Checking caliper measurements
- Thread starter dtucker
- Start date
You will have to contact a metrology company or have someone you know take them to work and have them checked.The fixture they use is so expensive that you cant afford it.The other thing you could do is find somebody with gage blocks that are held to millionths..Or if you have a high grade set of 123 blocks you will get an idea if they are accurate.
NorCalMikie
Gold $$ Contributor
Roger: Well said. KISS!! 
I take it you mean either dial or verneer calipers, right? If that is the case, all you have to do is to:
First, make sure there is no dirt on the measuring faces,
Second, close the faces with the same force you use in your measuring, and
Third, make sure the pointer is setting directly on the zero.
Done!
First, make sure there is no dirt on the measuring faces,
Second, close the faces with the same force you use in your measuring, and
Third, make sure the pointer is setting directly on the zero.
Done!
dcali
Bullet Maker
They do make proper calibration gages: http://www.mcmaster.com/#caliper-accessories/=c8vj4w
But you won't like the price at over $400.
A set of gage blocks would be cheaper: http://www.grizzly.com/outlet/81pc-Precision-Gage-Block-Set-Grade-2/T10062
but will still run $150 or so
Calipers are only good to +/- 0.001" anyhow (and that's just the good ones). So as a last resort, you can use any object of known thickness as a poor man's gage. As was suggested, a bullet diameter makes a good one, at least for smaller measurements. I wouldn't assume that calipers that are good for a .500" measurement are necessarily good for a 5.500" measurement.
But you won't like the price at over $400.
A set of gage blocks would be cheaper: http://www.grizzly.com/outlet/81pc-Precision-Gage-Block-Set-Grade-2/T10062
but will still run $150 or so
Calipers are only good to +/- 0.001" anyhow (and that's just the good ones). So as a last resort, you can use any object of known thickness as a poor man's gage. As was suggested, a bullet diameter makes a good one, at least for smaller measurements. I wouldn't assume that calipers that are good for a .500" measurement are necessarily good for a 5.500" measurement.
damoncali said:
To verify that your calipers or measuring tools are telling you the truth. That your measurements are correct.
If, for instance, your calipers don't read what this gauge says that it should, in this case .050": http://www.amazon.com/Mitutoyo-611105-531-Rectangular-Steel-Block/dp/B001OBSGAA , then you know your tool needs to be reset or calibrated so that it does.
fguffey
Banned
As to pin gages, I use hole gages, when it comes to pin gages I find the taper gage more useful, I have an in-line, butt and angle grinder that gives me endless options, and reamers, nothing like having a reamer to finish a hole, but to make sense of any of this it must be understood the datum is not a line even for the person reading blue prints.
A caliper reads .000 when closed, the rest of my micrometers came with standards as with a set of five from 1.000" to 5.000", each micrometer has a standard starting at 1.000" and going up to 5.000".
And then there is the companion tool to the press, the feeler gage.
F. Guffey
A caliper reads .000 when closed, the rest of my micrometers came with standards as with a set of five from 1.000" to 5.000", each micrometer has a standard starting at 1.000" and going up to 5.000".
And then there is the companion tool to the press, the feeler gage.
F. Guffey
expiper said:
Roger, actually . . . they're not. Their out of house specs are .0005", as in .3080" to .3085" for a nominal .30 caliber bullet; everything has tolerances!
If you have a drill set with numbered drills and drills from 1/16 to half inch check with then, also i wanted a set of micrometers so went to Harbor Fright they had on sale a set of one inch to three inch micrometers also if you can find a 20% discount from one of thair ad's use that also
damoncali said:
I use them to measure;
the neck of chambers
the throat in revolvers
the inside of case necks
as a reference for measuring bullet diameter
as a reference for measuring loaded cartridge neck diameter
I use them to locate holes in the press for fabricating new press parts.
I also put pin gauges in a collet neck die to pre compress powder in a case, if it might squish a bullet.
So I have a set in the shop for gunsmithing, and as set in the reloading room.
Surely for reloading purposes it is mostly the repeatability and consistency of the measurement that counts, rather than the actual number...
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