Looking for jig instructions? Click here for the how-to guide.
Completing your 80% 1911 frame is incredibly easy. In fact, it's probably easier than fabricating an 80% lower for an AR-15. But getting the job done - and winding up with a 1911 frame that'll take a barrel and parts kit - means having the right tools. All the tools required are simple, affordable, and require no gunsmithing knowledge.
Hand drill or Drill Press
Drilling the pin holes in the 1911's frame requires a hand-operated electric drill or, ideally, a drill press.
5" Tabletop Vise
A tabletop vise is required to accurately cut and drill the 80% frame. With the frame secured inside the jig, you'll clamp the jig down so it remains stable while you fabricate.
You do not need a large cross-slide vise as illustrated in the instructional photo above. You will need a vise wide enough to accommodate the width of the left and right jig plates. We also strongly recommend bolting or clamping the vise to your table or workstation. The cast iron vise we sell (pictured above) has various slots for bolting it down. It's affordable and easy to use, too.
The Stealth Arms Jig makes cutting the frame pretty easy. But to ensure a perfect fit for the slide and barrel, you'll need a pair of digital calipers, or a micrometer like the one above. This micrometer measures down to thousandths of an inch, ensuring the required depth of the frame rails - 0.061", to be precise - is made with the jig's provided cutters. Just as important, you'll need to ensure the depth of the seat is exactly 0.077". If you accidental remove too much material, your frame won't work. It's best to measure as you cut with a micrometer instead.
Lapping Compound & Rubber Mallet
As you approach the final cutting depths on your new frame, you should find that all the parts required for assembly - most of all, the slide - fit quite well. Except in reality, minor differences in measurements between slides and frames means there could likely be some fine-tuning, of sorts. It's not uncommon for your new slide to have a tight fit when you install it in the frame.
This is a simple fix: grab some fine-grit lapping round (we recommend Wheeler's 600-grit) and install the slide - if it's a very tight fit, use a rubber mallet to help seat it - and work the slide back and forth with the lapping compound liberally applied inside the frame rails (grooves for the slide). This will lightly sand and polish the frame, giving the slide enough room to operate smoothly and without binding.
Trigger Track or Ceramic File Stone
The 80% 1911 frame is CNC-machined, with incredibly tight tolerances. The area wherein the trigger installs (besides the pin holes) is already machined for installation of the trigger itself. But like we mentioned with slides, trigger assemblies may have slightly different tolerances that could cause the trigger to feel tight, or gritty.
If you install your trigger and find this is the case, it can be remedied with a trigger track stone. Trigger stones are really just rebranded ceramic filing stones, typically used to clean up the edges on carbide bits and knife edges. This 90-degree squared stone will help polish and deburr the trigger bow ways, which could cause a tight fit with any trigger.
320-Grit Sandpaper or Lug Iron
Although not related to the frame itself, you may find your chosen slide and barrel provide a tight lock-up or poor fit once seated in the frame. This is usually because the barrel lugs cut into the inside of the slide are machined too high. A simple sanding job (removing only a few thousandth's of an inch, at most) will typically remedy the issue. We recommend silicon carbide sandpaper, which works best on steel and can be used in tandem with gun oil to produce a clean, smooth finish. A strip of 320-grit works best. A tool called a lug iron can be used, but it's typically not necessary unless you're building quite a few 1911's.
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.