North Bros. #233H Driver

This North Bros. #233H Yankee Handyman screwdriver was the first tool I cleaned up from the items found at an estate sale a few weeks ago.  This post shows some inner workings and describes what was done to clean it up.

It's a small driver, about 10" long fully extended

In the center area, there is a switch that changes the spin direction of the bit.  With the switch forward, a push spins the bit clockwise to tighten a screw.  Center locks the push.  With the switch at rear, a push drives a bit counter-clockwise.

Center position  - push and rotation are locked out

Yankee Handyman

The heel end unscrews to get at the spring mechanism that returns the screwdriver to extended position after each push.  Many Yankee screwdrivers are found with these springs removed.  I read somewhere (a few years ago, so trust my memory or not) that users felt the spring-back unnecessary or possibly a safety issue.

End cap removed.  When installed, the cap surrounds the thin metal handle.

Unscrewing the spring cover allows the spring to come out

I'm pretty sure that's a wooden plug at the end of the spring - nice!

Looks like the handle is just sheet metal wrapped into a cone shape.
Or maybe it was damaged and was originally an intact cone.

This driver had tape wrapped around the handle.  I thought about taking the tape off to see what was underneath, but decided against it.  No doubt the tape was not original, but something had to keep the user safe from the edges of the wrapped metal handle.  Maybe if I had some extra bicycle handlebar tape or hockey-stick tape I'd replace it.

The center shaft has a thin tubular brass (or bronze or copper) piece surrounding it.
I couldn't remove it, but that may be what holds the handle on.
It was fit over the shaft like a slit-tube spring.

The inner works near the switch were interesting.  The parts in the following pics are pretty dirty.  All were cleaned up and oiled where necessary before reassembly.

Unscrew this nut from the end of the cylinder

It is free to slide up the shaft

After playing around, out popped this brass fitting that engages the threaded shaft.
Note the teeth are on the left end of this fitting.

Pressing the switch allows the cylinder to move forward, revealing the innards

The switch comes right off - it has a leaf spring on its underside.
The leaf spring presses on one of two funny-shaped plates (see below), depending on switch position.

Then there are these two interestingly shaped plates (one is removed).
They each engage a brass fitting, though not at the same time - it depends on the switch position.

Dental tool points to those two shaped plates.
Only one brass fitting is shown - the other slid to the right on the shaft
(it's hidden by the cylinder).

I spent some time cleaning up all these small pieces and getting rid of the gunk built up over the years. Dental tools, tooth brush, brass wire brush were all used.  After reassembling, there was some problem with the forward/reverse settings not fully engaging.  The driver would work perfectly first thrust, then lock.  I found that by holding the switch down while pushing, it worked fine.  So I took it apart again and found that by bending the leaf spring (on the underside of the switch) a little, the problem was solved.  It just needed to put a little more pressure on the engagement plates.

One last thing.  When putting it back together, a small piece fell out the opposite side from the switch and plates.

Hmmm, what does it do?

OK, that's where it goes (in that slot) and stays in place when the cylinder is replaced.
Its function (I believe) is to keep space between the two brass fittings.

After oiling the moving and sliding parts, the screwdriver works perfectly, probably as good as new.  One thing odd about this one, though.  The other push drivers that I've seen all have a locking mechanism that holds the shaft within the driver.  This one has no such mechanism, so the spiral shaft is always visible and subject to dust and crud.  So I cut a plastic straw to the length of the exposed shaft and then slit the straw lengthwise.  I'm using the straw as a cover to keep the shaft safe from dust when not in use.

Plastic straws have many handy uses

And finally, here's a shot of it all cleaned up, hanging out with some bits.

The chuck bit is really handy - it'll allow the use of any 1/4/" hex driver bit

These push drivers are great tools.  For the work I do, the longer ones seem to be more useful.  But this one will be a nice addition to the shop for when smaller work is done.