need help with math problem

[ozzie46]

I am building a boring head and need some help with the feed screw graduation markings.

I am using a 1/4- 20 feed screw and as I am no math whiz I need to know how far the slide will move with one revolution of the feed screw so I can come up with some sort of graduation markings. 1 thru 10, 1 thru 20?

Please don't post formulas as I have never learned how they work. They look like Greek to me. I just barely was able to do addition,subtraction and multiplication. Pre so called "New Math" of the sixties.

Will post pics of boring head soon.

Ron

 

[kcmillin]

The thread being 1/4 20, means there is 20 threads per inch. So one revolution of the dial will move the head 1/20th on an inch.

This would be .050" per revolution. If you make the dial with 50 markings this would equal .001" graduations. This would be the radius and not the diameter. Just like a lathe.

That is a good choice for threads on a boring head.

Kel

 

[ozzie46]

Thanks Kel, Is it possible to put 50 grads on a 1/2 dia dial?

I just guess at the threads. I must have seen it before and it was in my subconcious because I'm not that luck to pick the right one out of thin air. I read everything Ican find on the web about machining so it must have stuck from some where.


Ron

 

[Maryak]

Ron,

If you put 25 grads they will be approx 1/16" apart and equal 0.002" with the thickness of the lines involved interpolating half way or 0.001" should be OK.

Just my thought on it.

Best Regards
Bob

 

[ozzie46]

Thanks Bob, All info is welcome. Probably easier to find a 16 tooth gear in m y scrap err parts box. ;D ;D


Ron

 

[ozzie46]

OOPS I mean 25 tooth gear!

Ron