Looking for dual thread bolt with different sized ends

Never seen anything like that. Does the maximum diameter have to be that of the larger thread? If the size difference is large enough, then drill out the larger one using a lathe, tap to the smaller size, and fit studding.

If the size difference is small, turn down a bolt or length of larger studding and put a thread on that with a die.

I came up with a better idea. I have a drain rod similar to this. Specifically the spiral sharp thing:

It would help to know the application.

Ah, that's what I was looking for, but I thought of another way anyway. I have a drain rod similar to this. Specifically the spiral sharp thing:

The same seller does them in various metric sizes.

You can also make things on a thread cutting lathe.

To be able to use the shop in University, we had to take a short course on using all the machines. This item is a part of a larger project, and thread cutting is involved for this part.

Any machine shop worth its salt, should have a thread cutter.

There's more to cutting threads than what little I learned, but at least I had fun. And the item I made, still works.

The thread in this case, is done with a bladed cutting tool. And it takes multiple passes, to make the thread. Your thread isn't ready after just one pass.

Paul

ROFL! This question was just removed from Quora for "disobeying policies" - didn't tell me which one. I'm guessing a link to an Ebay listing to explain what I'm after is called advertising?

Pre-war Harley 2 stud 3 speed trannies used a stepped mounting stud . Got a '39 and a '40 out case in the shed for a rebuild project . Not enough of the original bike left to call it a restoration .