Tools for Completing an 80 Percent Lower (Required & Recommended)

Posted by 80-Lower on Aug 21st 2019

Tools for Completing an 80 Percent Lower (Required & Recommended)

This set of recommended of tools is part of our master guide:

How to Complete an 80% Lower (Router Or Drill Press & Jig)

Besides the 80% jig and included bits, we use some extra tools to make cutting and drilling our 80% lower easier and safer. Some of these tools are optional, but they could make the difference between a fun project with great results, and one that's difficult with poor results.

So, ready to build your first black rifle (or pistol) from scratch? You should first grab all this stuff for the workbench, then head over to our master guide! Let's take a look

80% Lower: Required Tools

1. Tabletop Vise

When it comes to completing an 80% lower, the two most important words are "precision" and "stability". You will definitely need a tabletop vise to secure your receiver blank and 80% jig. If you're using a router or milling machine to cut the fire control group cavity in your receiver, you'll be applying plenty of side loads to the receiver itself.


The jig will want to move around while you're moving your router and cutting the receiver. If this happens, your cuts will be off and your lower parts kit and trigger won't install correctly. The heavier your vise, the better. We recommend this 5" cast iron bench vise:

It's the vise we used because it's affordable, heavy and low-profile, so it stays out of our way. It has a wide opening (most jigs and receivers need at least 4.5" of clearance), and it has large slots on either side for bolting the vise to your workbench. If you're using a router to complete your 80% lower, then your jig should remain seated while you move the router around, making your cuts.

If you're using a mill or press, the opposite is true. Your tooling will stay put and your jig and receiver will need to move around instead. If that's the case, we strongly recommend using a cross-slide vise:

The X- and Y-axis adjustment knobs will allow you to quickly and safely adjust the position of the lower and jig underneath your mill or press. That means you don't need to physically move and re-seat the vise with every cut or hole you need to make. A cross-slide vise also gives you total control while cutting, reducing the chances of damaging your receiver and jig with your tooling.

2. Router and Drill or Drill Press

You'll need at least two of these three tools to cut your receiver and drill your lower parts kit's pin holes. Using a router means you'll be cutting your receiver side to side, or "milling". Using a drill press means you'll be cutting your receiver with vertical cuts, known as "plunge" cuts.

Router Recommendations

We wrote a full guide on Picking the Right Router for Your 80 Percent Lower Jig. If you want to keep things simple, we stuck with the Porter Cable 450:

This router works well with jigs and receiver blanks for a few reasons: It has a high-torque motor to make cutting aluminum safe and easy. It has an adjustment ring with very precise depth changes (1/64"), which is important for cutting the receiver. It has a 4" base, which is best for most 80% jig router plates and templates. It also has a 1/4" collet, which is most jig end mill bits required.

Drill Press Recommendations

We can't recommend a specific drill press, but we can recommend one important feature you should look for when shopping:

Tapered roller bearings. If you use a drill press to finish your 80% lower, we recommend buying a drill press that uses tapered roller bearings (pictured above). These bearings are considered high-quality, and they're more capable of handling radial (side-to-side) and axial (top-down) loads than cheaper ball bearings. You've probably read about others using their drill press to mill their receiver instead of making plunge cuts. They're likely using tapered bearings to do the job as safely as possible.

3. Aluminum Cutting Fluid

Using WD-40 or used motor oil as lubricant for your tooling won't cut it, folks. This is precision job that requires keeping your bits cool and sharp while they cut and drill. You'll need to grab some proper aluminum cutting fluid. Any proper cutting fluid will do, but we recommend and use Tap Magic Aluminum Fluid:

Tap Magic's fluid is nice because it helps produce a clean, polished finish on the surfaces you cut. It also does a great job of dissipating heat and keeping your end mill bit sharp. It doesn't gunk up your receiver with all the aluminum shavings like thicker oils might, either. Lastly, it's non-corrosive and non-staining. Some cutting fluids can stain untreated metals.

4. Canned Air and Brush

Speaking of aluminum shavings, you'll need to keep your 80% lower free of all that debris while you drill and cut. Letting shavings build up while you work will result in a dull end mill bit and a poor finish. Be sure to grab some canned air and fine brush - a simple paintbrush will do.

5. Gloves, Ear and Eye Protection

Yes, every firearm, jig, and power tool has the classic warning about wearing eye and ear protection. For this project, it's not a formality. You will need a good pair of gloves and adequate ear and eye protection, lest you end up with tinnitus or aluminum shavings in your skin and eyes. Cutting metal with power tools is risky business. Even if you're operating your tools safely, accidents can happen. Bits can shatter, drills can bind, and tools can go flying. Be safe.

80% Lower: Optional Tools

With the right required tools picked out, your project should run smoothly. There are plenty of optional tools that'll make machining even easier:

1. Spare End Mill and Drill Bits

You don't want to stop your 80% lower project half-way through cutting the fire control cavity, because your end mill bit broke. We strongly recommend investing in at least one spare set of drill bits and one extra end mill bit. Most jig makers sell replacement bits and tool kits, so this is an easy insurance policy to buy.

2. Painter's Tape or Masking Tape

Most 80% lowers ship with an anodized finish already applied. Setting your receiver inside your jig or vise could mar and scratch the surface, blemishing your new receiver. To keep things protected while you work, we recommend picking up some painter's tape or masking tape. Cover the exterior of the receiver blank with tape, ensuring that the top of the receiver is still flat and free of obstructions.

3. Aluminum Black Restorer

Even wrapped up in tape, your receiver blank will likely deal with some scratches and blemishes during machining and final assembly. That's not a problem! You're building a hardened battle rifle, after all. If you want that new anodized finish to keep looking new, though, a simple bottle of Aluminum Black will do the trick. This isn't just a cheap paint. Rather, this stuff reacts to raw aluminum chemically, giving it a blued finish that blends right in with an anodized or parkerized finish.

4. Roll Pin Punches + Gunsmithing Hammer

Once your receiver blank has been cut and drilled, it'll need a lower parts kit and trigger installed before it's ready for an upper assembly and buffer system. Installing your parts kit requires the use of special roll pins. These lil' pins are a real pain in the ass to install unless you have the right punches and a brass gunsmithing hammer. Trust us when we say it: Trying to seat these tiny pins with a regular hammer and a screwdriver, nail, or something else will result in said pins flying off into oblivion, halting your final assembly.


Need a quick summary?

  • The tools required for completing an 80% lower include:
    • Tabletop vise
    • Router or drill press
    • Handheld drill (if no press)
    • Aluminum cutting fluid
    • Canned air and a brush
    • Gloves, ear and eye protection
  • The optional but recommended tools include:
    • Spare end mill and drill bits
    • Painter's tape or masking tape
    • Aluminum Black restorer
    • Roll pin punches
    • Gunsmithing hammer

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, 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.