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Using a Router and 80 Lower Jig to Complete an 80 Lower

We bet you’re interested in knowing how, exactly, an 80 Lower Jig actually works! Putting tooling to metal can seem intimidating, but using an 80% Lower Jig is quite simple. Little to no mechanical experience is needed – the jig does most of the work for you! Let’s talk a brief summary of using a router and 80 Lower Jig to complete an 80 lower, shall we?


A breakdown of the 80 Lower Jig

Each jig is slightly different, but the general design and method of machining are the same. We’re using the Easy Jig Gen 2 to example this summary. The 80 Lower Jig consists of just a few primary components:


  •         Top plate (milling surface)
  •         Two side plates (drilling surfaces)
  •         Router attachment plate
  •         Set pins and screws
  •         Buffer tube support
  •         Drilling block


Setting up your handheld router

You’ll be using a handheld laminate router to mill out your 80 lower’s fire control group. You’ll first need to install your router plate on your router. Screws and holes are provided to secure the plate to the router. For most 80% jig builds and tutorials, the Porter Cable 450 Handheld Router is the tool of popular choice.


Setting up your 80 lower and 80 lower jig

You’ll need to set up your 80 lower jig and rest your 80 lower inside. This involves laying the top plate atop both side plates, securing them loosely with the provided screws and Allen wrench. The buffer tube support will secure to the side of the top plate with provided screws.


The 80 lower will rest between the side plates, underneath the top plate. The drilling block will then be installed atop the top plate. Instructions are provided to clarify how all plates, screws, and the lower should be oriented.


Drilling your 80 lower

The side plates and provided drill depth guides will do all the measuring and calculating for you. All you’ll need to do is secure the jig in a tabletop vise, grab the appropriate drill bits, and follow the instructions to determine which holes you’ll be drilling using the holes in the side plates.


Milling your 80 lower

You’ll only need to drill one pilot into the fire control group (using the drilling block) before you begin milling. Once your pilot hole has been made, you can grab your handheld router and end mill bit! The top plate provides depth guides which allow you to easily set your end mill bit’s depth.


The 80 Lower Jig will control your milling area, and the depth guides will dictate when you’re finished milling. The entire setup and machining process takes less than one hour!


Tips while completing your 80 lower

Setup and machining are easy, but there are some helpful tips and best practices you must follow, lest you end up with a low-quality AR-15 receiver. While drilling and milling, be sure to clean your jig and lower often. Canned air and plenty of machine oil should be used to clear debris away from your drilling and milling areas.


DISCLAIMER: If you are new to the world of DIY gun building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. At 80Lower Jigs, we are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.


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