Lower Milling Instructions – Hybrid-80 (Tennessee Arms) Polymer Lower

The following instructions are for the Hybrid-80 Liberator AR-15 lower. I copied them from Guns80.com. These lowers can be found at Guns80.com, Tennessee Arms, or Brownells.

Getting Started. 
You will need a few tools to finish your Hybrid 80% Liberator. We recommend a drill press, cross slide vise ( x,y vise), and a rotary tool (similar to a Dremel)

Using the supplied 5 smaller screws, enclose the entire jig securely. This will ensure all the holes line up exactly where they need to go. Secure the entire assembly inside a vise during machining.

Trigger Pocket

The trigger pocket is by far the most critical portion of the machining process. We recommend the use of a drill press and a cross slide vise ( x,y vise). The most important thing during this is patience. This is not an easy thing to do by hand, that is why we suggest the cross slide vise ( x,y vise). Remove material with the end mill in .25” steps in the shape of the fire control pocket. Remove material until you reach a final depth of 1.22″. Use of a rotary tool and sandpaper can help smoothing the material to a finish.

Trigger Hole Guide

The trigger hole guide is simply to make the hole for the trigger to go through. Using the drill bit (or 5/16” end mill) carefully make the hole all the way through the bottom. Afterwards, clean the edge using some sandpaper, a file, or a rotary tool.

Trigger Pins/Safety Selector

When drilling the holes for the trigger pins and safety selector DO NOT drill all the way to the other side. Flip the assembly over and drill from each side. The jig is designed to center the part on the bit. So, before securing the jig to the work surface, center the bit on the part with it not moving, to ensure it is aligned. Do not reuse the jig after assembly. It is designed for a single use only.