Fixture and Grasping Groove Instructions

[Harry Bonar]

Take a bar of aluminum (or steel) 7" long, .875" thick and about 1.200" high.
Put in mill verticle, level and on each side mill down .200, leaving the top of fixture .619" wide. Be sure each side is indenticle.
5.250" legnthwise on fixture (this will be the "front" of slide) just cut this whole end portion down to .619" wide. 5.750" from rear mill out a portion (this will be the front of slide area) to clear the plunger plug area of slide.
Now, coat both sides of fixture with layout dye, and at the front (where you milled out for plunger plug area for slide clearance) measure down from top of fixture 1.160" down and mark with scriber. Now, at the rear (where rear of slide will be) measure down from top of fixture 1.130" and mark it. Now take a straight-edge and connect the two lines with a scribed line.
Turn fixture over and line up this line level in mill, and mill portion off. This will take care of the .030 (approx) taper that Colt and most 1911 packages have. You can now clamp slide on fixture horizontally in the vise and grasp it all along the slide so it won't slip. Make sure all milling is 90 degrees!
Now, milling the grooves.
Coat the forward portion of slide with layout dye, both sides, and measure back from FRONT of slide 1.400, and scribe a line, both sides! Mount slide horizontally on fixture in vise and level both ways in vise and clamp. Watch the writing on slide - don't mill into these.
Set your head angle at 30 degrees so cutter is cutting TOWARDS front of slide with a sharp 3/8 mill in your R-8 and turn lip of cutter so you can see it come right up on the line. Touch down with mill, back out and go down for your cut .125. Cut your first serration (we are moving TOWARDS the front of slide)! The spacing is .070". Cut another serration, and another, and another; all spaced .070!
Remember, you are cutting towards the front of slide .070" at a time.
I usually get about 12 serrations on a full size Colt; you can suit yourself.
You may use a dial gauge, or set up a table from your milling wheel with graduations on it as I do, or just reset your dial gauge each time - DO NOT MISS A SERRATION!! Now, I hope I've not left anything out. On Springfields or others with angled serrations match them with the degree setting on your vise base. On Springfields this is 15 degrees! Remember to turn over slide - do not forget to change vise angle also on tapered serrations. On "Gold Cup" rectangular serrations use this fixture with a 3", carbide cutter, make a cut and FROM THERE space .100"! Use a horizontal mill. Depth is .125 for Gold Cup, or, you may vary this to suit. I'm going to post this now before I loose it and will make additions if I see something left out. Pictures of the set-up can be seen on my post with pictures! If any questions please post and I'll respond. Harry B.