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BigBoy1
05-16-2009, 07:04 AM
I have seen pictures of the Browning Automatic Rifle (BAR) Mono-Pod and tried to find an original one. After many years of looking, I never did find one. So I did the next best thing, I made one. I used the excellent pictures on page 281 of Jim Ballou’s Browning Automatic Rifle book, “Rock in a Hard Place”. Since I had the exact diameter from the socket in my Browning Automatic Rifle butt stock, I was able to scale the pictures in the book and then made a set of working drawings which I used to fabricate them. Mine is an accurate reproduction down to the snap-ball detent which locks the mono-pod into the stock recess.

The original mono-pods were made from steel but, I decided to make mine from brass for several reasons. The cutting tools to cut the required Acme threads are rather expensive (over $100) so I deemed more cost effective to buy the Acme threaded rod and nuts. The Acme threaded nuts were brass and I decided to make the entire body from brass because it has such a nice look to it. Also, since the original ones were made from steel, my brass one will not be mistaken or “passed off” as original.

On the original mono-pods, the body was made from one solid steel piece. Turning the brass body from a solid piece would be very wasteful, given the current price of brass as more than half of the price of a solid brass piece would end up as scrap. For this reason I used commercially available brass section very close to the sizes I needed and then silver soldered them together.

http://i163.photobucket.com/albums/t308/i422twains/BAR1.jpg
http://i163.photobucket.com/albums/t308/i422twains/Bar7.jpg
http://i163.photobucket.com/albums/t308/i422twains/BAR3.jpg
http://i163.photobucket.com/albums/t308/i422twains/BAR5.jpg

Bob Ford
05-17-2009, 01:35 PM
Looks nice and I like the fact it should not be mistaken for original.

Bob

dewat
05-20-2009, 10:13 AM
Nice machine work, good looking BAR too. Would you mind giving the details on making the ball detent ?

Thanks

Jim

BigBoy1
05-25-2009, 04:44 AM
Jim,

I cheated on the spring ball detent. I bought the spring ball detent "unit" from McMaster-Carr (Part No. 84835A12) and drilled and spotfaced the hole to the correct depth to permit the ball to lock but enough to permit the spring ball to compress and slide out.

This spotfacing process was trial and error. I made a dummy shaft from aluminum with the hole for the detent ball drilled completely through. The 5/16" spotfacing of the hole is critical as it determines the depth at which the detent will sit. I would spotface the hole a few thousands in depth, insert the detent and try it. The through drilled hole in which the detent ball sat was used to push out the detent for the next spotfacing cut. At a spot facing depth of 0.045" the ball would compress sufficiently to allow it to slide with difficulty into the hole and lock. At a spotfacing depth of 0.052" I stopped the cutting as the ball would slide easily into the hole and lock firmly in place.

On the actual stems, I spotfaced the area to a depth of 0.052" and then drilled the detent ball holes about 3/4 depth. I finished the holes with an end mill so the bottom of the hole would be flat. I was concerned about the tip of the drill breaking through the other side if I drilled the hole to the correct depth with the drill. When completed, the detent ball unit was pressed into place with a drop of Lock-Tite added to the hole just for ensurance.

dewat
05-25-2009, 08:36 AM
Bill,
Thanks for the info, it will be stored away for future use.

Jim