Monday, February 29, 2016

Fancy screwdrivers -- the scoop

I wrote last week about opening up the top section of my Bernina with what I flippantly called a "fancy screwdriver" and various commentators corrected to "Torx screwdriver," "hex key" or "Allen wrench."  I was moved to do some research and in case you're a hardware nut, here's the scoop.

The Allen socket aka hex socket was patented in 1910 but it is just one of many, many, many variants in screw/screwdriver shape that are designed to improve torque, reduce damage to the screw by reducing slippage, and allow access in tight spaces.  Courtesy of Wikipedia, here are a bunch of other designs:

The closest thing on this chart to the Bernina screw is the Torx, but maybe just a tad off.  The cross-section of the Bernina wrench is a perfect Star of David, with the lines between every other point drawn ruler-straight instead of dipping down a bit as in the Torx diagram.  Maybe it's some fancy European screw that didn't make it onto the Wikipedia schematic.

I guess I don't really care.  But don't run out and buy an Allen wrench if you want to open up your Bernina.


  1. Inspiration for 'signs and symbols'?!

  2. I always learn one new item every time I'm browsing the net and blogs! Thanks for the education!

  3. Glad you followed up! This type of minutia fascinates me, although in the bigger picture my quest for information that leads to lesser known facts may be more entertaining than earth shattering. IMO it's never a waste of time to learn something and to get nomenclature right. As you say - it matters what you call it if you're going out to get one. Thanks for posting that chart. I recognized quite a few of them, some that have always puzzled me as to why someone came up with them.