There were a couple of answers to my query:

The answer which said it screws onto a 1/4" drill shaft, and is used as a screwd
river, makes sense. But the one which said it was reversible by holding one half
 or the other does not. By hand holding the front half of the large cylinder, th
e speed of the output shaft is reduced, and the ratio is 14:1. The same thing ap
plies when the direction is reversed on the input shaft. The rear half turns wit
h the input shaft.

It seems that this is a 1957 product, and I wasn't aware that drills were revers
ible back then, but then there is a lot of stuff I don't remember anymore. I sup
pose they were reversible, but my memory is not.

I assume from the description I read on this tool that the 1/4" square drive tha
t it has on it was an option back then.

I am aware of the tapping device you mentioned, but this is not one of those.

On Jul 12, 2011, at 6:41 PM, Peter Huisman wrote:

> On 12/07/2011 11:22 PM, James Thompson wrote:
>> http://www.bobvila.com/forums/Tools/posts/42900-craftsman-model-665-256560
>> 
>> >> I have one of these in my hot little hand, but can't identify it. It appea
rs to be a speed increaser/reducer, don't know which. One end has a threaded hol
e which might screw onto a small drill press arbor, and the other end has a 1/4"
 square drive exactly like a ratchet. I am thinking torque increaser, but it is 
more complicated than others I have seen in the past.
>> 
>> Any help out there?
>> 
>> Jim Thompson, the Oldmillrat in Riverside California
> 
> > When I was turning Sputnik - yeah - Sputnik components out of brass to make 
up sprinklers ;^) I had to use a device similar looking, in a drill press to cut
 threads in holes. Pressing down would drive the tap, and raising the device wou
ld reverse the tap's direction.
> 
> Does you unit exhibit this type of action Jim?
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