acrylate adhesive (Super Glue). 4) each end of the axle tube and wheel nub can be drilled and pinned using a small drill bit and a section of discarded paper staple or straight pin. 5) Today I found that the axle tube can be wrapped with sewing thread and mopped with Super Glue. I generally start by squeezing the cracked tube togehter with needle nose pliers. Then I provide a shallow plastic fusion weld over the crack. Then I wrap the cracked axle tube with thread and mop the surface with Super Glue. (Note: It helps to take a small dab of glue and put it on the end of a tiny screwdriver. Then the dab of glue an be used to attach the end of the thread to the axle tube. Then wind the thread on the axle tube and mop the thread with Super Glue.) Next, I use a jeweler's rate tail file or a drill bit to open up the axle tube bore. I may use Super Glue or Threadlocker 271 (Red) to hold the axle tube to the wheel nub. This work must be done quickly and an NMRA gauge used to check flange-to-flange distance as the adhesive sets up in the parts.
Now here are some exercises for the reader. Similar repairs can be made on cracked drive shafts for Athearn diesels. There are a variety of inexpensive diesels where the gears crack. The gears consist of a boss or hub on one side, then the gear, and a boss on the other side. I start by pusing the cracked gear togehter with needl nose pliers and make a careful palstic fusion weld. (Note: I have a soldering gun where I used a piece of discarded Romex copper wiring to make a heating element. I flattened the end of the heating element on my bench vise. The tip allows to cutting, melting and welding of plastic.) Where the cylindrical boss meets the side of the gear, there is enough space to provide a few wraps of thread around the boss. Again, I start by gluing the end of the thread on the boss. Then I carefully wrap and glue, wrap and glue the thread a bit at a time (that is, small amounts of glue on a tiny screwdriver). I thrim the excess thread off with a single-edge razor blade. Then I mop the surface of the thread-covered boss with Super Glue. It is not that difficult, but take it slow and easy and do neat work.
I hope this is of some help. Please do not be afraid to fail. My successes were often the result of failures and continued work.
