water level ( was Re: Aligning Rails (or ways) on CNC router

If you want a more accurate water level, get a glass tube from a
hobby store, probably a foot length is common. 3/8 would be about a
good size. don't go smaller than 1/4, and 1/2 is not adding anything.

1) then print a sheet with lines on it, 1/8 inch apart, every other
line bold or dotted or something.
2) secure your glass to a piece of wood,
3) paper behind it on a 45 degree. for set-up, 15 degree for better
accuracy.
4) connect your tubing,
5) rotate until your lines are horizontal.

You are making what looks like liquid filled manometer, you can find
data on manometers on DWYER. this is cross pollination of
ideas/technology.

Since water will find it's own level, it will move thousands of an
inch. it's just hard to see with your eye.
http://www.meriam.com/micromanometer.htm

You could use a conducting liquid and put an electrode on your
micrometer. (Dwyer again, Microtector (trademark name))
http://www.dwyer-inst.com/htdocs/pressure/1430.html

This method allows the slope of the glass to amplify what your eye
sees.
http://www.dwyer-inst.com/htdocs/pressure/424.html

the shallower the angle, the greater the movement of water. If you
go too shallow, then you probably would be well served by adding
tubing to the top of the glass and letting that go to a catch pot of
some sort. The proverbial mayonnaise jar ?

and food coloring is helpful.

Read the level, not the meniscus. The meniscus is the curved part of
the water in the tube, the water will lay flat, and then rapidly
curve upwards as the surface tension pulls it towards the glass.

I have heard of hook gages, but not used them. Seems these also
might offer accurate readings. Just not sure how you would calibrate
these. But they look like they could be adapted to some sort of
electronics with neat blinking lights.
http://www.dwyer-inst.com/htdocs/pressure/1420-1425.html


I'm learning (again) to read all the instructions first.
how does that go again ???

#1) place gun to head
#2) pull trigger
#3) after removing bullets

I'll let you figure out how calibrate the paper lines to the top of
your rails.

Dave