This tutorial demonstrates how to fabricate hex bolts using a lathe, pin vise, and sandpaper. One does not need a mill to make the hex head, but a pin vise with a hex head is needed. I used this technique to make 1/12 scale bolt heads. The hex heads are probably not as accurate as milling them, but this saves a lot of machining time, and if you dont have a mill, its a way around that problem.
I will not go into the machining details, as anyone with a lathe should be able to pick up the tutorial at the beginning. That being said:
Turn this shaped part on the lathe. I used a cut-off tool for the cutting operations. The large diameter section should be about one-half as wide as the diameter to have the right proportions. You may want to experiment with this.
You need a pin vise with a hex head, as the hex will be the index for sanding the flats in the brass part. My vise has a swiveling head, so I had to tape it to keep it from turning. Level up the pin vise using blocks. I use sand paper of about 400 grit.
This shot shows the brass in the pin vise and resting on the sandpaper. Brass residue can be seen on the sandpaper from previous use. When the sandpaper gets clogged with brass, cut off the clogged part with scissors. Mount the brass in the pin vise solidly, as you dont want it to come out before you are completely done.
Here's another shot of the setup. When you sand the brass you will be moving the pin vise parallel to the block and sandpaper. You must let the hex head on the pin vise handle rest on the table while sanding. It may take a little practice.
Sand the brass a few strokes, then turn the pin vise until it is resting on the next flat. This is how you are using the pin vise head to index the brass part around. Continue this procedure turning the pin vise a total of six times. Use about the same number of strokes on each side. Its best to sand on all six sides before looking at the results. If more sanding is needed to make a proper looking hex shape, go another six turns of the pin vise.
This technique is relatively quick and gives decent results. I use a black wash on the bolts to bring out the detail, giving the illusion that the bolt is mounted on a stud. I have used this technique to make simple hex headed bolts and many other fittings that have a hex section. Hope this helps you scratchbuilders out there!