How An “Improvement” To The Phillips Screw Made DIY Harder

The Screwy Secret That Almost Nobody Knows


Stolen from Pinterest

This past weekend I went to pick up a bookshelf from someone in the neighbourhood, and for the millionth time ran into a problem I’ve been aware of for ages and nobody else seems to be familiar with: Posidriv screws and Phillips screwdrivers. A few years ago we moved into an apartment where almost every screw I encountered seemed to be stripped! Some of them were so bad that I eventually had to bring in a professional to remove them, and he taught me to identify the different screw types…

A brief history

Once upon a time, there were Phillips screws (or “star”, to some of us laypeople) and Phillips screwdrivers, and everyone was happy. Then, in 1962, an ingenious patent was secured by the Phillips Screw Company and the American Screw Company: a subtle improvement to the famous Phillips screws. Officially called “Pozidriv”, which is short for “positive drive”, the new screw design had parallel flanks which enable an appropriate pozidrive screwdriver to apply more torque and also provides a sturdier grip. As an added bonus, Phillips and Pozidriv screws and screwdrivers look almost identical, and using one type’s screwdriver on the other is a sure-fire way to strip both screws and screwdrivers alike.

How To Identify Posidriv Screws

From the moment that you have reviewed these pictures, you will be privvy to “secret” information that until now has been enjoyed by only a select few:

Stolen from Wikipedia
Stolen from Wikipedia

As you can see, the difference is simple, subtle, and incredibly difficult to spot from any distance or any indirect angle or under less than ideal lighting.

Please share this information with anyone who will listen. Teach your children!



Adam Fisher / fisher king (@therightstuff)

Software developer and writer of words, currently producing a graphic novel adaptation of Shakespeare's Sonnets! See for details.