Having a little anxiety or uncertainty about completing your first AR-15 receiver using an 80 lower jig? You’re not alone! Many see the tooling, router, and fast-moving metal and take pause. If you did, that’s okay. Here are some helpful 80 lower jig tips and tricks to help get you started!
1. Know the steps before machining
Many first-timers buy up everything they need to build their AR-15 – the 80% lower, the jig, lower parts kit, upper receiver, and buffer assembly – and jump right into the project. Although machining an AR-15 receiver with an 80 lower jig is easy, it requires patience, careful measuring, and safety. Before you slap your lower into your jig and start drilling and cutting, get to know the entire process first. Our 80 lower jigs all include written instructions. Many also come with video tutorials.
Un-box everything, taking note of what’s what. Watch the tutorials and read through all the steps before you get started. It’s much easier to confirm you’re machining your lower correctly instead of trying to figure it all out while you go along.
2. Buy the right 80 lower jig
There are many ways to machine an 80% lower. There is only one right way to do it: With an 80 lower jig. Could you use a drill press? Sure, but if you know how to measure and size up your X’s, Y’s, and Z’s, you probably don’t need our help. For the rest of us, the 80 lower jig will do the measuring and most of the work for you. We even paired up our top 80 lowers with the right jig and tooling so you can ensure you have the right stuff for your project. Check ’em out here!
3. Take your time while drilling and milling
We know you’re excited to build, and we’re excited for you! Building an AR-15 from scratch is a rite of passage in the black rifle community, but you shouldn’t rush. Take your time setting up your drill bits and end mill bits. Ensure your bits are properly seated in your hand drill or router. Ensure your holes are properly marked before drilling too. We recommend investing in a center punch to get all your pilot holes started.
4. Invest in some extra bits and tooling
Machining metal – especially billet or forged aluminum – causes tooling to develop wear-and-tear pretty quickly. You should also only use the tooling provided with your 80 lower jig. We sell replacement end mill bits and drill bits for this exact reason! Take a look and consider buying some spares. After all, you’ll probably find yourself starting a second build after you finish this one (trust us).
5. Set up a good gunsmithing station
Building an 80 lower at home qualifies you as an amateur gunsmith, and no good gunsmith does work without the right tool bench. We strongly recommend investing in these gunsmithing tools. Ideally, you’ll want the following to ensure your project goes smoothly:
- Drill Press Bench Vise
- AR-15 Build Mat (includes a full schematic!)
- Gunsmith’s Brass Hammer (for those little roll pins)
- Handheld Router (The Porter Cable 6430 was specifically designed for 80% lowers and their guide plates!)
We also strongly recommend investing in some machining lubricant and canned air, or setting up a compressed air line. The debris created by your drilling and milling can quickly overwhelm your tooling. Excessive build-up can cause tooling to overheat, and you could cause damage to your jig or lower. Some jigs (like the Easy Jig Gen 2 Multi-Platform) even include a shop vac attachment for easy clean-up.