[Tuske427]

Over the weekend I took on the challenge of repairing 2- early Formula wheel hubs that belong to @65madgoat. These are the ones with the straight cut groove inside and corresponding part numbers.

The first one had what I was told a broken bolt inside. No. It was a broken tap that was crooked and really boogered up the screw hole. As you can imagine, a tap is hardened metal whereas the hub itself is a cast aluminum alloy. Neither my drill bits or end mill bits had a chance. Fortunately I had some dremel/ roto zip grinding bits which did the trick. I was able to grind enough of it away (I used my mill for precise grinding) to break it into smaller parts to extract out. Near the end I broke the bit, but it's replaceable.

From this I cleaned the surface up for easier working.

[Tuske427]

Next I bored the hole out straight to be sure it was free of any tap remains as well as having a good fresh surface to bond with my aluminum brazing material. I then proceeded to heat up the hub with my propane torch to get it to the specified 725-800 degree temp needed to melt the brazing rod and filled up the hole.

After it cooled I resurfaced it on a lathe, drilled & tapped a new 10-24 screw hole and now this one is ready to be repainted and reused again

[Tuske427]

For the second one- this one had been dropped at one point in its life and a chunk broke off. To fix this one I needed to make a basic mold of the exterior surface to contain the molten aluminum brazing rod. I did this by shaping some 20 gauge sheet metal and used a hose clamp to hold it on while filling the area up.

Note: my first pass at this the mold was too close and the material didn't fully flow through far enough to the exterior so I did it again by adjusting the mold to sit away from the part slightly to let the molten brazing rod flow further out.

[Tuske427]

Here are pics of what it looked like with molten material inside, the results of my first attempt, and then the second attempt. You'll see there is some material shortage with that first attempt requiring another pass at it.

[Tuske427]

After the second attempt I ground down some of the bulk on the exterior and then put it back on my lathe to resurface it. The final results are pretty good, though there are two very tiny gaps at each end. These should be small enough to either spot putty/ epoxy or perhaps just paint and use it. It's certainly better than it was before and is usable once again.

John- you're on your own for painting the proper wrinkle finish on these, ha ha

[VCho455]

Nice work!

[4dblnkldude]

Damn! Pretty crafty, I probably would have thrown them away.

[Formulabruce]

Nice work Tuske! I have a 69 that needs a broken drill bit removed, etc.
How far did you turn the outside down? I didn't measure them when I had them here.
Up for another challenge? .. Bruce

[rwfisher]

Well done!

[Tuske427]

Originally Posted by Formulabruce

Nice work Tuske! I have a 69 that needs a broken drill bit removed, etc.
How far did you turn the outside down? I didn't measure them when I had them here.
Up for another challenge? .. Bruce

I only turned the outside just enough to clean up the area I repaired. there's a slight curved surface to the hub and I didn't want to ruin that. It's still thicker than the later ones, ha ha. Attached is a pic- the one on the left is the one I repaired/ you painted and the one on the right is another hub from a 1977 model.

I'll DM you on the one for repair

[Formulabruce]

Wow, cool pic, shows the difference well.