Custom 1911 Project: Part 7- machining ball cuts on a 1911 slide

Custom 1911 Project: Part 7- machining ball cuts on a 1911 slide, presented by and Brownells

This is the seventh installment of our Custom 1911 project- in this post we are going to machine ball cuts on a slide.

  1. Custom 1911 Project: Part 1- getting started
  2. Custom 1911 Project: Part 2-undercut trigger guard
  3. Custom 1911 Project: Part 3- fit and blend grip safety
  4. Custom 1911 Project: Part 4- Machining a chain link front strap
  5. Custom 1911 Project: Part 5- milling the slide for low mount sights
  6. Custom 1911 Project: Part 6- flat top and chain link top of slide
  7. Custom 1911 Project: Part 7- machining ball cuts on a 1911 slide

custom 1911 full right side of pistol

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

Machining ball cuts onto the front of a 1911 slide gives the finished pistol a more refined look.  Some claim that these cuts help holstering the pistol, but that doesn’t matter to me, I think they look cool.

I ordered the following tools from Brownells to use on this project:

For reference purposes, a schematic of a 1911 pistol can be found here.

Before we proceed, please read the following disclaimer:

Warning:  The contents of are produced for informational purposes only and should be performed by competent gunsmiths only. 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.


1911 ball cut slide beforeIf you take a look at the cuts machined on the bottom front of most 1911 pistols, they have a familiar look.  Notice they sweep down and stop short of the dust cover.  Many custom pistol smiths will modify these surfaces with a ball end mill for a more refined look.

1911 ball cut slide determine radius

A radius gauge is used to determine what sized ball end mill is needed.  The 1/4″ radius gauge matches up, so a 1/2″ ball nosed end mill will work.

1911 ball cut slide measure distance to dust cover

Next, the assembled pistol is placed in a vise and a depth micrometer is used to measure the distance from the front of the side to front edge of the dust cover.  This will allow me to make sure the cut ends at precisely the right location.

1911 ball cut slide parallel to bottom 2

Set up of the slide in the milling machine is absolutely critical.  As was discussed in the previous parts of this series, the slide on a 1911 is taller in the rear than the front.  This means the bottom edge and top are NOT parallel.  If you set up the milling operation off of the top of the slide, the ball cuts will look like they have a taper- see above.  This is because the ball cut gets progressively deeper as the cut moves towards the rear of the slide.  I machined the cut on the slide above as a demonstration of this for a friend, if you like the way this looks (different strokes for different folks), have at it.  If you don’t, make sure you indicate off the bottom of the slide during your set up.

slide parallel to bottom

To set up the slide to the balls cuts will be parallel to the bottom of the slide, I start with a cross-test level to make my initial set up.  Next, I check the bottom of the slide with a drop indicator to make fine adjustments.

1911 ball cut slide recut

I locate the edges of the slide and determine the center line of the slide.  I will zero my digital readout (DRO) to this.

running ball mill 1911 ball cut slide

Then I begin running the ball end mill.

making 1911 ball cut slide

I take light cuts and ensure I stop at the calculated distance.


When the slide comes off the mill it looks pretty good, but a little polishing will go a long way.

1911 ball cut slide right side polish

Polishing with abrasive cloth against a wooden sanding stick helps blend the surfaces.

polish 1911 ball cut slide

Things are starting to look good!  A little more work and it is ready for Cerakote.

custom 1911 ball cut slide

The ball cuts look good, don’t they?  Note how the ball cut ends where the dust cover on the frame begins!  How’s that for custom?

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