DIY transit from junk

[Toolmaker51]

Not only correct, Marv, precisely so. Genau.
On lathe beds, the Vee's are not in plane to the flats. Use 1-2-3's or two of any identical materials higher than Vee's interfere. Whatever checks are made longwise, check as many 90° to bed. This labor results in superior, or at least enhanced, machine performance.
Sensitivity is everything speaking of bubble levels. Good as their #98 is, the 199Z is .0005 per foot, Mitutoyo has one higher yet, at .0002 per foot!
A user could determine some degree of sensitivity on any level on a decent clean surface, two 1-2-3 blocks, an accurate scale/ tape, and feeler gauges. By spacing blocks a known distance apart, get an apparent level reading with paper shims at one end, then create an incline via feelers. A half bubble is conveniently interpolated once you know what combined stack of feelers generates it.
When leveling machinery, I start off with two decent construction grade [torpedo] levels and a bullseye. Orientation of torpedoes is parallel to machines X and Y. I add a bullseye when both are not easily seen from one position, a monitor. Then I break out 2 precision levels. You can save a lot of steps and crawling around with feeler gauges. Whatever deflection a bubble shows, lift lower side with a feeler to zero, lets say .007 works for 1 foot. If the leveling screws are 3 feet apart, low side needs roughly .021 for level [remember to remove feeler!]. If screws are not spaced so conveniently, divide the amount needed [in 1 foot] by 12, and multiply that for screw spacing. Example = .007/12 is 0005834 [rounded] x 54" is .031.
There are two well known ways to measure lift or lowering. 1) Bandsaw a shallow taper leaf of steel. Push it under base till interference is felt. Mark that with felt-tip or red pencil. Measure with a caliper. 2) Determine the pitch of elevation screws, calculate what 1/2 and 1/4 turns deliver as movement. Paint a small dot on the head to render control of turns.
I employ both together, some bases have a LOT of screws!

Any transit short of theodolite or collimator seems hard pressed to interpret accuracy over something short as a lathe bed, within confines of your building, and certainly at a height not comfortable for viewing. Even less so across the bed. Probably fine for initial set up, placing a stock feeder, etc.

Surveyors read over distance that will create a significant sine figure, checked to the range rod. Subsequent placements reinforce the calculations.

[Papa Smurf]

Thanks to both Marv and Toolmaker51 for their prompt and full replies. I knew the answer was here!

Hi-jack off

[Toolmaker51]

Realizing you have an instrument already, here are my other go-to devices.
Hand Level [aka Locke Hand Level] been around over a hundred years; newer ones look different but work identically. Great for landscape and rough leveling of forms etc. I posted it and staff, sort of built into a range rod, sometime back...http://www.homemadetools.net/forum/s...ne-sight-43371
Split-Image Transit.


Here's Wikipedia on transits, and various forms they've evolved into.
https://en.wikipedia.org/wiki/Level_(instrument)
Like you Papa Smurf, I've a legitimate surveyor's outfit; analog, old school, whatever someone might call it. It's a pleasure to use, even though I only level and drop points at short distances. Way better than working over obstructions for same information. While not machine leveling, I have set infeed tables and such hardware leading to a machine.

[mklotz]

I have one of those split image transits tucked away somewhere. Yet another thing for my heirs to discover and puzzle over.

I wish I could be around when they clean out Garaj Mahal and my office. Imagine generation X-ers with a dial test indicator in one hand and a home-made waveform generator in the other. I can hear the repeated chimes of "whatever" already.

[marksbug]

Exactly!

My rule for saving offcuts is: it doesn't go in the scrap bin until it weighs less than a nickel (5 grams).

that makes me feel more normal as thats about what I do also. "it aint junk till it's dust or chips" weve always recycled stuff. I cut the tops off of pistons for nice aluminum slugs to make whatever out of(steering wheel addaptor,different size cylinder head and crank case line up tools, head gasket triming tools and much more. old v8 camshaft cut up and make valve seat drivers for each piticular seat size I need to drive into cylinder heads. exersize equipment is fulll of sweet steel and other stuff. old washingmachines are great for making stuff with the parts. the old chromed agitator shafts were so awesome for making many things including a bead roller, axles for dollys, lots of stuff. Ive even made tooling out of old 1953 desoto hemi water pump pully because it was sized just right....it was quick, looks rough but did the job at hand.Ill rework it at some point. even old pressure plates can be repourposed!!!( clutch&pressure plate from car/truck). just be sure to make real well what it is when your done or you may go looking for it and discover it's now something else....dam I was pissed!!!!

[marksbug]

hmm Ive got a tranist , probably over 100 years old9 it was grandpaws, he passed in 77 at a ripe old age of...77 and Im sure it was used long before he bought it and did surveying at some time in his life....I kinda doubt I could figure a way to check squat with it....well possiably a squat. I am however in the prosess of building a barn..shed...I hope I cant find it.

[thirteen]

I formerly calibrated survey instruments. Pre-electronic era some open frame transits had 20 second bubble vials. Electronic era total station models had choices of 5 second and 2 second accuracy and electronic tilt sensors. Construction grade transit levels also needed to be adjusted for plunge which could bow from top to bottom which is less of a problem when you could flop the scope on a transit.