Mach4
Member
Some of you will recall my write up on a modified way to make 50 cal pens using 3D printed inserts and ball bullets - https://www.penturners.org/threads/50cal-bmg-pens.173120/ Over half the bullets I procured were armor piercing and were so hard it was impossible to turn or drill. In fact, I broke a carbide turning tool just trying to make a mark on one. I've spent a good deal of time trying to figure out a way to use those bullets in pens so they don't go to waste. I love the historical significance of the casings and bullets and making a pen out of them makes a great keepsake. This write up describes my first prototype using the flip pen as a model.
As I mentioned, the bullets cannot be machined so I needed to find a way to incorporate them into a pen as is. The strategy I settled on was based on the flip pen model. I turned off the bottom 3/8th inch or so of the copper jacket to expose the hardened steel core. I then made a matching recess in a 1/2" brass rod. It turned out that a "stepless step drill" has almost the perfect angle so I ground off the bottom of the drill to match the diameter of the steel core. I was then able to epoxy the bullet to the brass.
The flip pen kit is able to use a full size refill because they drill the "bullet" to gain enough room. I don't have this option so I researched refills and discovered a really short refill that is used in the Shaffer Ion pens. Alas, even this short refill was not short enough and needed to be shortened 1/4" inch. The barrel of the pen is threaded so that it can be attached to the segment with the bullet attached. This pen uses a very plain design with a straight body and a gentle taper to the tip. I anticipate using carbide tools in the future to manually turn more intricate and interesting designs.
Ssdfd
As I mentioned, the bullets cannot be machined so I needed to find a way to incorporate them into a pen as is. The strategy I settled on was based on the flip pen model. I turned off the bottom 3/8th inch or so of the copper jacket to expose the hardened steel core. I then made a matching recess in a 1/2" brass rod. It turned out that a "stepless step drill" has almost the perfect angle so I ground off the bottom of the drill to match the diameter of the steel core. I was then able to epoxy the bullet to the brass.
The flip pen kit is able to use a full size refill because they drill the "bullet" to gain enough room. I don't have this option so I researched refills and discovered a really short refill that is used in the Shaffer Ion pens. Alas, even this short refill was not short enough and needed to be shortened 1/4" inch. The barrel of the pen is threaded so that it can be attached to the segment with the bullet attached. This pen uses a very plain design with a straight body and a gentle taper to the tip. I anticipate using carbide tools in the future to manually turn more intricate and interesting designs.
Ssdfd