Nonny wrote:
Harbor Freight sells one of those "tools you put in your toolbox and
only get out rarely when all else has failed." It's called an impact
screwdriver. They've been around forever, and the one I just got cost
less than what I paid for one 55 years ago.

What they are is a very heavy solid steel handle with a coarse pitched
screw thread inside, so to speak. Inside the threaded area is a mated
shaft with reversing toggle, and on the end of the shaft is a hex holder
for various screwdriver bits. The tool is a heavy duty version of the
Yankee drill we all remember. They have a socket wrench-type of shaft
and apparently can also be used on bolts, but I've never tried that,
since I have a pneumatic wrench that works well. Their best application
is in loosening frozen screws, where an inward application of force and
twisting motion is needed.

To use the impact screwdriver, you place the appropriate bit in the
holder and hold the screwdriver firmly while tapping on it with a
hammer. The impact forces the bit into the screw, helping to prevent
the head from stripping, while the coarse threads make the bit twist
just a tad. Usually, that's enough to break loose a frozen screw if
you're lucky, and you then follow up with a regular screwdriver to
finish the job.

The first one I had I bought as a teen to work on my motorcycle's engine
and had it for around 40 years. During that 40 years, I probably had to
use it a dozen times at the most. However, each and every time it saved
the day for me. The one Harbor Freight sells appears to be a clone of
my old one and I suspect it'll serve the purpose longer than I'll ever
need.

Nonny


I agree with most of this thread except the above "hold the screwdriver
firmly while tapping on it with a hammer".

Tapping it? I hit it with a 2# sledge like notbob mentioned.