Looking for someone who has very accurate, well calibrated measuring capability

B

Boyd Allen

Active member
I have several micrometers, including one Fowler 1-2 that has a 1" standard.
The problem is that my other micrometers tell me that it is about .0003 long. Now before you explain that I really don't have any way to know what I am dealing with, let me say that I am acutely aware of that, and that that is the reason for my post. I would like to have my "standard" measured, and I would also like to hear about how accurate these things generally are. I know the rudiments of adjusting a micrometer, and if I had something that was close to an inch, that I could use as a standard, I think that I would be more likely to stay on top of my calibration issues. I already am aware that temperature plays an important role in accurate measurement, and I have a stand that I can use to minimize body heat transfer.
 
Since you've invested in several micrometers, perhaps investing in a couple deltronic pins would be cheap insurance.
 
Boyd Allen said:
I have several micrometers, including one Fowler 1-2 that has a 1" standard.
The problem is that my other micrometers tell me that it is about .0003 long. Now before you explain that I really don't have any way to know what I am dealing with, let me say that I am acutely aware of that, and that that is the reason for my post. I would like to have my "standard" measured, and I would also like to hear about how accurate these things generally are. I know the rudiments of adjusting a micrometer, and if I had something that was close to an inch, that I could use as a standard, I think that I would be more likely to stay on top of my calibration issues. I already am aware that temperature plays an important role in accurate measurement, and I have a stand that I can use to minimize body heat transfer.
Click to expand...

Boyd, there are measurement standards available for purchase that are certified by the National Institute of Standards (NIST). The NIST also offers a service to check your standards, 'taint cheap, but then again who is to say they are correct??

http://www.nist.gov/calibrations/index.cfm
 
Boyd,

I'm not sure how common they are but I lucked into a used 9-pc set of Starrett Webber measurement standards----ranging from .0625 to 2".

I don't remember exactly what I paid for this set but it was not terribly expensive.

I was told by a Starrett guy that the tolerances on these blocks are within a "few" millionths.

As you can imagine, I'm now fairly confident in the calibration of my micrometers.

You might look around for a deal on something similar.

A. Weldy
 
I agree with buying a gauge pin. I have a couple to check neck diameters. You can also get one the is .2620" for checking loaded round clearance. The class X pins are good to .00002" I think. That is pretty small. I will try and post a link.http://www.gageshop.com/shop/index.php/cPath/31?osCsid=nvt8irq10pv3oueaes6uhicj26

You can order these from almost all of the industrial supply placee, MSC, McMaster Carr and such.
The class ZZ pins are cheaper but the tolerances are about double of the X ones. It is still a constant that you can use every time you use your mic. If you check out the site, Long Island Indicator, they say you should get a standard about the same size you are trying to measure, to help eliminate errors in the movement of the mic. So if you are measuring a bullet that is .2425", get a pin that size, not one that is 1".

Hope this helps.

Joe Hynes
 
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