Adjusting a machinists level?

[arvidj]

For leveling a lathe the calibration does not matter a bit...follow me here.

Only thing relevant is the ways are straight and not twisted. Period.

Agreed. I didn't say what I used it for once it was calibrated. Just responding to the title about how I calibrated mine.

The method you suggest is similar to the one Mikey and I suggested. I just happen to have the surface plate and machinist jacks handy.

 

[woodchucker]

Unfortunately I don't have anything that I can trust to be level. Soooo,
I"m forced to use my unlevel lathe. First I leveled the lathe without tampering with the level adjustment.
Then, adjust and go back and work on the lathe again, then back to the level...(repeat)
Kinda sneaking up on it. I think I have it pretty close now.
One bad thing, If I move the level to different places on the ways the readings change. A LOT.
I haven't stoned the ways but there are no visible burrs. I only wiped them off with a clean rag. Before I pass too much judgment I'll try stoning them but right now it seems like the ways are not ground straight enough to make the level happy. (China...)

it doesn't have to be level, you just have to read the same when you flip it 180.
So if it's just on the first tick, then when you flip it 180 it needs to be on that tick...

 

[100LL]

What would a metrology shop charge to calibrate a 199 Starrett master level? Ballpark. Just curious

 

[Bob Korves]

Calibrating a bubble level is a not very difficult shop job, not a metrology shop job. About the only thing you can do to a bubble level that is not physically damaged is adjust the vial, and the vial is self proving.

 

[ddickey]

Slowly rotate your level on a surface plate. At some point in the rotation your level will find level.

 

[100LL]

SO what’s the point in buying a high quality machinist level? Is there any point?

 

[JimDawson]

SO what’s the point in buying a high quality machinist level? Is there any point?

It allows you to get two ends of a surface in the same plane, like a lathe bed. Most machine tools don't need to be level, but they can't have any twist in them. Level or ''square to the earth'' is a good point of reference. The more accurately you can read that point of reference the more square you are going to be.

 

[woodchucker]

SO what’s the point in buying a high quality machinist level? Is there any point?

it's very easy to calibrate. Don't overthink this. A machinists level is very sensitive. But also very calibrateable. you want it to read the same in either flip of 180. Then it is calibrated.

 

[Bob Korves]

The 199 is quite sensitive, so be ready to take your time calibrating it. It takes some time for the bubble to center, and the level should be tested in exactly the same position with 180 degree end for end turns to achieve the same reading with the level facing both ways. The surface should be level enough that the bubble lines up somewhere near center, with the end of the bubble within the calibrated lines, and spotlessly clean, no debris at all that can cause erratic readings, also a rigid enough setup to not move around. Some kind of fences, like steel bars, can be laid out for returning the level to the same location for each test. Give yourself lots of time to be able to get it right. Sometimes it goes quite quickly, other times it takes longer. The first time can possibly be quite slow, until you get the hang of it. The bubble needs to give the exact same reading with the level in both positions. It never needs to be in the center for doing the calibration.

 

[woodchucker]

. It never needs to be in the center for doing the calibration.

slight correction: It DOESN'T needs to be in the center for doing the calibration.
Both statements are correct. if it winds up being in the center, well, hey you are lucky. But it doesn't need to be. It just needs to read the same.
Bob's idea of a fence is a good way of ensuring the same position. BUT always wipe with your fingers both the surface plate and the level b4 setting down to remove any dust. A machinists level is so sensitive a spec of dirt or dust can affect the reading.