# Digital Protractor / Level



## Highpower (Aug 26, 2011)

I added a new tool to my collection a couple of days ago that really surprised me regarding it's usefulness.
I picked up a little 6 inch "Pro 360" digital protractor similar to this one, that has suddenly made my life _a whole lot easier_ for setting up my machines and/or parts to be machined.

I have been fighting with using a pair of Starrett #98 machinist levels, and an import "precision" level for a number of years now - never really fully trusting them because I could never get them to agree with one another. (More on that later...)

This little tool has been *SO* much easier and faster to use than the levels, I really wish I would have gotten one long ago.
Just a recommendation that if you get the chance to try one, I think you'll be hooked too. Setting up angles in the mill vice (to within .1°) is a *breeze* now!


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## Highpower (Aug 26, 2011)

Getting back to my "bubble" levels....

One of our esteemed moderators (Tony Wells) suggested in another thread that using a previously leveled surface plate was a good way to calibrate adjustable levels. I could not verify that my surface place sitting on my homemade stand (3 support points) was indeed level, and Tony also suggested using a marble! _Brilliant!_

So what I did was to first level the plate by shimming the legs of the stand, using my new digital protractor and getting it to read 00.0° in the X and Y planes. I didn't have any marbles (I lost those years ago...) but I did have a few different sizes of hardened steel ball bearings. After using the protractor I found that I could place several of the balls on the surface plate, and *none* of them rolled away! 
	

		
			
		

		
	




Once that was established, adjusting the bubble levels was much easier and consistent. I got them reading equally in 180° planes and the bubble levels showed the surface plate to be off by 2 lines on the vial. I believe that equates to 0.010"/foot on a Starrett 98-6? Not quite enough to trip a .01° reading on the digital protractor. Not sure of my math here, but I put the level on top of the protractor and then shimmed under the protractor until the bubble was centered. The digital reading still showed 00.0°

After fighting for _hours_ trying to level my mill table previously with the bubble levels, the digital unit showed it to be out by .1° in both the X and Y planes.  
But within _minutes_ I had it reading 0.00 all around with the protractor. I *LIKE* this tool!


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## Tony Wells (Aug 26, 2011)

Well, 0.1 deg is almost 0.002/inch, so don't get too carried away.
If you want to get a serious "electronic level" you have to step up to something like a Wyler Clinotronic. 
Mine is good to 3 minutes of arc, although when it was last calibrated, it came out better.....&lt;1 arc second. I need to have it calibrated, but it's pretty sensitive. There are better though. Quite expensive, however.

I have a similar level made by/for Smarttool by M-D building Products. I believe it is rated as accurate as the Mitytoyo. It's very handy.


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## Highpower (Aug 27, 2011)

> author=Tony Wells link=topic=3252.msg23414#msg23414 date=1314399981
> Well, 0.1 deg is almost 0.002/inch, *so don't get too carried away.*



About what exactly?

&amp;^%$


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## Tony Wells (Aug 27, 2011)

I guess I meant in terms of precision. 0.002/in still has to be reckoned with if you are setting up angle cuts on a mill, or checking calibration of other tools or instruments. Or some other work that has to be really close. It's pretty close, no doubt, and most certainly easier to determine when you are within such tolerance than a bubble level.

0.1 deg is 6 minutes of angle. I've been required to work closer than that many times. For my own projects, I try to design around "easy", so you won't see too much on anything of mine that requires that sort of precision.

I most assuredly didn't mean any offense, or imply that you _were_ getting carried away.


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## Highpower (Aug 27, 2011)

Ok, copy that. We are talking about the same thing then in different ways. I didn't mean to suggest that my new little protractor was the end all - be all, in the way of measuring angles. That is why I mentioned when putting my Starrett level on top of it and shimming underneath the protractor until the Starret showed "level". The protractor was not sensitive enough to show the .004" difference (shim). It displayed 0.00 with or without the shim under one end. But the protractor is only 6 inches long - so I guess that pretty much blows their .1° accuracy out the window anyway.   

Oh well. Back to the drawing board.


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## Tony Wells (Aug 27, 2011)

Just curious, did you flip the Starrett 180 and see if it still showed level?


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## Highpower (Aug 27, 2011)

Actually I did not. I had adjusted the Starretts _before_ I tried my "shim" experiment. The bubbles on both of them were 2 lines off to the right when sitting directly on my surface plate (no shim). I flipped both of them 180° and they both still showed 2 lines off to the right. Therefore I *assumed* that if the bubbles were centered, they would still be centered when flipped around again.  :-[ 

I'll have to try to get the plate adjusted a little more to get the bubbles centered and check them again. I *should* have put leveling feet on the stand when I built it, but I failed to do so. Hindsight.....  :


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## Tony Wells (Aug 27, 2011)

That's probably a safe assumption. I was just curious, anyway.

Yep, leveling feet on all stands is a good idea.


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