Real time inventory. No backorders. Ships within 3 - 5 Business Days!

How to Cut, Drill, and Finish a P80 Frame

How to Cut, Drill, and Finish a P80 Frame

Posted by 80-Lower.com on Feb 25th 2022

Welcome to our two-part series on how to build a Polymer80 (GLOCK-compatible) handgun! We're going to cover:

  • Frame compatibility - which should you pick?
  • Parts and tools you need to build your pistol.
  • The steps required to fabricate the frame.
  • Finally, the steps required to assemble it.

We have much to cover. Let's dive right in.


"Which frame should I build?"

You're probably picking a Polymer80 handugn frame becased on which GLOCK handgun series it corresponds with. So, select the appropriate frame and jig below based on which GLOCK model you want:

Each polymer 80 frame kit includes:

  • 80% pistol jig
  • Polymer 80 pistol frame
  • Locking block rail system
  • Locking block rail pins
  • Trigger housing pins
  • Rear rail module
  • End mill bit
  • Drill bits (M3, M4)

Once you've picked out your kit, it's time to get started with setting up your frame, jig, and tooling. Then we can start machining!


Tools for Fabricating Frame

Pictured below are required and recommend tools for fabrication. Once your frame is finished, we'll get into tools needed for assembly:

  • Cross-Cutting Pliers. These pliers provide a clean cut for removing extra tabs atop the unfinished frame.
  • Dremel. A Dremel provides a great way to sand, cut, and clean up rough edges on your frame.
  • Files. Files are needed for final finishing to ensure your slide and barrel can install easily.
  • Small screwdriver. A small screwdriver will help insert and remove certain parts as you test-fit them.
  • Safety glasses. Always wear eye protection when you're cutting or drilling material.

OPTIONAL: 3/8" Drilll Bit + Drill Press. A bit and drill press provide an easy way to remove most of the material for the barrel block area. This step can be easily completed without a drill press. It will simply take longer.


(Video now available!)

Part 1 of 2: Fabricating The P80 Frame

Let's look at the major steps you need to complete on your 80% pistol frame:

  1. Drill the trigger pin hole.
  2. Drill the locking block pin hole.
  3. Drill the trigger housing pin hole.
  4. Cut the slide rails.
  5. Cut the barrel block.

Step 1: Jig and frame setup

Your frame and jig will arrive pre-assembled. We recommend quickly disassembling the jig and inspecting the frame before beginning. To open the jig, gently pull up on the top plastic tab. The jig will separate into two halves. After reassembling the pair, tape the front, back, and bottom of the jig to ensure it stays tight during fabrication.

NOTE: Opening the jig or remove the frame from the jig during fabrication may result in misaligned pin holes! Do not open the jig until all pin holes are drilled.

Step 2: Cut the slide rails

The top of the frame cannot accept a slide or barrel until excess plastic is removed. We've highlighted those plastic tabs - present on both sides of the frame - above. Removing these taps is easily accomplished using side-cutting pliers. 

NOTE: You can also use a Dremel to cut the tabs. We example this in our "how-to" video:

We've we found the heat generated during cutting may produce a rough finish. The risk of removing too much material is also high. We therefore recommend cutting the tabs by hand and using a Dremel lightly, for final finishing.

Although slower, finishing the slide rails with a flat, fine-tooth file will produce the best results.

Step 3: Drill The Pin Holes

WARNING: Do NOT attempt to drill pin holes through one side only! Doing so will ruin your frame. You must complete each pin hole by drilling halfway through the frame using both sides of the jig.

If you attempt to drill your frame's pin holes by going through one side of the jig, you will wind up with misaligned holes. It's guaranteed. Trust us and other customers' feedback.

Take your time and follow these best practices:

  • Run your drill on a low RPM to reduce heat and warping.
  • Plunge the bits up and down while drilling to remove debris.
  • Measure depths while drilling to ensure you don't drill too deep.
  • Keep your frame and jig secured in a vise, but do not over-tighten it!
  • Complete all three holes half-way on one side before flipping the jig over.

After drilling, visually inspect each pin hole to ensure most debris is removed. Check that all holes run through the frame like above. You may notice small bits of plastic stringers left behind. These can be cleaned up with a few light passes from a small round file.

Step 4: Cut the Barrel Block

With all three pin holes drilled, we've arrived at the final fabricating step: You must cut the excess plastic away from the barrel block seat.

WARNING: Only remove material up to the indentation! Reference the tip of the screwdriver above.

Only this thinner section of plastic should be removed from the frame. Removing material past this point will destroy your frame. This area can be cut easily with a Dremel or drill press. Using a drill press and drill bit provides a quicker and more effective cut.

To drill out the area, first secure your frame and jig vertically in a work vise. Make sure the bit does not plunger far past the plastic, or it will damage the rearward portion of your frame.

With most of the excess plastic removed, your frame should look like our example above. This area can now be further shaped, filed, straightened with hand files. Once finished, your fabricated area should run flush with the rest of the barrel block's seat.

Fabrication is Complete!

You should test-fit the Rear Rail Module and Locking Block Rail System by resting them inside the frame. You may need to remove debris from inside the frame that's preventing installation, often left behind by drilling pin holes. You may clean up the exterior of all pin holes, and the inside areas you cut, using 2,000-grit sandpaper. Wet sanding will produce the smoothest finish.

Part Two (how to install your P80 parts kit) is coming soon!



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 80-lower.com, 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.


We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.