Building The Steven's Favorite

[TomG]

I finished machining the base tonight. There is a fair amount of shape to it, such as radiused corners and surfaces typical to firearms, and that will be done by hand, but all the machining is complete.



This is the radius on the underside of the base that matches the radius on the tang of the receiver (tang sight, get it?). It was accomplished by mounting a fly cutter in the boring head to achieve the 1.500" radius.




Here the basic shape is roughed out and the mounting holes added. The top surface will ultimately have a convex curve to it that will be machined with a 3/4" ball end mill on the rotary table.




Here, the base is mounted to a fixture on the rotary table to generate the convex top surface using the 3/4" ball end mill. The fixture is just a piece of 3 1/4" aluminum round with a slot the width of the base and a couple of tapped holes. I figured the slot was good insurance to take some of the load off the 4-40 mounting screws since some of the head on them would be milled off.




The base was then mounted to an angle plate on the rotary table to machine the .200" radius on the center section. Both the table and the part were located using gauge pins in the spindle just as with the frame.




Here it is as machined. To finish it up, all surfaces will be polished and many of the corners rounded. Since everything is O1, it should polish up nicely. Unfortunately, on a part like this, that will all need to be done by hand. It's the extra work that goes into shaping parts like this that gives a firearm it's character.




Almost done. I still need to make the windage thumbnut and assemble the detent mechanism. I see the parts showed up today, some 3/32" compression springs and balls, and the 1-72 threaded rod for the windage adjustment. That will be tomorrow evenings project.