The best way is to use a hole finder which I believe someone had them for sale in the classifieds. Think about a pair of tweezers or calipers that match up to locate the hole.
How to attatch AMD65 receiver to front trunnion?
Hey everyone I recently had an AMD-65 parts kit assembled and my no dak spud receiver didn't have the front trunnion holes drilled in it. Is there a template or some kind of way to match the holes up on the receiver for drilling. I don't wanna screw it up or the receiver is trash as you only get one chance to drill the holes in the right place.
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Those things are an aviation tool used to locate rivet holes. They are also called "hole duplicators" and are available from Aircraft Spruce and Specialty Co, as well as other aviation parts / tool suppliers. The drill bushing is available in 4 or so sizes. They used to cost about $13.oo each but that was years ago.
Another technique for locating the hidden trunion holes under the new sheet metal receiver is to secure the trunion in a fixed vise via a mandrel through the barrel hole. Lock in the set up under your drill bit in a drill press or vertical mill. Then slide the reeiver over the locked down trunion, clamp securely, and drill the hole through the sheet steel.
VD
Another technique for locating the hidden trunion holes under the new sheet metal receiver is to secure the trunion in a fixed vise via a mandrel through the barrel hole. Lock in the set up under your drill bit in a drill press or vertical mill. Then slide the reeiver over the locked down trunion, clamp securely, and drill the hole through the sheet steel.
VD
you will need to pull the barrel from the trunion to line this up.
Take a post-it note and stick it to the bare trunnion with the sticky part over the serial number area. Use a pencil to make a rubbing over the holes to mark where they are. Carefully slide the trunnion into the receiver shell without disturbing the paper position, letting the shell slide between the trunnion and paper. The post it note is now over the receiver and the hole locations are clearly visible. Use an automatic center punch to mark the center of each one. Remove note and drill each spot slightly undersized. Step up in size until the hole is the right diameter. If it is slightly off, a Dremel can be used to hand shape the hole to match the trunnion hole. Once all holes are properly in place, drill completely through to the other side using the trunnion as a drill guide. Deburr holes and rivet.
The post-it pad method seems awfully easy and ingenius as well. I looked at the tweezer pictures and couldn't really figure out what was going on there.
DITTO on the above.Take a post-it note and stick it to the bare trunnion with the sticky part over the serial number area. Use a pencil to make a rubbing over the holes to mark where they are. Carefully slide the trunnion into the receiver shell without disturbing the paper position, letting the shell slide between the trunnion and paper. The post it note is now over the receiver and the hole locations are clearly visible. Use an automatic center punch to mark the center of each one. Remove note and drill each spot slightly undersized. Step up in size until the hole is the right diameter. If it is slightly off, a Dremel can be used to hand shape the hole to match the trunnion hole. Once all holes are properly in place, drill completely through to the other side using the trunnion as a drill guide. Deburr holes and rivet.
The post-it method is the cheap no tool way, the "tweezers" work well too. Essentially you have two flat steel straps hooked together with the open ended tips matching up. Drill a hole through the ends, lined up on top of each other. A small pin is fastened to one and the other is left as a hole. You put the pin through a rivet hole and slide the receiver over that strap, leaving the other on the outside of the receiver lined up with the pin. Mark the hole and repeat with the other rivet holes. You can buy a commercial version or make your own with some scrap steel straps.
I made a "hole finder by taking a 3/4" wide strip of sheet metal and a nail. Bend one end of the sheet metal strip around a 1/2" rod so it's like a "J" and cut both ends of the nail off and bend it like an "L" with the short side 1/2" long. Drill a rivet sized hole near the end of the metal strip and weld the nail so that the short arm sticks through the hole. You might have to bend it a little to get the nail centered perfectly in the hole. Once thats done, clip the "L" arm into a rivet hole inside the trunion with the metal strip on the outside of the receiver to show you where the rivet hole needs to be and mark/drill your hole. Since the barrels not there you can drill straight through using the rivet hole on the other side of the trunion as a guide for the other side.
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It's interesting to see all the different ways that everyone has attacked this problem. Will be trying one of these methods this weekend. Thx for all the different ideas.
It is best to first rivet in or fixture tight the mag catch/trigger guard to the receiver bottom. Next slide in the front trunion and adjust position to best fit with your choice of inserted magazine. When best position of the trunion is determined, then the hole marking for the receiver drilling can be done.
I made a set of the tweezers. Easy as hell the hard part is finding a pair of tweezers that are wide enough. Then i drilled a hole though them and screwed a 8/32 screw in one side. Done and works great!
Hey Harlan what happens when you adjust the position of the receiver on the trunnion after you've inserted the magazine catch and the receiver doesn't slide flush with the front of the trunnion? You end up with a gap between the receiver and the handguard.
I'm not Harlan, didn't stay at any motel last night, but here's how I do it:Hey Harlan what happens when you adjust the position of the receiver on the trunnion after you've inserted the magazine catch and the receiver doesn't slide flush with the front of the trunnion? You end up with a gap between the receiver and the handguard.
Use cap-head screws and nuts (or the special trigger guard threaded plates) to temporarily fasten the TG. If you end up with a gap, egg out the screw holes until you have both a) good mag fit and b) no gap.
Then, rivet the TG into place and set your receiver/trunnion holes. Good to go!
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