Saturday, April 19, 2014

Just screwing around: making hard to find replacement screws

I had a guy asking for some replacement stock screws for a Mosin Nagant 91/30 a while ago and having none left in my parts bins I decided it was time to make some.  Not wanting to make them out of the 0-1 I had on hand I secured some 3/8" cold rolled round stock from a good friend who works for one of the big metal suppliers here in town. The general rule with stock screws is that you want the material to be softer than what the receiver is, the idea being the screw is a consumable....the receiver not so much. If the screw was harder than the receiver you might run into some problems.

Anyways on with the screwing around......First determine the rough dimensions by carefully measuring and double checking before cutting, Or if you have a sample already just hold the thing up to the bar stock and mark it with a sharpie....either way works just well for these old war horses.

Classic Sharpie layout
 I used a rounded general turning HSS tool for turning the cold rolled round stock, cold rolled tends to tear easily, its hard to get good cuts on the steel if you're not used to the stuff. I managed to use a rounded general turning tool with slow speeds and feeds with lots of oil and excellent results (I think).
I did not have a square right hand facing tool ground so I was just using a "general turning tool"
 This spring/summer is going to see some changes in the shop, I am finally going to build a proper tool grinding station with a rest. I have been needing one for a long time and its way past due. If you know half of anything about proper lathe tools you'll realize I am making more work out of this than is really needed and not using the carbide tool below correctly. This should be fixed once I get my tool grinding station built.

Backwards way to square up the shoulder of the screw, not proper but it works.
 Using a parting tool we slowly cut the completed screw away from the rest of the round stock. After this we will will take the bolt to a 1/4" (the screw is slightly over 1/4" but it still works) collet and slightly dome the head, radius it and prepare for slotting.
Parting is such sweet sorrow. Here we see the newly threaded screw being parted from the rest of the round stock.

Uhhhhhh, How do they put the slot in?

These little slitting saws are great for soft steel, aluminum and other soft metals/materials. Here we begin the slotting for the flat head screwdriver. 

What we end up with after slotting.  Could be a wider slot though any wider and it becomes easier to mess it up. 

In the white new front and rear stock screws for the Mosin Nagant 91/30

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