Unknown shifter mount

Question

This screw goes thru the frame (downtube) to hold two shimano 7speed (indexed) shifters. Apparently, one of the bolts is screwed and needs to be replaced. Problem is that the guy who owns the bike doesn't know where to search since we do not know the name for this weird mount, nor when it was produced or how to get one of those.

I thought i might find help here? Possibly an idea for how to replace it?

Update: A friend of mine has a lathe and will just make a new bolt.

Answer 1

You can find what you're looking for under names like "downtube shifter lever boss kit".. You should be able to find something at a bike shop (especially one which works on older bikes) or a frame builder.

Another alternative is to use a clamp.