80% AR15 lower jig

thingiverse

This is a jig I made for your 80% lower receivers. This fit my friend's Mil-Spec 80% lower and we used this to mill out the lower as well as my 80% receiver. Read first: The Lower jig itself is not designed for you to drill the holes (It may or may not be accurate). Which is why I made a file called "Trigger Hole Template" which comes with 2 pieces. This is secured onto the lower using the rear takedown pin. Make sure the top edge of the template is flush with the top of the lower (place it upside down at the edge of the table), and mark the hole with a fine tip sharpie or mechanical pencil. Next you should center punch the hole so the drill bit won't slip. Drill it out after milling. The 80 Depth Checker file is used to check for depth as well as making sure you're milling enough to the side. Mill it out until you're able to push the entire depth checker down. The oval cutout on the bottom of the depth checker is for the trigger hole. Trace it with a sharpie or something before drilling through. I just used a file for that part lol. Manually filed it. I used a harbor freight 1/2hp router and it was capable of milling out Aluminum. -Drill the holes last. -Drill bit needed for the trigger and hammer is a 5/32" drill bit. (I'd recommend going down 1 size and filing the hole manually to make the pins a tight fit.) -Drill bit needed for the fire selector is a 3/8" drill bit.- -Ideally, you want the pins to go in tight (duh), if it's too tight, use a fine file or 400-600 grit sandpaper wrapped around a toothpick/Q tip and slightly enlargen the hole. Milling Depth: Use the "Depth Checker" stl to check for depth. The hole on the bottom is used as a template to drill out the trigger hole. Mark it with a sharpie, and use a drill bit + file to get the job done.