Precision screwdrivers that are geared DOWN?

Hello folks! My friend is looking for screwdrivers that are geared down, so that one rotation of the handle might mean a 1/4 rotation of the tip. There are a few screwdrivers geared the other way, for more speed, but this would be the opposite.

Precision screwdrivers would be ideal, but any size would do.

Anybody have any ideas?

There is a patent for this exact thing but I’ve never seen one in the flesh or even a picture of one outside of the patent drawing.

The closest thing that I have seen in person are reduction gearboxes that are really meant to be used with a drill. You could use one with a bit handle instead. It would be not be a very elegant solution but it would work. For example:

There is also an older metal design called the Supreme Versamatic but I don’t think those use hex bits.

Thank you sir! I appreciate it!

That screwdriver design is a little puzzling. The transmission is at the front, and exposed to dirt and debris. I’d have put it inside the handle, to protect the gears.

It’s a strange drawing for certain! I wonder if the drawing isn’t meant to be an example rather than a definitive design, even if you stuck the gears at the front why would you leave them exposed to dirt and debris instead of enclosing the design? Or make the whole assembly slimmer by using a planetary arrangement instead?

Anyway, I hope someone has seen something like this out there because if well implemented it would be a useful tool–not just for difficult to drive screws, but also for making precise adjustments.

I was thinking about a planetary gear transmission. Would it be slimmer? It would be like the one in the patent drawings, but with three planetary gears instead of one, plus an outer ring gear. Wouldn’t that be wider?

The skinniest transmission I can think of is a bevel gear fixed to the handle, then two bevel gears engaged with it, and the shaft driven by the axle between those two gears.

I think you could make a planetary arrangement slimmer than the patent drawing because you are dividing the load up among multiple planet gears. That could let you use smaller gears to achieve the same torque rating.