Yes , what I need is a hollow threaded rod with the thread on the outside, looking like this, only sized and threaded as M12-8 threads per cm bolt. I’d have thought there would a vendor for such a thing, but apparently not.
No worries, 1/4 inch standard iron pipe has an OD around 0.53 inch, so I can always drill out the existing threads and re-tap them as 1/4 inch iron pipe threads. Taps for standard iron pipe are cheap and easily available. And the hollow threaded rod for matching 1/4 inch iron pipe is easily found too.
I appreciate the interest of your expert mechanical folks here to find a different method, but for this question I’m only interested if that part is available is all. Like I say, there’s a simple alternative. There’s a second alternative, obtaining an M12-8 bolt and drilling the center out to make it hollow, then cutting off the bolt head. No threads to cut, but overall seems more complicated.
You would have to be pretty precise to drill out an 8 inch bolt.
You’d get 7 inches down and the drill bit would come out the side of the bolt.
Besides finding that long a drill bit would be harder.
I thought that an M12 needed closer to a 7/16 shaft to get decent threads.
So the 0.53 pipe would be too much and you would never get it started.
But then I have no reference material right here, so I could be wrong.
Do the threads have to go all the way from one end to the other?
If you only need an inch of threads on each end; You could chuck up a piece of 1/4 inch pipe in a drill press and take one end down to the 7/16ths with a file while the drill press turns it (like a lathe). Then flip the piece around and do the other end.
I’ve done this before and it works but is time consuming.
1/4 pipe would still have enough meat left after taking it down to 7/16.
Naw…you dont want to get into drilling out a threaded bolt… Unless you have a nice lathe? The lathe is about the only thing that can keep everything lined up perfectly while drilling it out.
