Wednesday, November 24, 2010

Machining the bolt on the .50

I suppose an update is in order.
I had been working a steady schedule with my employer right up until the middle of September, wherein I had to work a normal "banker's hours" schedule. Between work and college classes, I would oftentimes get home from work/class too tired to work on any of my side projects, let alone blog about it. Now I am back on my normal schedule and actually have time to do my normal thing, which includes tinkering in the garage.

So, as of my last update, I had machined the tapered barrel guide, turned the barrel down to the diameter I wanted and threaded it for a muzzle brake and a barrel retaining nut. 4140 is pretty good stuff when it comes to machining, which is good because by the time I got done machining the barrel, barrel nut, and tapered barrel guide I had a HUGE pile of chips and curls left over. Next up was machining the bolt.

I started out with a 2" piece of 4140 solid round stock about 9 inches long, chucked it up in the lathe between a live center with a steady rest supporting the bolt material as well. I started to machine the area that would contain the chamber lugs by turning the last 1.75 inches of the bolt down to a 1.5" outer diameter.




I then measured an inch back and machined that 3/4 inch long section down to a 1 inch outer diameter.


Next up, I needed to machine the lugs on the bolt so that when a round is chambered and fired, the rifle doesn't blow apart. This needed to be machined on the milling machine. Despite my best efforts, I had to do some final finishing work with a file and some sandpaper. :\
More on this in a bit.....

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