The Glock pistol has for long remained to be the most popular handgun for both beginner and experienced firearm enthusiasts, and concealed carry permit holders everywhere. If you’ve been considering building your own Glock and wondering how to go about it, you’re not alone. At some point in the past, building your own firearm required some level of technical skills and a few years of training on a CNC machine to accomplish a custom Glock build.

Until recently, building your own Glock 19 pistol was beyond the capabilities of the average gun owner. Now, with the right easy-to-find Glock parts and the revolutionary Polymer80 pistol frame, building your own Glock pistol is easy. With a few simple tools that you already have at your home workshop and some basic mechanical skills, you’re good to go.

Here’s our step-by-step guide to building your own functioning Glock pistol using a Polymer80 PF940 frame kit.

Why Would You Build Your Own Glock Pistol?

There are various reasons why people prefer to build their own handguns, including the personal satisfaction of creating something from scratch to wanting something that’s not available on the firearm market. For instance, Polymer80 offers Glock 80 percent frames in various different colors, something that you won’t find available on most handguns on the market.

After completing your Glock frame, you can go ahead and add your own custom slide, stippling or an enhanced trigger. For many years, competitive shooters and even the adventurous gun enthusiasts have been building their own Glock style pistols, and now you have the opportunity to compete or even show off your own hand-built Glock pistol.

Tools You’ll Need for the Custom Glock Build

There are a variety of ways you can use to build a Glock 19 pistol, and Polymer80, the company behind the pistol frame kit, provides detailed instructions on one proven method. For this method, which we’re also going to use here, you’ll need a few recommended tools including a Dremel tool, a drill press with an X-Y vise, a hand drill, a bit of fine grit sandpaper, a finishing file and a small hammer and punch to install the pins. These tools are readily available in any home improvement store.

The Polymer80 PF940 Glock Frame Kit

The Polymer80 Glock Compact frame is designed to match well with Gen 3 9mm, .357 SIG and.40 S&W Glock parts. For your custom Glock build project, you can go with either the standard Glock 19 parts or the other aftermarket components. You can easily find the completion parts you need to build a Glock 19 or another version in individual pieces or in toolkits from major gun supply shops across the country.

However, you can find several specialty suppliers offering everything you need from race gun parts to competition kits for your Polymer80 frame kit. When buying the Polymer80 PF940 frame kit, you’ll also get it with a jig and the appropriate drill and milling bits. The Glock 80 percent frame kit comes fully stripped with the trigger guard undercut to perfection. You also get a flared magwell that’s a major sales feature on the 5th generation Glock 19 pistol. The Polymer80 PF940C is provides a very solid basis for a tuned up Glock 19.

Parts You’ll Need to Complete Your Glock Assembly

Apart from the Polymer80 frame, you’ll also need other parts to complete your Glock build. They include:

  • Frame parts kit
  • Quality slide and slide completion kit
  • Stainless Steel barrel
  • Trigger set
  • Flared magwell for intuitive reloading
  • Lightweight sight system

How to Mill a Polymer80 Frame

Milling can sound complicated for a first-time custom gun builder, but the process is very straightforward when you follow the provided instructions that are available online. All you need is a drill press and an electric hand drill to complete the last 20% of the Glock pistol frame. There’s no complicated setup process for milling, considering that the jig provided keeps everything properly aligned as you work on your frame.

To avoid any potential problems during the build process, you’ll want to watch out for these points during your milling process:

  • Don’t drill the pin holes using a drill press on the cross vise. Only use the bench vise and hand drill.
  • Only used approved Loctite for contact with your Polymer80 pistol frame. Don’t use any super glue versions.
  • Avoid using any penetrating lubricants as they could damage your Polymer material. Don’t put acetone on the receiver, don’t utilize brake cleaner and only use regular gun oil or high-quality grease.
  • Don’t over tighten your jig on any vise otherwise you’ll be damaging the most critical part you’ll need to mill and build a Glock 19 pistol. Simply adjust the placement of holes to the pistol frame.
  • The grip is designed to be used on a regular bench vise for the pinholes standing upright, and on a cross vise also standing upright.

Finishing Your Polymer80 Glock Lower Receiver

When finishing the lower receiver or Glock frame, the end goal should be milling out the following with the assistance of the jig:

  • The three side holes on each side of the receiver for the pins
  • Mill the barrel guard and ribbing on the top of the receiver to easily allow the barrel and slide to fit later in the build process
  • Mill off the rear ribbing of the frame to allow the installation of the Rear Rail Module (RRM)
  • Install the Rear Rail Module provided with the frame parts kit
  • Install the Polymer80 Block Rail System that’s provided with the kit

Different milling techniques will result in different qualities of finish. You can either opt to use a milling machine or our recommended milling process of using a drill press with a cross vise, which is much faster and requires less time to set up. You also have more control over the milling process if the cross vise is utilized properly.

Preparation for Milling

Assuming that you’re using a drill press, a cross vise and bench vise to build a Glock 19 firearm, start by preparing the drill press. Ensure that the spinning chuck head of your drill press is attached firmly to the press by tapping it with a hammer. Otherwise, the vibration caused by the milling process can make the chuck head fall out, damaging your build in the process.

The drill press table should also be level. Install the end mill, cross vise on your drill press as it’s the most secure and fastest way to work on and finish the part. Compared to a Dremel tool, this method is more accurate. Understand that building a custom firearm takes a lot of craftsmanship, so don’t be in a hurry to get it done. Work methodically and precisely and ensure that every step is being done correctly.

The Main Milling Steps

Top Rail Block Milling Process

For this milling procedure, you should use the large end mill. Place the pistol frame in the jig and install the end mill in your drill press while ensuring that the table is properly adjusted, so you don’t have to move the end mill chuck head up and down. Mill the top of the Glock 80 percent frame fairly even but leave a little of room for more refining later on.

You don’t have to be aggressive at this point, or you’ll end up removing too much polymer which will ultimately cause problems as you build a Glock 19. If you’re not comfortable with milling away all the polymer, you can leave a little extra material to sand down by hand or use a Dremel tool to refine the top part of the Glock frame for a smoother and cleaner finish.

Barrel Block Milling Procedure

For many custom Glock builders, milling out the barrel block is considered the most complex procedure. Make sure to refer to the instructions provided to clearly understand the parts that should be removed versus those that should not be removed. Again, you’ll use the large end mill to mill off the interior part of the barrel block. Make sure not to remove the slide buffer that is usually indicated clearly on the frame kit.

Adjust your drill press so you can position your jig and Glock frame upright. The end mill should be pointing downwards towards the nose of the router jig and the frame and facing you. You’ll also want to make sure that the end mill and chuck don’t interfere with the jig as you slowly and carefully mill out the barrel block. You can also leave out a bit of material and finish it off with a ¼ inch round file later on.

Pin Hole Drilling Procedure

With the pistol frame firmly in the jig, go ahead and drill the clearly market side holes using a regular drill and bench vise as indicated on the instructions on how to build a Glock 19 using a Polymer frame kit. The drill bits for drilling the holes are usually provided with the Polymer80 Glock frame kit. Make sure to use a hand drill to individually work on and finish the three separate side holes on both sides of the frame.

Only drill one side at a time and don’t attempt to drill through both sides of the pistol frame from one side of the router jig. In short, you should flip the jig to the other side in the vise once you’re done with the first side and drill the other side separately. Pay close attention to the M3 and M4 hole indicators on the router jig. When drilling, make sure that the jig is not over tightened to avoid displacing the drill holes. The drill chuck should not be hitting the vise while you’re drilling.

Installing the Locking Block Rail System

After you’ve finished milling the pistol frame, the next step is installing the locking block rail system. This is a hardened stainless steel Glock frame component that features a design that efficiently incorporates the slide rails and locking block, and also provides the needed strength for the slide to stop the block buffer.

The locking block is easily installed by tapping it slowly into place, ensuring the proper alignment. Use one of the provided black pins (3mm x 25mm) and tap it with a hammer all the way through the side hole and front legs of the locking block rail system. Make sure the pin is equally distributed across the pistol frame.

Choosing a Trigger for Your Custom Glock Pistol

Once your Glock frame is milled and drilled, it’s time to consider inner components along with which trigger you’ll be using. Some firearm enthusiasts like the factory built Glock trigger while others want a lighter, smoother and more consistent trigger that provides a more distinct let-off. As you build a Glock 19 pistol, keep in mind that what matters most when choosing a trigger is your pistol’s intended purpose.

Do you want a daily carry gun? Are you actively engaged in all-out race gun competitions? Maybe you want something in between. Your regular firearm use will affect your choice of the trigger, so choose carefully. The Polymer80 PF940 pistol modular design makes it easy for anyone to install a trigger of their choice.

Installing the Frame Parts Kit

With your choice of the Glock pistol trigger already nailed down, it’s time to install the necessary parts into your Polymer80 frame. The frame parts kit, the trigger set, trigger mechanism housing and other parts are often sold separately from the Glock frame. The frame parts kit includes a magazine release, a slide stop, a locking block, rear rails that are unique to Polymer80 and, of course, the trigger kit. Assembling the frame is not challenging so long as you know what part needs to go where. The procedure requires attention to detail to ensure correct installation.

Picking the Right Slide for Your Glock Frame

Having finished the Glock pistol bottom half, you should now be ready to focus on the upper side. The Polymer80 pistol frame easily works with slides that fit Glock factory pistols with similar sized pistol frames. You have numerous options in the firearms market to choose from when it comes to buying Glock frame slides.

For starters, select a plain, factory slide or a quality aftermarket slide that comes with any combination such as a mounting slot for a red dot sight, serrations and weight-saving cutouts. There are even frames that come with blank exteriors that you can custom-machine to exactly how you want them to look like if you do have the resources and skills.

Selecting a Barrel for Your Glock Pistol

Getting the right barrel for your Polymer80 Glock pistol is easy, though the number of options available is considerable. Are you looking for an aftermarket barrel, Glock factory barrel, threaded muzzle, conventional rifling, fancy exterior pattern or one with extra features? You’ll need to consider the kind of shooting you plan to do with your pistol to identify the most suitable barrel for your firearm.

Choosing Sights for Your Glock Build

You can’t build a Glock 19 pistol without the right sights. Your custom pistol will not be effective if you can’t line up the bore with the aimed target. The good thing is, almost all factory built and aftermarket Glock slides and sights are universally compatible. What this means is that you have lots of options when it comes to choosing sights for your Glock pistol.

Whether you want white dots, basic black, ghost ring, shallow ‘V’ rear, Tritium night sights, fiber optic, big dot front or a slide with a cutout to allow for a mini red dot sight, you have all the time to choose the most suitable sight for your pistol. Building your own Glock pistol means that you can choose the sights that work best for you.

Assembling Your Glock Pistol Slide

With all the parts you need to go on your slide, all you need now is some simple tools and simple work on the bench to put them all together. Start by installing the safety plunger, firing pin or striker assembly, extractor and the accompanying plunger spring and bearing, slide back plate and the sights. This may seem like a lot of work to do but is basically simple.

Testing Your Custom Glock Pistol

With everything now installed, your Glock pistol should now be ready for testing. You’ll want to make sure that no loaded mags are used to ensure safety. Proper Glock pistol tuning and fitment is critical to ensure that your custom built pistol is functional and performing as expected. Expect the whole system to be stiff during the initial testing phase. Use the right firearm lubricant along the pistol slide rails and other friction points to ensure smooth functionality.

If you already have an idea of how a working Glock frame and upper slide feel, then you should have a clear baseline for the actual feeling you’re attempting to achieve with your new custom Glock build. Don’t put the magazine during your first few tests and don’t use a loaded magazine. Rack the entire system back & forth several times to ensure it’s working as expected.

Once you have your Glock pistol consistently going to battery position, you can now head to the gun range and test it with several live rounds. Be careful as you have fun and allow the system to work itself smoothly together. Most testing issues result from incompatibility issues. Ensure that you choose a compatible Glock slide and barrel combo.

You can now say you’re a proud owner of a pistol you’ve built and tuned yourself.

Buy Quality Glock Parts

If you’re searching for essential Glock 80 percent frame parts that will allow you to build a Glock 19 pistol, 5D Tactical is your trusted partner for essential Glock parts. We stock the highest quality 80% Glock parts and components needed to complete your custom build at home. Shop our Glock lower parts kit, Glock 19 complete upper, Glock 19 compatible Polymer80 frames, Gen 3 stripped side and our complete Glock 19 80 percent build kit through our online store.