Broken Gooseneck

[burningwizard]

The gooseneck casting has broken off the forward end of my boom. It looks like it was held in place with 3 rivets. I think I'll need to drill out the old rivets and re-rivet? What kind of rivets should I use? The holes do not go all the way thru the casting.

[GreenLake]

Aluminum rivets. You definitely don't want to work with dissimilar metals.

In operation the forces on the boom will pull it forward, into the gooseneck. That argues for not needing to be too particular about the rivet type.

I can't think of a reason why you wouldn't be able to drill deeper holes (unless anything protruding on the inside would be in the way).

There are sites and stores that supply specialist fasteners. There may be a rivet type that works better in the geometry that you have. But you would need to fully clean out the old rivets to know what that is.

[burningwizard]

Update on how I fixed this:

I drilled out the 3 rivets, starting with a 1/8" metal bit and working up to 3/16", at which point the rivets sort of twisted themselves out onto the drill bit.

Then I tapped the rivet holes for 1/4"-20 machine screws. I believe that if you started with a blank casting (like D&R sells), #10 screws would be plenty beefy, but since the rivet holes left 3/16" holes I needed a slightly larger tap.
After tapping, I gooped the holes and screws heavily with Tel-Gel and screwed them in place.


Everything feels secure and fits back together properly. Hopefully it'll hold for another 50 years.

[GreenLake]

That looks like a creditable repair.

Because the fitting is a solid block, tapping it works very well, of course. The Tef-Gel should mitigate the disadvantage of working with SS and aluminum that would otherwise be in contact.

Nice job and great pictures.