1911 Front sight Installation

1911 Front sight installation

We decided to upgrade the sights on our Colt Series 80 Officer’s ACP.  In addition to adding a Heine Ledge rear sight, we needed to replace the factory front sight with a new tritium model. The new sight will require a dovetail cut, unlike the staked version from the factory.

Brownells provided the following tools and parts:

The following documents the process we used to install our sights and is presented for information purposes only.

The factory front sight of our Colt Series 80 Officer's ACP.

The factory front sight of our Colt Series 80 Officer’s ACP.  The slide is stripped prior to machining.

In addition to a milling machine, we will use the following tools to install sights.  Dovetail files (bottom), solid carbide endmills (lower center left), carbide dovetail cutters (upper center left), calibers (top), edge finder (upper center right) and a brass and plastic drift (lower center right).

In addition to a milling machine, we will use the following tools to install sights. Dovetail files (bottom), solid carbide end mills (lower center left), carbide dovetail cutters (upper center left), calipers (top), edge finder (upper center right) and both a brass and plastic drift (lower center right).

The factory front sight is secured with with a square tenon peened into place.  You can hit the bottom of the tenon from inside the slide, or, for a less refined removal, grasp the sight in a vise and pull it loose.

The factory front sight is secured with a square tenon that’s peened into place. You can hit the bottom of the tenon from inside the slide, or for a far less refined removal, grasp the sight in a vise and pull it loose.  This method lacks panache but gets the job done.

In order to mill the front sight we begin by securing the slide in the vice of our milling machine.  An electronic edge finder is used to located the front end of the slide.  Since our edge finder is .200" in diameter, we calculate a .100" offset into our measurements.  Note: The recess shown in the slide secures the sides of the front sight, a square hole in the bottom of the recess accommodates the tenon in the factory front sight.

In order to mill for the front sight, we begin by securing the slide in the vise of our milling machine. An electronic edge finder is used to located the front end of the slide. Since our edge finder is .200″ in diameter, we calculate a .100″ offset into our measurements. Note: The recess shown in the slide secures the sides of the factory front sight and a square hole in the bottom of the recess accommodates the tenon.

A .300" x 60 degree cutter is used to cut the front sight dovetail.  The centerline of the new sight cut is .252" from the front edge of the slide.  The depth of cut is the distance from the bottom of the front sight to the bottom of the dovetail less .001".  The front is  is approximately .304" with a .002" taper.

A .300″ x 60 degree cutter is used to cut the front sight dovetail. The center line of the new sight cut is .252″ from the front edge of the slide. The depth of cut is the distance from the bottom of the front sight to the bottom of the dovetail less .001″. The front is .304″ wide with a .002″ taper. Note: In the past we would sometimes make a rough cut using a small diameter end mill to prevent cutter damage and wear. Some installers, still make this initial cut.

The front sight dovetail is fine tuned with a 60 degree safe edge file.  The sight is drifted in with a brass punch from right to left.  Note: the sight has an arrow on the bottom indicating which way it is tapered.  On final installation, loctite can be used in the slot to add in a secure installation.

The front sight dovetail is fine tuned with a 60 degree safe edge file. The sight is drifted in with a brass punch from right to left. Note: the sight has an arrow on the bottom indicating which way it is tapered. On final installation, Loctite can be used in the slot to aid in a secure installation.