2018 POTD Thread Archive

Thanks. I cheated and finished my tool on the surface grinder this time. It made a difference in the performance. Usually I just hit it with the pedestal grinder and call it good.
 
I saw an article about differential threads that I thought was very interesting.
I did some research and found some useful applications for the design but mine is just for demonstration.
I used 5/8" X 11 and 3/8" X 16 threads which gives about 0.029 movement for one turn of the crank.
As the handle is turned it threads into the stationary and also threads into the movable block which results in one thread subtracting the distance from the other. Both are right hand threads.

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Some of the uses I found
Very old hand operated printing press
Screw jack
Telescope mirror adjustment
Laser alignment
I am sure there are many other uses also.
Very high degree of accuracy can be attained using different thread sizes.

Enjoy
Ray
 
After some recent welding I decided I really need a cheap, compact dedicated tungsten grinder.

Horrible freight sells this saw blade sharpener with a diamond blade and a motor for $69.

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Removing all the junk leaves this:

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Just need a guard and rest for the tungsten:

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At about a 20 deg angle I get a very nice taper.
Works like a charm.
Robert
 
Finally! After years of using a screwdriver to change the blade on my box cutter, I finally got fed up and made a thumb screw for it. Tool-less blade changes!

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Helps with gripping too.

Robert
 
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