This was a feature of the model Armstrong RML cannon that I was not looking forward to. (to which I was not looking forward. Plogies to W Churchill. Something about split infinitives).
It is small, cannot be CNC’d with my degree of knowledge, and requires a lot of stuffing around. Which means filing. Or in my case, use of a Dremel.
This is the result after 5-6 attempts. It will have to do.
Occasionally I have a good idea, try it out, and after it works, I think “I should have taken some photos of that for the blog”.
Today I had one of those moments.
This was the result….
This morning, at the GSMEE Zoom meeting, I asked my fellow members where I could obtain some rivets which I could NUT into position. The reason being that some rivets in my cannon chassis are located in impossibly small cavities. And the dome end of the rivets are visible. Apparently “rivet-bolts” are available, but I could not find a supplier by searching my usual suppliers. One GSMEE member had some spares in BA8, but I suspected that I would need more than his small supply. And I was concerned that the dome head size might not match my copper rivets already installed.
Then I had a brainwave! Why not put a thread on my existing copper rivets! So that is what I tried. And it worked!
The biggest issue is not damaging the copper rivet head while holding it and running a threading die down the shaft. The copper is very soft.
The rivets in the photo above have a shaft diameter of 2mm. And the head is easily damaged.
So I tried this…..
And a 2mm threading tool was required…
Holding the rivet like this does leave a 4mm non threaded length of rivet shaft, but it can be packed with washers, or something else. It works!
So that was my brilliant idea for today. HEY IT WORKS!
Devil’s advocate says snug fit with Loctite? Love those pliers.
The pliers are brilliant. I should do a post on them.
The ratchet has to slide on splines, and its mating gear is free spinning on the shaft, so not much scope for Loctite in this instance. John
You could maybe perhaps submit your ratchet gear needs to Joe Pye and see what he comes up with. May not be for this build but who knows?
Another maybe perhaps, some reader of this blog just might have an old machinist’s trick for threading copper. It sure is sticky stuff as I also have found out trying small diameter threads on copper brake line.
Great to see continuing progress even if not at the speed you would like.
So far I have had 100% success at threading the copper rivets. 2 done. 2 successful! I suspect that the 2mm shaft diameter helps.
Ratchets done. Moved on…. but thanks for the suggestion John.