The Home Machinist

Get a grip on screwdrivers, and meet some unique (and useful) tools.

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In a recent column I wrote about screw-head forms: Phillips versus straight versus Torx, and I lauded the Torx for its ability to hold the screw in a horizontal position. Thats fine, but what if you prefer a more traditional form? What if you want the screw to stay attached to the driver regardless of its orientation?

I rummaged around in the toolbox and found four such drivers that will do just that. Actually, these are more correctly called screw-starters, though one style will do both functions. All of them have their advantages and disadvantages, but one is clearly superior.

Take a look at the photos that accompany this article. Go ahead, Ill wait…Good, you’re back. From the handles you can see that the red and green starters are from the same manufacturer; green is for #2 Phillips, and red is a quarter-inch straight blade. You can also see that while they hold the screw very well, they’re limited to a #8 screw; anything larger wont fit in the slot. They also have a lower limit of about #4; less than that and the head will fall through the slot. Counter-sunk screws will fit, but only within those ranges. They will, of course, also function as drivers, but that gripping mechanism is a bit large for confined spaces. Interesting, but not recommended.

The double-blade version of the screwdriver has been a favorite for many years. It works on straight slots and accommodates a wide range of screws. Note that the screw it is holding cannot be started with the green tool, because the head of the screw is too large to fit within the greens slot. I was able to use the double-blade on a special screw with a head that was three-quarters of an inch in diameter. The double-blade cant be used to tighten the screw, though, because you will twist its two blades out of alignment. Recommended, but only for straight-slot screws. Snap-on lists it for $11.25 under part number YA355.

This gem comes in eight variations from Snap-on. The one shown is GA199A and sells for $12.90. It is definitely something you should have in your toolbox.

The last one, small, is double-ended. One end works on straight-slot screws, and the other end accepts Phillips screws. It also covers a wide range of screw-head diameters and is not limited by the thread size. Its body is only about a quarter-inch in diameter, so it will work in confined spaces and its quite inexpensive. Use it for starting screws, but not for tightening them. Its equally useful in grabbing a screw that, if fully removed, would fall into an inaccessible hole. Just loosen the screw with a standard driver, cock the mechanism, push it against the screw to trigger the grip, and turn out the screw.

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Bob Fritz
KITPLANES readers will remember Bob Fritz (1947-2011) for his acclaimed Home Machinist series, but his accomplishments go well beyond that long-running feature. Following a stint in the U.S. Navy, Bob put his degree in mechanical engineering to use and was a tireless advocate for effective and consistent quality control. He brought that discipline to his work for KITPLANES. An avid diver and motorcyclist, Bob's love of flying was a surprise to no one.

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