Splain to me Lucy about clutch head screwdrivers ?

[EVILDR235]

Shall be talk about Reed and Prince screwdrivers or JIS screwdrivers. Maybe we need a screwdriver forum ?

EvilDr235

[d42jeep]

Here are some of the more common style of clutch head drivers. The upper Xcelite has a reversible shaft. Thanks for starting this thread back then.
-Don

[skipskip]

this style was popular for carmakers in the early 50's.

not sure why and they faded out by the mid fifties.

[Ken W.]

If you ever go into a Thruway rest stop look at the bathroom toilet stalls. Most have the clutch style fasteners.

[EVILDR235]

GM was the auto maker who used clutch head screwdrivers. I guess they thought it would keep car / truck owners from working on their own vehicles. A person could use a regular slotted screwdriver on clutch head screws. I must own 20 clutch head screwdrivers and not a single screw that they fit. I was real sick 8 years ago and sold my 56 Chevy sedan that I had owned for 34 years and all the related parts.

EvilDr235

[J.A.F.E.]

I think the clutch heads were just an experiment by GM in seeking an alternative to the slotted screw. Post war was when lots of power equipment was starting to be used to assemble things and a slotted screw is not well suited to being power driven. Philips invented the Phillips screw form for use with automated drivers in the  late 40's - the original patents expired about 65 or 66 and at that time a utility patent was 17 years.

I believe the use of clutch heads by GM was in part because a flat driver could be used in place of the special driver. The clutch head was designed to be power driven and to be compatible with a flat bladed screwdriver. Presumably the thinking was the factory could drive the screws with power equipment and mechanics/owners could use flat drivers they already owned. The type G was patented in the early 30's and is the form GM used by Joseph F Fieg to United Screw and Bolt Corp #1894034A on 1/10/33. Type A came along later (around 1940) under (I think) patent 2142185 also by Fieg to United Screw. A type A driver is designed to work with a type G screw as well as a type A screw. Feig described the type A as an improvement to the type G.

To me the question is not why GM used the clutch heads but why stopped with a folowup of why they migrated to the Phillips screw form. Phillips is designed to cam out when over torqued clutch head will not. Hard to find a lot of info on clutch heads though. The only thing I can think of is Phillips lends itself to a lot of low profile screw head designs like pan heads better than clutch.

In Canada Robertson is very popular as it here in the states with a lot of wood workers. For the same reasons Robertson is better than Phillips I believe clutch is also better than Phillips.

[EVILDR235]

What J.A.F.E. said about the factory being able to use power tools to drive clutch head screws and the home owner can still remove or install them with a regular screwdriver makes sense.

EvilDr235