Here you can see the round pockets where I'll be placing the stainless steel. These round pockets are 1/2" diameter and the slots are 1/8" wide X 1 1/2" long.
 

Here is the stainless steel and brass that I'll be using. Both of these materials were leftover from a previous project.
 

I'm going to use my 5-C collet holder to machine the other end of the stainless pieces. The main reason for this is because I don't have a work stop on my lathe and with parts this short, it's just easier to hold them in a collet.
 

What you see below is a collet stop that I made many many years ago. This only works with 5-C collets and is adjustable. And I also made some threaded pieces of various sizes to accommodate different diameter work pieces. The one that is threaded in the collet holder is 1/2" diameter, which is what I need for my project.
 

The large thread on my collet stop threads into the back of the collet (arrows). Then you can adjust the long threaded piece in or out of the collet to whatever depth you need. Once you have the depth set, you tighten the jam nut and you're ready to machine some parts.
 

Here is what the business end of the set-up looks like. Now I can machine each part to the exact same length. But I have to remove the hex holder each time I do that, which is no big deal for this amount of parts.