FITTING A TRIGGER SO THE SIDES OF THE SHOE DON'T GET SCUFFED IN NORMAL USE.
As good a finish as DLC is, it can still be scuffed through from repeated rubbing with the shoe tracks in your frame. Here is a PRO tip to instruct you in creating very small pads on the hidden sides of your trigger to keep the exposed flats of the trigger from touching the inside of the frame.
First we need to prep the inside of the trigger shoe track in the frame. Trigger shoe tracks in 1911 frames are finished by either broaching or single point shaping machines and both of them leave pretty rough surfaces. File, sand, stone the inside flats in the frame, where the trigger shoe lives. I use an 8" fine mill file with one edge sanded smooth and the nose sanded into a smooth radius. There’s no need for extensive metal removal and they do not need to be sanded out to a slick surface, just make it free from burrs and severe tool marks. Be sure you do a good job cleaning up the corners of the track and also filing a light chamfer on the trigger shoe itself on the top and bottom outside corners. I always wrap the rounded tip of my 8" file with masking tape as well as the inside of the trigger guard, so I lessen the chance that I leave a scratch inside of the trigger guard.
Make a swaging tool by re-purposing an old broken 1/16" punch, grinding it back until you create a chisel nose about 1/8" wide with narrow flat tip; not sharpened at all. You will also need a fine cut file and a wire brush to clean the teeth of the file. Mine is a 6” long mill fine cut file with a handle.
Now the delicate part: Hold your trigger in a padded vise, stirrup up and the back face of the trigger shoe slightly above the vise jaws. Use the swaging tool you just made and a light weight hammer to raise two welts of aluminum on JUST ONE side of the trigger. Strike straight in, parallel to the trigger box, from the rear edge of the shoe to make it swell out slightly on the side. Create one welt at the top of the shoe and one at the bottom. They only need to be .010" - .015" tall. DO NOT raise welts on both sides at once, or you will have a much harder time fitting the trigger!
Install the trigger in the frame. If it won't go into the shoe track, remove the trigger and put a layer of scotch tape on the side of the trigger shoe where you raised the welts, leaving only the welts exposed. Also put a strip or two of tape on the face of the file, lengthwise covering all but the outer ¼” of the teeth. Holding the shoe in a padded vise, use the taped up fine cut file and take 1-2 strokes from the welts being careful to keep the file level and not cut into the tape. Obviously, if your file touches the tape, replace it. If you scratch the shoe with your file, it will look awful. Let me say it again, you do not want to scratch the trigger, or you’ll have to have it refinished.
Remove the tape and reinstall the trigger and see if it goes in. You may want to color the welts that you are fitting, so you can see contact from the frame easier. Repeat until it does go in freely and each welt still stands proud of the side of the shoe. Then repeat the process on the other side of the shoe. Your goal is to have two raised welts on each side of the shoe, top and bottom which are hidden by the frame when the trigger is installed. They will take up the width of the shoe track and keep your exposed portion of the shoe from rubbing the frame.
One thing to remember concerning trigger shoe rubbing, is if you are running a trigger that is too long for you, you will have a lot more likelihood of rubbing off the side of the trigger than if you get correct length trigger for your hand size, so your trigger finger pulls straight to the rear.