How to Break in Your 1911 Frame and Slide with Polishing Compound

Posted by 80-Lower on Oct 22nd 2018

How to Break in Your 1911 Frame and Slide with Polishing Compound

Once you’ve finished your 1911 build, things may be… tight. There might be some grit, some grab, and a little too much friction in certain places – even if you took your time during machining and final assembly. Trigger pull weight may be a tad heavy, too – somewhere above 5 pounds. Today, we’re going to teach you how to break in your 1911 frame and slide with polishing compound!

#1: Work the Frame and Slide, Find the Rough Spots

Sometimes, simply machining the 80 percent 1911 frame and slide isn’t enough. Even when tolerances are generally in spec, there may be some raised or rough areas that require extra attention. Any spots requiring polishing will show wear lines and drag marks once you’ve assembled and operated the slide back and forth.

If you prefer a thorough job, machinist’s Dykem (or a permanent marker) works well as a metal stain. Coating the frame and slide with Dykem or marker and then assembling and working both will allow the dye to precisely and clearly highlight even minute imperfections for removal later.

#2: Remove Small Imperfections with Polishing Compound

Polishing compound is not to be confused with grittier lapping compound. Lapping compound should not be used for final fitment – it may remove too much metal elsewhere. Polishing compound is less abrasive and will remove small imperfections in the surfaces of your slide and frame while retaining the integrity of the surrounding metal.

Reassemble your frame and slide, dabbing a small amount of polishing compound atop any imperfections or sticking points. Simply operate the slide back and forth, working the polishing compound across the imperfection. Once a smooth, gliding motion is achieved, remove the compound and wipe the surfaces clean. Reassemble to test fitment and repeat the compound process as needed.

#3: Final Polishing and Break-In

Once reassembled, apply a final coat of Dykem or marker and test your fitment again. Even though no large or conspicuous imperfections remain apparent from staining, you may notice the slide and frame are still tight or unwilling to glide smoothly.

If this is the case, removal of more metal with polishing compound won’t suffice. Further compound polishing will only result in a looser fit with no glide. Final polishing for a perfect finish requires fine-grit emery cloth or crocus cloth.

These cloths are abrasive like sandpaper but as their abrasive surfaces wear, the underlying fibers and media begin to polish the worked metal surfaces with a finer grit, eventually resulting in a mirror finish – the finish you need so your homebuilt 1911 feels like it costs in the thousands.

Tips for Polishing Your 1911

Sometimes, imperfections may be present that cannot be attacked with soft polishing compound, nor can they be worked further with lapping compound. In this instance, you’ll need to invest in a mechanical, targeted method of polishing with sandpaper or media.

Because lapping compound is high-grit, you’ll want to start with high-grit paper. Using sandpaper or media that is more abrasive than lapping compound will only result in added imperfections and rough marks on your slide or frame. We recommend starting with 800-grit sandpaper and only sanding in one direction.

For a perfect finish, we strongly recommend using only aluminum polish on your frame rails. Steel polishing compound may be too abrasive for a mirror finish. We also strongly recommend against using powered buffing wheels or Dremel-affixed polishing tooling – these could result in removing too much metal from your aluminum frame.

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.