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By Steve Vikfors - "Ace in the Hole" Gunsmithing - Sonora, CA
Several weeks ago a customer of mine requested that I jewel the bolt on his Remington Model 721 in addition to some other work I was doing. I explained that it would take some time, as I did not have a jig any longer. He told me to take all the time I needed as he was in “no hurry”. After searching the Internet for a few days I only found one jig that was available, after reading a few reviews I knew it was not for me. Dad always told me, “buy good tools, take care of them and they’ll last you a lifetime”. It took me several days to come up with the sketches to build my own Jewelling Jig. First the frame.
I live in the Central Sierra Foothills of California, in the small town of Sonora. It would take a 2 1/2 hour round trip to Modesto to get the frame material.
I made the frame from 6061 aluminum, .500” thick by 4.00” wide. The base piece is 10.75” long, each end piece(s) are 6.00” long/high. The “bushings” (discussed later) are centered and located 1.5” form the “top” of each end piece and pressed into place. The ends are held to the base by five- (5) .250”x 1.5”x 28TPI Button Head bolts with washers at each end. There are other ways to attach the ends to the base but this is the path I chose.
Picture 1 shows the completed jig with a Remington LA bolt that is nearly complete, I chose to use Tom Menck’s .250” Damaskeening Tool from Brownell’s (590-011-250) for this project. It was a good choice. The “Indexing” end consists of several parts.
The “Indexing Wheel” is a 36 tooth timing gear from a Chevy 350 (under $20). It is attached to the main shaft by an aluminum “hub” made from 1.625” round stock I had on hand. The aluminum makes it “self-locking”. It’s attached with a .250” x 28TPI bolt. The main shaft passes through a bronze flanged bearing (hardware store) that has a 1.00” OD and a .750” ID. The shaft is 2.665” OAL, made from 1.125” 303SS, the portion passing through the bushing it is .749” (polished) by 2.00”. On the outside it was left at 1.125” x .420” for the “bearing” hub. Then reduced to .749” by .245” to attach the Indexing gear. On the “inboard” portion of this shaft is a .750”ID bronze washer and an aluminum spacer. This spacer is .980” OAL, 1.00 OD, and .750” ID. It was made about .010” short of the “exposed” main shaft after it is mounted in the bronze bushing with the bronze washer attached. This allows free rotation after the Bolt Adaptor is attached.
The Bolt Adaptor can be made to fit any bolt body; I chose a threaded design to simplify “locking” the bolt body in place. This Bolt Adaptor is .500 x 13TPI for Remingtons and has a .695” hub to fit into the bolt body. The Adaptor is 1.150” OAL, major diameter is 1.00” with a .498” by .165” hub fitted into the main shaft and held there by a .250” x 28TPI bolt. A simpler adaptor could have been made with a pin that “locked” into the bolt body’s “cocking” notch. I chose the threaded method to have better tension control at the bolt face “end” of the jig.
The “Bolt Face” end of the jig consists of several more parts. First is the 303SS bushing I made to mimic the bronze bushing at the other end. Other than material the main difference is that this bushing is threaded .750” by 16TPI. This is to accommodate the shaft that allows for adjustment for different length bolt bodies. A plastic knob and hex nut were found at the local Orchard Supply along with another bronze washer to “lock up” the shaft once it was adjusted for tension. This shaft is 4.175” OAL, threaded .750” by 16TPI. The “business” end is counter bored .250”, a “hub” to accommodate the “Bolt Face Adaptor” and is left at a diameter of .750” by .465“ “wide“. Between the “hub” and the threaded portion is a reduced section (.775”) to allow the shaft to be “backed out” to change LA bolts. I discovered this was a necessity when I switched from a SA blot to a LA (design whoops!). It was not an easy fix and should have been planned on as this shaft was being made.
The Bolt Face Adaptor mirrors a cartridge case head (to match bolt face being worked), in this case a 30-06. One of the pictures should tell the story; the opposite end of the adaptor has a .250” “spud” that fits into the threaded shaft’s .250” counter bore. With this design I remove the ejector but not the extractor. I went this route because I didn’t feel comfortable putting anything into the firing pin hole. On second thought, a lot of work could have been saved with a different design. Using “Newlon Precision” brass “Crown Savers” and a simple rotating sixty- (60) degree point on the shaft would fit allow the “Savers” to fit the firing pin holes without damage and possibly eliminate the removal ejector.
The last part is the “Index Lock Housing”. I made this from a piece of SS round bar, 1.5” OD and 1.675” long. The spring loaded lock I bought from McMaster Carr, their P/N 84935A25 and is threaded 1/2 x 13TPI, about $14 plus S&H. The first step in the housing was to “through bore” it for the 1/2 x 13 thread. Once this is done and threaded past a depth of .750”, the outer profile is up to one’s own taste. I reduced the diameter of the housing around the lock body so that it would not interfere with the lock’s operation. The “through bore” should be “back bored” from the mounting base side, .575” by 1.015” deep. The Index Wheel passes through a milled cut in the Lock Housing that is .925” deep as measured from the outer major diameter of 1.5”. This slot is .540 wide and is indexed .490” from the mounting base of the Housing. The housing is mounted with two bolts to the end plate of the frame in a milled vertical slot approximately 1.5” long by .250” wide. This allows for vertical adjustment and ware over the 1.250” outer bolt spacing when they are installed. It also allows for a nice firm connection between the lock and the Index Wheel.
Mounting to the mill or drill press table is completely a personal choice. I chose two (2) aluminum flat bars, I milled the back of the bars about .125” deep to fir snugly over the base. They are attached to the table with bolts and “T” nuts.
I can not tell you how many hours or the total material cost that went into this project. It was a fun project with a lot of satisfaction in the end. Besides, Dad would be proud, this is a “good tool”.
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