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How to Build Your Own 1911 at Home

Posted by 80-lower on Dec 20th 2018

How to Build Your Own 1911 at Home

The 1911 needs no introduction. If you’re reading this, you’ve already made the commitment to build one of the greatest handguns ever made. Rest assured, building your 1911 at home is also 100% legal as long as you can otherwise legally own a firearm. We’ll walk you through everything you need to know.

So, without further ado, here’s how to build your own 1911 at home!

First, Buy a 1911 Build Kit

You can build your 1911 piece by piece, investing in an 80% 1911 frame (also called a frame blank), then a slide, then a parts kit. Or, you can pick up everything you need in one kit.

A 1911 Build Kit includes every part required for this project, and buying a kit guarantees all the parts you pick up will work together without issue. This is especially important if you decide to build a Commander, or a gun chambered in 9mm instead of .45 ACP.

What's Included

Everything in our 1911 Build Kits is made in the USA from Chromoly steel and forged 7075 T6 aluminum. We offer kits configured in .45 ACP or 9mm, and we offer frames in 5” Government and 4.25” Commander profiles. Frames can be purchased anodized with a matte black finish or raw. Here’s a complete breakdown of everything in your kit. If you don't buy a kit, this is everything you’ll need to build your 1911:

  • 80% 1911 Frame
  • Slide
  • Slide Stop
  • Barrel, Link, Pin, Barrel bushings
  • Adjustable Trigger
  • Grips
  • Grip Safety
  • Grip Screws & Bushing
  • Hammer
  • Hammer Strut
  • Sear
  • Mainspring Housing
  • 11-Piece Pin Set
  • 7-Piece Spring Set
  • Magazine Catch Assembly
  • Firing Pin Stop
  • Extractor
  • Thumb Safety
  • Disconnector
  • Plunger Tube
  • Ejector
  • Recoil Guide
  • Novak Fixed Sights
  • 8-round Magazine

Next, Buy a 1911 80% Jig

The 80% jig is the drilling template and cutting tool for finishing your 1911's frame blank. The jig we sell comes from Stealth Arms and it's also made in the USA. It's easy to use (requiring no special tools) and it's made to work with any of the available frames and build kits we sell. The jig will hold your 80% frame in place, showing you where to drill and cut the frame blank for the slide, barrel, and parts kit.

The jig includes:

  • Right-hand side plate
  • Left-hand side plate
  • Cutting car
  • Spacer block
  • Cutting handle w/ knob
  • Rail cutting blade (installed)
  • Barrel seat cutting blade (installed)
  • (2) set screws for securing frame and jig
  • #35 drill bit
  • #22 drill bit
  • 5/32 Allen wrench
  • 3/32 Allen wrench
  • (1) 1-oz. bottle cutting fluid

The only other tools you'll need for this project are a vise, a black marker, and a drill press or vertically stabilized hand drill. Using the jig requires no milling machine or specialty tools. All cutting is done by hand with the car. The carbide blades used for cutting the frame are already installed on the cutting car, pictured above with the black handle. 

Let's Machine Your 1911 Frame!

With the build kit and jig ready to go, it's time to start cutting and drilling our frame blank. We'll walk you through each step with illustrations. Go ahead and download the written instructions, too.

The steps required to complete your frame for final assembly are simple:

  •         Cut the slide
  •         Cut the barrel setting
  •         Drill the hammer pin hole
  •         Drill the sear pin hole

#1: Assemble the frame blank and jig

Parts required:

  • RH side plate
  • LH side plate
  • 0.157 dowel pin
  • 0.201 dowel pin
  • M5 x .8 Allen-head bolt

Grab your frame blank and both jig plates. Orient each plate so the interior cut-outs on each plate line up with the shape of the frame. Each plate is engraved at the barrel end, "LH" and "RH".

With the frame and plates oriented, insert the small dowel pin through the rear-most hole on the frame's beavertail. Insert the large dowel pin through the top-most hole above the trigger guard. Press each plate onto either side of the frame.

Secure the frame and jig together using the provided Allen-head bolt and key.

#2: Drill the hammer and sear pin holes

Parts required:

  • #22 drill bit
  • #35 drill bit
  • Drill press or vertical drill

Lay the frame and jig assembly on its side. Your assembly must be perfectly flat and leveled under your drill. If not, the holes will not allow you to assemble your finished frame and parts kit.

Insert the #22 bit in your drill's chuck and tighten it. Next, orient the bit so the hammer pin hole on the jig side plate is lined up with the bit, pictured below.

WARNING: Do not attempt to drill either pin hole by going through one side completely. 

The drill bits will flex, and the finished pin holes will not be aligned.

Instead, drill each side of each pin hole by only going half-way through each jig plate. Drill the hammer pin hole using bit #22, then repeat the same step for the sear pin hole with bit #35.

#3: Prep the cutting car blade for the slide rail

Parts required:

  • Cutting car
  • Allen wrench

With your pin holes drilled, half your machining is already completed! Pretty easy, right? This next step isn't difficult, either. Grab the cutting car and look underneath. Note the set screw holding the guide boss and slide cutting blade, pictured below.

Grab the appropriate Allen wrench and loosen the set screw. This loosens the cutting blade.

Push the loose blade up into the guide boss, so it's sitting just slightly inside the bottom opening.

Re-tighten the set screw.

#4: Install the adjustment knob and handle

Parts required:

  • Cutting handle
  • Adjustment knob

Orient the cutting car so it's top-down with the front facing away from you. Insert the handle in the bottom-right hole and thread it in place until tight.

Next, insert the cutting blade's adjustment knob in the top-right hole and thread it in place:

The adjustment knob will thread down onto the top of the guide boss until it's seated. Once threaded on completely, rotating the adjustment knob further will adjust the depth of the slide rail cutting blade underneath.

#5: Install the spacer block into the LH side plate

Parts required:

  • Spacer block
  • Bench vise

Before cutting the slide rails, the jig and frame blank need to be secured in your vise. This applies pressure to the assembly. To keep the integrity of the jig, insert the spacer block into the side plate that are you are not cutting. If you want to follow the illustrations, insert the spacer block into the LH side plate as shown:

Next, grab your vise and get the work bench ready for cutting. Be sure to have plenty of lubricating oil and make sure your work area is well-lit.

#6: Secure your jig in the vise and lubricate

Parts required:

  • Bench vise
  • Lubricating oil

Orient the frame and jig assembly so the LH side plate is secured in the jig. Ensure the barrel end of the frame is pointed toward you:

Once secured, apply plenty of lubricating oil to the entire surface of the RH side plate. The cutting car will be directly contacting (and rubbing against) each site plate. Oil will ensure the cutting car glides freely atop the plates.

#7: Set the car atop the jig and "zero out" the blade

Parts required:

  • Cutting car

Rest the cutting car atop the RH jig side plate, but don't move it yet. The guide boss containing the blade should sit inside the open slot on the jig's side plate:

DO NOT TRY TO CUT THE FRAME BEFORE READING THIS.

We need to "zero" the blade, which means getting the blade just touching the frame. This will be our starting position. First, make sure the car is resting flat on the jig, as pictured above. If the car isn't resting flat, the blade is probably sticking out. Back it off by rotating the knob counter-clockwise.

Once the car is flat on the jig, slowly push it away from you. This is the cutting direction. Stop moving if you feel any friction. This means the blade is touching the frame. If it's touching, back the blade off by rotating the knob counter-clockwise. Do this until you can't feel the blade touching the frame. Then, reset the cutting car by bringing it back to the barrel end of the frame, nearest to you.

Once again, slowly push the car forward while turning the knob clockwise to lower the blade. Do this until the blade is just touching and you feel a little friction. Stop moving when this happens.

You've found your zero.

#8: Mark the zero/staring position on the jig

Parts required:

  • Bright permanent marker

Now you need to mark the starting position on the cutting car with a marker. An example starting position is illustrated below, in red. See the notches on the cutting car, underneath the adjustment knob? There are ten (10) notches in total. Each notch represents 1/10th of a revolution. There is also a small white dot on one of the ears of the knob:

You'll be using this white dot (and the ten notches) to measure the knob's clockwise rotation and thus, the ever-increasing depth of the cutter.

To complete the cuts for each slide rail, you need to turn the adjustment knob exactly 19 notches from your starting position, or 1.9 complete rotations.

#9: (Finally) cut the slide rails!

You're finally ready to cut! With the jig lubed up, the blade zeroed, and the starting position clearly marked, you can begin moving the cutting car forward on the frame. This will remove aluminum from the frame, carving out each slide rail:

It's recommended you complete 3 to 4 cutting passes before rotating the knob one notch. We also recommend frequently applying more lubricating oil to the jig and car. Keep the slide rail area free of aluminum debris by using canned air or a brush to clean the area in between cutting passes.

Tip: If you notice the cutter feeling wobbly or if the knob feels loose when turning it, re-tighten the set screw holding the cutter in place. They can get loose.

To ensure a nice smooth finish, make small adjustments (one-quarter of a notch) for the final few cutting passes and ensure plenty of oil is present.

Repeat steps 6 thru 9 for the opposite side of the frame.

Once you've completed the slide rails on both sides of the frame, you can move the frame and jig from the vise.

Take a break, come back, and get ready for the machining final step: Cutting the barrel seat.

#10: Prepare your work to cut the barrel seat

First, disassemble the frame from the jig by removing the M5 x .8 Allen-head screw and dowel pins. Take a moment to inspect the frame, and clean off any debris.

Re-secure the frame and jig by relocating the dowel pins and re-tightening the screw as shown below:

With the frame and jig reassembled, clamp the assembly vertically in your bench vise. To prevent marring the surfaces of the side plates for future builds, use some rags or towels between the vise jaws.

Next, grab the cutting car and relocate the handle and adjustment knob to the left side of the car:

#11: Zero the barrel seat blade, cut the seat

To begin cutting the barrel seat, position the car atop the frame and jig as shown below. Apply plenty of lubricating oil to all the contacted surfaces just like before:

BEFORE CUTTING, be sure to loosen the barrel seat cutting blade's set screw and zero the blade. Repeat steps 7 and 8 as described above.

Remember to mark the starting position of the blade relative to the white dot on the adjustment knob before making the first cut.

The barrel seat must be cut to a depth of 0.077", which requires 2.4 complete revolutions (24 notches) of the adjustment knob. Just as before, make smaller cuts for the final passes to achieve a smooth, polished finished.

Barrel Seat Cutting Tip

To ensure you don't cut the barrel seat too much, double-check the cutting blade's depth as you near the end. There are two ears on either side of the cutter:

If you see the ears on either side of the cutter removing material from the frame, STOP CUTTING. You've reached your final cutting depth.

Your 1911 Frame is Complete!

With the barrel seat cut, you can take a moment to celebrate. You're now the owner of a proper 1911 frame! With everything cut and drilled, you can begin the final assembly of your slide, barrel, and parts kit.

Summary

Cutting and drilling the 80% 1911 frame is the hardest part of this entire project. But with the right tools - and by closely following instructions - you can have your own home-built 1911 ready for the range in a single afternoon. Need help with your build, or have questions about completing your frame blank? Give us a call or email us. We build black rifles and handguns in our spare time, too!

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.