This last weekend I did a small Mod to my Abrams to fix an inaccuracy in the Heng Long drive sprocket molds. I actually did the fix on a set of Heng Long metal drive sprockets. The modification involved drilling the metal and filling some holes with epoxy, then sanding and filing the metal to cleanup the surface. The result is not perfect, I compromised on a couple things, but is closer to the real thing by a long shot than the stock Heng Long molds.
Step 1. I layout and drill four holes in the hub part. I step drilled them, starting with a 1/16 inch bit and finishing with a ¼ inch bit. This was to ensure my drill bit did not drift off the mark when I started each hole. I also placed a small block of wood inside the hub while drilling to catch the bit when it broke through to prevent scaring the inside. I only drilled the outside half, the part that shows.
Step 2. I sanded the face of the sprocket enough to remove the paint. I also scratched the paint out of the incorrect recessed bolt holes with a hobby knife.
Step 3. I used 5 min. epoxy to fill the recessed bolt holes.
Step 4. I sanded the face flat to remove excess epoxy. I used a file to clean up the drilled holes in the hub, then painted them NATO Green.
Step 5. Use a 1/16 inch drill bit to show the threaded holes in the sprocket like the real ones have. (I haven’t done this step yet)
Note, Abrams tanks use two types of sprockets, I think both interchangeable, that are bolted from the inside of the sprocket, not the outside like Heng Long shows. One type is round on the inside, like Heng Long’s, and one type is wavy like the picture above.