Precision Level??

Kroll, go buy one of those $90.00 machinist levels on ebay or Amazon. They are typically in the range of 0.0005"/ft or something like that. Good enough for getting you pretty close to level since you will final tune your level with a 2-collar test anyway.

Lathes move over time and you need to check the level periodically. Just bite the bullet and buy one.
 
You can test the level to see if it is out more than they say. just get a reading flip it 180 and see if the reading is the same as the first. I cheat and use masking tape to mark the edge of the bubble. (I have a strong suspicion that everyone knows this trick so accept my apologies )
The best solution I have is to find someone to borrow one from.
 
Watch "Starrett 98 Series level calibration procedure" on YouTube
A good video on adjusting a precision level.
 
Asbestos said:
You can test the level to see if it is out more than they say. just get a reading flip it 180 and see if the reading is the same as the first. I cheat and use masking tape to mark the edge of the bubble. (I have a strong suspicion that everyone knows this trick so accept my apologies )
The best solution I have is to find someone to borrow one from.
Click to expand...

It's one of them things that is obvious once you have been told :) all them small tips can help out people.

Stu
 
richl said:
Watch "Starrett 98 Series level calibration procedure" on YouTube
A good video on adjusting a precision level.
Click to expand...

This video is okay but it is misleading in that the surface you are leveling on must also be level or you will end up chasing your tail trying to get it right. The proper way to calibrate a precision level is to use an adjustable surface. It doesn't have to be a surface plate but it should be flat and have three adjustable feet. You should also have a mechanical means of returning the level to exact same spot when you flip it 180 degrees.

A piece of plywood (3/4" thick Melamine ply works well) with three screws on the border 120 degrees apart is good. You can use threaded inserts of some kind and use screws for adjustment. A small framing square or even three nails is fine to assure the level is referenced to the exact same spot. Then follow the procedure in the attached document.

My personal level is sensitive to 0.02mm/M, or just under 0.0003"/foot. This is sensitive enough to require 20-30 seconds for the bubble to settle. Without the adjustable table it can take hours to calibrate this thing properly. Using the table, it takes minutes.
 

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mikey said:
This video is okay but it is misleading in that the surface you are leveling on must also be level or you will end up chasing your tail trying to get it right. The proper way to calibrate a precision level is to use an adjustable surface. It doesn't have to be a surface plate but it should be flat and have three adjustable feet. You should also have a mechanical means of returning the level to exact same spot when you flip it 180 degrees.

A piece of plywood (3/4" thick Melamine ply works well) with three screws on the border 120 degrees apart is good. You can use threaded inserts of some kind and use screws for adjustment. A small framing square or even three nails is fine to assure the level is referenced to the exact same spot. Then follow the procedure in the attached document.

My personal level is sensitive to 0.02mm/M, or just under 0.0003"/foot. This is sensitive enough to require 20-30 seconds for the bubble to settle. Without the adjustable table it can take hours to calibrate this thing properly. Using the table, it takes minutes.
Click to expand...


He doesn't explain the fact that in one direction on an uneven surface their will be a totaly level surface (I don't think I did either ;) )

Thats why I like the liptons video on it. at 6 mins in he explains the flat plane thingy.


Stu
 
Yeah, I know that there is a line that is level somewhere on a plane but when you try to calibrate a precision level that is extremely sensitive it can take a very long time to find it and then adjust the level. I don't know this for a fact but I would guess that calibration services that certify precision levels use a leveling table for the speed and accuracy it confers. Having used a leveling table for about 10 years now, I would not want to do without it.
 
mikey said:
Yeah, I know that there is a line that is level somewhere on a plane but when you try to calibrate a precision level that is extremely sensitive it can take a very long time to find it and then adjust the level. I don't know this for a fact but I would guess that calibration services that certify precision levels use a leveling table for the speed and accuracy it confers. Having used a leveling table for about 10 years now, I would not want to do without it.
Click to expand...


I think your totally correct that a calibration lab would use some sort of calibrated flat surface or other equipment. Just thought tom explained the method for calibration without any specialised equipment better.

Stu
 
You're right, Stu, Tom did a great job. I am just pointing out that there is a simple way to make the job faster and easier for those of us who use very sensitive levels. I did it Tom's way for years. I just choose not to do that any more.
 
I ended up taking a slightly different approach compared to others here. About a year or so ago I was not ready to level my lathe, but I was browsing ebay or something and found what was advertised as a precision spirit level vial (only the vial) for like 7$ and figured it was worth a try. I believe it was supposed to be 2 or 4 arcseconds per division.
I had removed the headstock for cleaning which in hindsight was not very necessary, but I figured I wanted to learn how to align it anyways. Now that I've got the lathe on a sturdy base and reassembled I used the vial to take out bed twist as best I could . I have absolutely no way of verifying it's accuracy but I'd say It's pretty darn sensitive. The lathe stand is bolted to a concrete floor and the difference in reading when I stood next to the lathe as opposed to a metre away was about one division.
The original plan was to make some sort of quick holder for the vial but I ended up setting it on a vise on top of the crossslide. I then used feeler-gages under one end of the vise to zero the vial and the weight kept the setup sturdy. I proceeded to move the carriage back and forth to read the two ends of the bed, making sure to let the bubble settle, always stand in the same spot, and take multiple readings to make sure the values repeat properly.
With the bed level I then used rollie's dad's method to align the headstock.
This setup is obviously not as convenient and probably not as accurate as a real level, but for 7$ I think it worked very well. The actual accuracy of the vial doesn't really matter since I only cared about the readings being the same from end to end.

Sent from my LYA-L29 using Tapatalk
 
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