In a hobby shop like mine I am always looking for a quicker or better way to make my parts.
I have seen the Tapmatic tapping head and others similar in nature for sale on the net.
They are quite expensive for hobby use so in looking around I found this Supreme Reversable Screw Driver and
gear reduction from the way back time. (Some say old timey).
Anyhow I bought one on the bay for $10.00 including shipping! Had to try that! It has a 1/2-20 nose thread
so I put on an old Jacobs chuck. The whole thing seems a bit unwieldy but worth a try.
Disappointed with it when I first checked it out. Sloppy, very sloppy, so sloppy that if spun up in the drill press
it would scribe a circle with the tip of a tap of about 5/8" in diameter.
The gear reduction was nice, smooth and the unit would reverse. After taking it apart I decided to take up some of the slop
by simply adding a small copper washer under all three of the screws holding it together. The washers are #16 solid copper wire
that I hammer formed to be flat. They are still a bit thick but I was able to just keep the fixing screws snug. This allowed the unit
to operate in the proper fashion and get rid of that 5/8" circle. Trick is to not get it too tight, if you do it will not work properly.
The Chuck gripped that 1/4-20 better than it was suppose to. Never slipped once in tapping 72 holes 1/4-20 by 5/8 deep in aluminum.
Requires a bit of effort to run that tap all the way to 5/8 but it works. Reverses and then pull the quill up and on to the next.
One other key to getting this to work is to clamp the work to the drill press with at least two clamps. I do not want that plate
spinning around or that tap to snap. Here is a post for the clamps seen in the picture:
http://www.homemadetools.net/forum/d...9987#post71653
Now, you do need to turn off the DP motor prior to reversing but that is not all that much trouble considering how much labor
I saved by not having to hand tap 72 holes.
Cheers, JR
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