I used easy to find materials
- - aluminum pop can.
- - Hexagonal keys (different size, it depends from the used scale).
- - A hammer.
- - Wood chock.
- - A small piece of plywood or something similar, but not very thick.
- - A polymeric clay (I used FIMO brand, but I know in other country it is called also sculpt clay)
- - An exacto knife.
Make some holes in little tin can aluminum sheet using any of the hexagonal key size you need. Place the tin can on the wood chock and hit the hex key with your hammer. Once you have made the holes, use the one with the best hex hole.
Make a central hole in the little scrap piece of wood, and glue/fix the aluminum sheet over it (make sure the two holes coincide).
Now the hard part. Put a small amount of polymeric clay (FIMO or whatever brand) over the hexagonal hole and press it.
Once the thread is the length and consistancy you need, it is time to bake the clay. Refer to the instructions on your particular brand for time and temperature. For mine it took about half an hour to harden it.
You are ready to slice it and get how many bolts you need.
The final result. Not too bad!!
You can make and handy pressing tool using a syringe and some clamps. But this is all another story. Use your imagination anyway.
Hope this tutorial helps to make a better looking diorama.