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Posted: 8/9/2006 4:10:18 PM EDT
 Build tips and photos helped me greatly to assemble my latest "Retro" Build. But it left me with 2 questions: What specific tool can compress, hold and drive a split pin like the bolt release catch pin without crushing it or losing it while the pin's being driven into place? My regular pin vise failed miserably.....wouldn't compress the pin, and the pin kept slipping deeper into the vise chuck rather than going into place. What specific tool compresses the front pivot pin detent into a compressed position and still allows the pivot pin to be placed into position..without launching the spring-loaded detent into space? Everything else went together fine. Crushed the first bolt release pin and lost the first pivot pin detent. Luckily I had some small parts to replace the parts wounded in action. Part numbers or tips, please? |
| Bushmaster sells this little tool to help install the pivot pin. I believe it is inserted in the opposite side of the lower that the pin will be inserted. It presses down the detend and you insert the pin while pushing out the tool. I managed to just use the pin to depress the detent without buying a tool, though it took a while and a lot of cursing. Try doing it inside of a large plastic bag just in case it gets away from you if you don't want a tool. Just in case it does get away, you can grab one of these. I had to because my detent was destroyed. |
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Specs for making a front pivot pin installation tool are in a USMC Tech Manual (TM 05538C-23&P/2, p.E-4) that I got with my parts kit from M&A, and probably in some similar manual from the Army. It's basically just a rod the same size as the pivot pin holes, with a hole drilled near one end and across its diameter that is just slightly larger than the detent pin/spring. To use it you put the tool through both pivot pin holes, line the cross-hole up with the recess for the detent spring & pin, drop the spring and pin down the hole, press the detent pin down below the other side of the tool (use a toothpick, drill rod, whatever) and rotate the cross-hole out of alignment. Now the detent pin is captured in its recess, under spring pressure, just waiting for you to use the pivot pin to press the tool back out of the pivot pin holes. The detent pin will snap up into the detent slot in the pivot pin when the slot comes into alignment. The Tech Manual calls for making the tool out of steel which is then hardened and tempered. I made mine out of a 1/4" wooden dowel rod (hey, it was Sunday night and I was in a hurry) which worked OK, but a harder material would have been better. For my next build I'll make one of the tools out of aluminum or brass or maybe plastic, just to say I did it. |
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I've got one of the pivot pin tools and it's been a waste of money IMO. I have more trouble using it than if I just use the pivot pin to press the detent in and slide it through. Everybody has their own ideas, but that's what I've found. As for the bolt catch pin and every other roll pin on there, I use a roll pin starter punch from Brownells to get them started then a normal roll pin punch to finish them. The starter punches have a hole in the end that holds the pin in place. The other roll pin punches have a dimple on the end that fits into the hole on the end of the roll pin to keep the punch lined up on the pin and prevent the end of the pin from deforming. Specifically for hte bolt catch roll pin I use the bolt catch punch that Adco sells. It is a roll pin punch with a half round handle section so you can get lined up on the pin correctly without bumping against the side of the receiver. Check out Adco's tools page at www.adcofirearms.com/acc/ProductLineB.cfm?brand=schuster&caliber=3&page=acc. The take down punch is at the top of the page. Scroll down and they also have some roll pin starter punches. |
I use a 1/4" clevis pin ($1-2 at the local hardware store) to install the front pivot pin. Stick the clevis pin throught the receiver and line up the hole. Drop in the spring in and place the detent on top of the spring. Push down on the detent with a small allen wrench or roll pin punch. Then turn the clevis pin so it locks in the spring and detent. I then slowly push the clevis pin out using the front pivot pin. The detent locks in to the pivot pin and it's installed. 
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i set the spring/detent into place with my fingers and then use an extra piviot pin from the other side to hold the detent in place. then set the new piviot against the one holding the detent and slowly push it into place. be sure to hold the new piviot pin firmly against the fence until the piviot pin starts into the hole. ..works great for me.  
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Akars, heh, iw as about to say "you installed it backwards" til I read your comments. not a bad tip at all! as for driving the roll pins, you can get roll pin punches from Eagle Firearms for like $10. I used those a little, and some vise grips wrapped in electrical tape to drive the bolt catch and trigger guard roll pins pretty easily. |
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These make assembling the lower much easier: www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=5551&title=ROLL+PIN+PUNCHES 3/32 is #3 Roll pin punch (for bolt release pin) item #230-100-003 #3 Roll Pin Punch $4.05 1/8 is #4 Roll pin punch (for trigger guard pin) item #230-100-004 #4 Roll Pin Punch $4.15 Small item shipping $3.95 total delivered $12.15 Prices current as of 8/11/2006 |
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