Kerf
Member
I’m making a new stock for a Vickers Armstrong martini type barreled action and the action screws are giving me a fit. The action screws seem to be threaded ¼”- 26, a non-standard screw pitch. I say, “seems to be” because the screw goes into a thread checker of a ¼”-28 loosely and at ¼”-32 it’s very tight. The major diameter on the threads is .234, while the minor diameter between the threads is .201. Not exactly what you would call a quarter inch bolt. Normally, a quarter inch bolt would measure .245/.222 m/l.
These “action screws” go through a sleeve, not unlike a pillar-bedding sleeve, which is threaded internally and externally. The external threads of the sleeve screw into the wood stock, (like a threaded insert used in knock down furniture), and the internal threads fit the screw itself for a few turns, then the screw slips through and goes on to thread into the barrel action itself. Basically, the internal threads in the sleeve act as a “keeper” so you don’t lose the screws when you loosen them to take the stock off the barrel.
So, my question is: can I convert this over to a ¼”- 28 standard size by simply running that size tap, (as one consort suggested,) or will that just bugger up the situation? I would also have to rethread the sleeve internally and the screw itself. If that isn”t going to work perfectly, I’d rather not muck up the situation, just for the sake of expediency. I’d have to find another more suitable solution, if that’s the case.
One solution I considered was, basically, discarding the British screw and sleeve, drilling new holes in the barrel and action next to the old ones, and making new sleeves. That way, I can drill a hole in the butt of the rifle, and insert the old hardware (screw & sleeve) for the next owner to make their own decision how they choose.
I also considered doing the next owner a favor by using J B Weld to fill the threads on all the parts and re-cutting new threads, thereby using the old hardware with new threads.
Just not sure which is the best solution from a mechanical point of view. And, I’m not certain any of the above solutions would work at all. Any opines you might have would be greatly appreciated.
Thanks, kerf.
These “action screws” go through a sleeve, not unlike a pillar-bedding sleeve, which is threaded internally and externally. The external threads of the sleeve screw into the wood stock, (like a threaded insert used in knock down furniture), and the internal threads fit the screw itself for a few turns, then the screw slips through and goes on to thread into the barrel action itself. Basically, the internal threads in the sleeve act as a “keeper” so you don’t lose the screws when you loosen them to take the stock off the barrel.
So, my question is: can I convert this over to a ¼”- 28 standard size by simply running that size tap, (as one consort suggested,) or will that just bugger up the situation? I would also have to rethread the sleeve internally and the screw itself. If that isn”t going to work perfectly, I’d rather not muck up the situation, just for the sake of expediency. I’d have to find another more suitable solution, if that’s the case.
One solution I considered was, basically, discarding the British screw and sleeve, drilling new holes in the barrel and action next to the old ones, and making new sleeves. That way, I can drill a hole in the butt of the rifle, and insert the old hardware (screw & sleeve) for the next owner to make their own decision how they choose.
I also considered doing the next owner a favor by using J B Weld to fill the threads on all the parts and re-cutting new threads, thereby using the old hardware with new threads.
Just not sure which is the best solution from a mechanical point of view. And, I’m not certain any of the above solutions would work at all. Any opines you might have would be greatly appreciated.
Thanks, kerf.
