![]() ![]() ![]() By the 15th century, metal screws appeared, but being hand-made they were not very regular and were only popular in limited applications. Threaded wood for things like olive presses started showing up about 2,000 years ago or so. The screwdriver isn’t self-centering either, so applying force off-axis is common and contributes to the problem. It is very hard to apply lots of torque to a slotted screw drive without camming it out or snapping the head off the screw. The disadvantages, though, are significant. I’ve heard people claim that it also is a feature that the screwdriver can pry things like paint can lids, but that’s a feature of the tool, not the screw drive. The only advantages I know of for the user is that you can easily clean a slotted drive and - possibly - use field expedient items like butter knives and quarters to turn the screw. A hacksaw is sufficient for the job and there are other ways to get there, too. The reason slotted heads - technically known as the drive - are so common is probably because they are very easy to make. While it is true that slotted heads have been around for ages, better systems are both common and have been around for at least a century. The only thing that I find remarkable about that is that it took so long. I’ve noticed, lately, that slotted screw heads are all but gone on new equipment. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |