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The 'What is this tool' thread.

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  • The 'What is this tool' thread.

    There seems to be a quite a few 'What tool is this, ID this tool, what is this tool called, etc.' threads. I finally have a tool that I am clueless about and was pondering over how to write up my 'What is this tool' thread. Then I thought about how many of these threads exist and thought it would be nice to have one thread for all of them. I guess I'll see how it goes.

    Anyhow here is my 'What is it' tool that I found today while cleaning of the back ledge of my work bench. I remember this tool being in my grandfathers drill box since I can remember but have never seen it used or asked what it was for.

    I assume the triangle shaft is chucked in the drill, if you spin this shaft the two parts of the body counter rotate with each other. The output shaft can be turned counter clockwise or clockwise from a "neutral" position. Turning the output shaft clockwise moves the shaft in about a 1/2" and locks it with the upper body. If you than turn the input shaft and hold the lower body with your hand the output shaft will turn at a estimated 20:1 reduction in the same direction the input shaft is turned. Turning the output shaft in the counter wise direction it locks with the lower body and the same deal happens, however the input and output shaft turn in opposite directions from each other.

    Supreme Chicago Pat.No.2780944

    On the other side it says: Model number 4100



  • #2
    It's a tapping head. Hold the body to keep it from rotating. Push/pull to engage forward and reverse.


    • #3
      Tapping head is my guess


      • #4
        That is a device you put on your electric drill to either slow it down,or speed it up. I can't recall if it works 2 way. I've had one since the 50's,and never use it.


        • #5
          That is a speed reducer to drive screws with. The triangle end goes in the drill chuck and a screwdriver bit, usually phillips, in the other end. With the drill turning, hold one half stationary and it turns the screwdriver forward. Hold the other half and it reverses.
          Kansas City area


          • #6
            Agree on the speed reducer. If it were a tapping head it would be adjustable for setting the torque. Given it is also necessary to grip the housing to get the speed reduction to work, it is also a crude clutch.


            • #7
              Actually it is a power screwdriver attachment. My dad had one when I was a kid.
              It was one of the first things he bought with the money he had left over when he quit smoking.
              Guaranteed not to rust, bust, collect dust, bend, chip, crack or peel


              • #8
                I have that exact item, that I bought for about a dollar at the local Junque Shoppe. I, too, thought it was a tapping head, but wasn't sure- I figured an early, cheap version at worst, but hey, for a buck, why not?

                When I got it home, it didn't act- moving the parts by hand- like a classic tapping head, so I was stymied a bit. I'd been meaning to post it here for a "what is it?" but looks like I got beaten to it.

                Not surprised it's a speed reducer/clutch, since drills with a variable-speed trigger (or really, even reverse) is a relatively recent innovation. I have more than a few older hand drills where all you get is on and off, righthand twist only.

                I might have to give it a try, just to see how it works.

                Doc's Machine. (Probably not what you expect.)


                • #9
                  Not all tapping heads have adjustable torque. In fact, most don't. That unit appears to be a speed reducer as It doesn't seem to have anyplace to screw in an anti-rotational rod to the body, and the exit end doesn't seem to have a collet chuck meant for taps.


                  • #10
                    Yep, it's definitely an old portable drill speed reducer.
                    I used to see them all the time, but with the advent of variable speed drills I haven't seen one in years.

                    Here's a couple of links you may find interesting:


                    Home, down in the valley behind the Red Angus
                    Bad Decisions Make Good Stories​

                    Location: British Columbia


                    • #11
                      A search in the google patents search (2780944) says is a REVERSIBLE DRIVE FOR POWER TOOLS issued in Feb 1957
                      I think my Dad had one.

                      I would rather have tools that I never use, than not have a tool I need.
                      Oregon Coast


                      • #12
                        It's for offhand tapping. Push to thread. Pull back to back out. Mcmaster Carr used to sell them.
                        Then again, what haven't the sold.


                        • #13
                          Its a planetary gear reducer/screw driver. It may even have "Versamatic" stamped on it somewhere. They were the hot ticket before variable speed drills and power screwdrivers. You put a screwdriver in one end and chucked the other end in your 1/4" power drill. Depending on whether you held the top section or the bottom section stationary, it would drive the screw in, or reverse and drive the screw out. My dad and I used to build wooden rowboats back in the 1950's. and the plywood bottoms got a brass screw every 2" all the way around the perimeter of the boat. At first we did it all with hand screwdrivers ---finally bought one of those units, and thought it was the finest thing since sliced bread!!!----Brian
                          Brian Rupnow


                          • #14
                            Picked up the exact same item at a flea market ($1) a few years ago. It is a speed reducer - 7:1 IIRC. It had worn bushings so I cut it open. It has a very well made planetary gear system which I plan to use on something someday!!!



                            • #15
                              I have the identical speed reducer, Bought it when building a fence and used robertson screws. Have not used it in a coons age since having variable speed drills and screw guns. Peter
                              The difficult done right away. the impossible takes a little time.