Custom 1911 Project: Part 5- milling the slide for low mount sights

Custom 1911 Project: Part 5- milling slide for low mount sights, presented by Rifleshooter.com and Brownells

This is the fifth installment of our Custom 1911 project- in this post we are going machine the slide to install low mount sights.

Our custom Remington R1 is outfitted with the following Wilson Combat parts:

A set of well fitted combat sights are a great addition to any 1911. Before they became common place on production guns in the late 90s, Novak Lo-Mount sights were the mark of distinction on a custom gun. While many off the shelf 1911s will now have Novak sight cuts, some still do not. I actually prefer to machine my own slides to ensure a perfect fit. On this pistol, I’ll be fitting a set of Wilson Combat #463T Combat Pyramid sights. These sights fit a standard Novak style sight cut.

Before we proceed, please read the following disclaimer:

Warning: The contents of Rifleshooter.com are produced for informational purposes only and should be performed by competent gunsmiths only. Rifleshooter.com and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.

Any modifications made to a firearm should be made by a licensed gunsmith. Failure to do so may void warranties and result in an unsafe firearm and may cause injury or death.

Modifications to a firearm may result in personal injury or death, cause the firearm to not function properly, or malfunction, and cause the firearm to become unsafe.

Unlike many basic 1911 style pistols with a staked front sight, the Remington R1 has a dovetailed front sight that is held in place with a set screw. The cut is generous, with light showing between the base of the front sight blade and the slide. To remove the sight I simply backed out the set screw and pushed the sight out with my finger. I actually would have preferred a staked sight so I could have machined the sight myself.

The rear sight is set in a dovetail and secured with a set screw. It reminds me of the rear sight on the USMC MEUSOC pistols back in the day (prior to the M45 and M45A1). To remove this sight, I backed out the set screw and used a nylon drift to move the sight from the left to right. These drifts work great and don’t cost a lot, Brownells sells them in a 3 pack for a few bucks.

All parts are stripped from the slide and it is placed on a set of parallels in the milling machine’s vise.

The first step is to machine the rear of the slide down to the bottom of the dovetail cut. I use a 3/8″ solid carbide four flute end mill for this.

To determine the centerline of the dovetail, I indicate off the rear of the slide with an edge finder. I used to use an electronic edge finder, but I found this Brown and Sharp version works well.

Rear sight dovetail cutters are expensive and fragile, a bad combination. I like to hog out material with an undersized carbide end mill prior to running the dovetail cutter. I always make this cut a few thousandths shallower than the final dovetail cut.

The location and depth of cut for the dovetail are critical. I started using this electronic depth finder to locate the cutter. Simply touch the bottom of the cutter to the tool and it lights up. The tool is now 2.000″ +/- .001″ from the indicated surface.

Low and slow! I run the cutter at a low RPM, with lots of oil at a glacial pace. No sense being a hero, I’ve broken and chipped these things in the past and they cost bucks!

One last step at the mill, the front sight cut needs to be trimmed on the mill.

The flattened area on the top of the slide around the dovetail won’t allow the sight to fit. A quick pass with a four flute end mill fixes this.

I take the time to make sure everything fits right. The sights or dovetail (most guys like modifying the sights because they cost less) can be opened slightly with a 60 degree file or stone. Since this gun will have a layer of Cerakote on it, I don’t want the sights to be too tight. This will only lead to scratches and a damaged finish during final assembly.