I needed to make custom length bolts that had knobs like they sell at Rockler Woodworking. I wanted to be able to turn them by hand and not have to use a wrench to tighten them.
I needed 16 of them. It was going to cost over $40 -- BUT -- they don't carry them in the length that I need them -- 3 inches.
I decided to print them on a MakerBot Replicator 3D Printer for less than $0.30 each. I bought the bolts at Home Depot.
Step 1: Design in Inventor -- Then 3D Print!
I used Autodesk Inventor to design the part. I then saved the part to a .STL file (see attached) and printed them on the MakerBot.
This was printed using PLA Plastic. It took about 20 minutes to print each one.
You can use any length bolt that you want as long as it is a 1/4" x 20.
I made 16 of them at TechShop. I saved a lot of money and they work great!