Ron M. answers:

You are right. Mechanical advantage alone does not always measure benefit. A machine either increases force output, or changes the force’s distance or direction of operation. A leadscrew with a high mechanical advantage, one that produces equal or greater output than input, would be useless. A screw is useful because it changes direction rather than force.

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Ron M. answers:

The leadscrew is geared to the chuck with gears that can be changed to suit within reason any ratio you require to produce screwthreads in sequenced cuts that can be repeated time after time

Ron M. answers:

Input …
Think about what you do to a screw to “operate” it. Easy enough, right?

Output …
Think about what happens to the screw when you “operate” it!

No! Both would not be rotary.

Even though the screw is rotating … It is still the “input” motion.

The output motion is the effect of rotations, which will be ……. Linear! (Because the screw moves inward or outward depending on direction of rotation.)

Look at the picture of the bench vise below and think what would happen to the moveable part when you rotate the handle. And that motion is your answer.

Ron M. answers:

I’m not really qualified to answer this question, but would some kind of clock where the kid has to turn the hands be of any use?

Ron M. answers:

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