Making the action retention screw for the Brazilian Comblain Carbine

Well it was back to the lathe today for an attempt at recreating the tiny locking screw that retains one of the main action screws in place. This is a very difficult screw to make as the specific thread does not exist in modern-day standards along with only around 1-1.5mm of threading length.

The missing screw that retains one of the key main action screws.

I was able to find a very similar all-thread stock after using some various screws to see what may work. The thread I’m using is 1/8″ x 40 BSW however I have noticed that the original screw seems to have had a deeper cut thread. The first thing I did was turned a screw head blank from some 4140 round bar I had lying around and then countersunk the back.

Steel disc silver soldered to the all thread.

Once the screw head blank had been prepared, I then used silver solder to attach the all-thread onto the blank. I still need to clean it up and then cut the slot for the screw head to finalise. It’s probably not the ideal method for making a screw but options such as fully turning from a lathe and/or using a die is not really an option due to its very small size and my available equipment. I’ll update again once the screw is finished.