12" machinist level

OK - I get it. The level was so far out - an amount that exceeded the bench or surface under the level, so that there was never going to be a position to start from. You needed first to get it to the point the bubble would cross in any fashion. Consider yourself no longer new at dealing with them, and keep an eye out for the next HM member who took took a level apart - he may need you!
 
I have a 12 inch precision level that is marked .0002 over 10 inches. It so sensitive that if I hold it in my hand the bubble will move from my body heat. The level was close from the factory but was not calibrated perfectly. Do I care? No. I have a scribe mark on the body of the level which allows me to use it the same way every time. I set it on top of 123 blocks sitting on the flat ways so that the level clears the V-ways. It doesn't matter if the lathe achieves absolute level. All that matters is the relative level of all the parts in relation to the rest of the lathe. Because I bought my lathe new I was able to get the taper out of it with just the level but as beds wear the level will only get you close and you'll need to turn some collars and measure them for the final test. Max wear usually happens about a foot out from the headstock.
 
When I opened one of a precision levels I bought, it has a differential screw to adjust for balance. I put 3 wood screws at around a flat board and used that as a way to calibrate. At each end of the level, I put a piece of parallel at the bottom.

As some said, it can be chasing a devil. It's fun and good to get close to precision god.
 
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nnam said:
When I opened one of a precision levels I bought, it has a differential screw to adjust for balance. I put 3 wood screws at around a flat board and used that as a way to calibrate. At each end of the level, I put a piece of parallel at the bottom.

As some said, it can be chasing a devil. It's fun and good to get close to precision god.
Click to expand...
Here we have have again the 3-point adjust to the surface under the level. @GunsOfNavarone had a legitimate case for needing that, because his level was so very far off, there was no point it found level, regardless the rotation.

I only needed a flat MDF board, put down on the bench, fixed so it would not rock, and it was not quite level.
The rotation with a known level found the horizontal line. Then I just used that line to place the level being tested.

If without a known good level, it is still no problem. You end up with two lines from when you reverse the level.
The good line is the one that bisects.

Adjusting the platform as well then has 5 variables affecting each other in classic chase-your-tail mode with the possibility of non-convergence, instead of only two. I admit to the fun part. I do it too!
 
epanzella said:
I have a 12 inch precision level that is marked .0002 over 10 inches. It so sensitive that if I hold it in my hand the bubble will move from my body heat. The level was close from the factory but was not calibrated perfectly. Do I care? No. I have a scribe mark on the body of the level which allows me to use it the same way every time. I set it on top of 123 blocks sitting on the flat ways so that the level clears the V-ways. It doesn't matter if the lathe achieves absolute level. All that matters is the relative level of all the parts in relation to the rest of the lathe. Because I bought my lathe new I was able to get the taper out of it with just the level but as beds wear the level will only get you close and you'll need to turn some collars and measure them for the final test. Max wear usually happens about a foot out from the headstock.
Click to expand...
Well you're smarter than myself. Had no idea the pandora's box I was opening. Live and learn...
 
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