Intro: Make a Manual Power Screwdriver
This is going to be quick and dirty, besides there is little to say. The pictures tell the story, the bigger parts were picked up from a flea market along with some of the smaller parts. The new parts came from Lowe's Home Store.
If you want more power than a conventional screwdriver can give, but don't want an electrical powered one, you have a few options.
The first picture shows some of your choices.
At the bottom is a sliding t-handle with a 1/4" square to 1/4" hex adapter. The adapter is the important bit, it adapts a male square drive to a male hex drive.
Next up is a 1/4" speed handle modified with the addition of a wood workers crayon holder over the original handle. Not necessary and adds bulk and comfort. You could also use a 3/8" or 1/2" drive with an adapter to 1/4". But they are heavier and I didn't want the extra weight. Cautious with this one, a child can twist off the head of a screw.
The third driver is hard to find. It is an old child's brace drill, lightweight and will hold a hex driver directly.
Last and far for least is the more common ratcheting brace drill. It probably weights as much as everything else in the picture put together. It is rugged and will let you apply enough torque to twist off any screw head.
Also in the picture are some nut drivers, three of which can be used as extensions. If you look close you can see which ones can be used. Also a collection of bits and adapters that can be used.
The second picture shows one of the nut drivers from the first picture being used as an extension on the t-handle. It could also be used on the speed handle.
Total for everything is about in the first picture is about $50. $15 for the big brace, another $15 spent at Lowe's, $5 for the small brace(actually for two of them), $3 for the carded adapters in the middle, and about a $1 apiece for the rest. For under $5 you could have a high torque screwdriver that never needs batteries.