“The Smallest Screw”

All jokes and puns aside these really are some of the smallest parts I have ever been asked to work with. Such a small screw I thought it worth sharing about.

Note: most of the details about what and how this minuscule screw is used are protected under the oh so common NDA.

What I can say: it is about 0.5 mm in diameter on the major and 1 mm at the head.

Our customer and designer / fabricator of “The Smallest Screw”, Mr. Marcello Dagata of DP Machining, Inc. out of La Verne, CA asked if we would be able to roughen up the surface for some kind of adhesion application. Sales 101: always say yes, so, I asked for a sample. When we received them, 10 in a small zip top bag each screw roughly the size of the period at the end of this sentence, I passed them around in a meeting with my engineering team. One engineer asked, “is this a joke?” and it was followed by a chain of explicit remarks only suitable for locker rooms and shop floors.

Needless to say, we all had the same first question, “How are we supposed to hold those things?”

This is what we came up with:

1. How do we hold it? We needed a fixture. Settled on a bamboo chopstick with shallow holes drilled 12 micron smaller than the major diameter of the screw head.
2. How do we handle them? We made an insertion tool to load them in the fixture. Then we used a good pair of plastic tweezer to pull them free from the fixture after processing.

The actual time to blast the parts we minimal 15-20 seconds. Conversely it took around 15 minutes to load the fixture.