We have some old steel/iron 90degree angle blocks that are being calibrated. The company says that they should be square within .0002, but that many companies go to .0025. We measure to .003 inches. The face that we measure and butt against is 10 x 8 inches. Sometimes we use the entire surface to measure and butt against. Any info on the proper calibration is appreciated. Thanks in advance
Steel 90 Degree Angle Block Calibration
- Thread starter gpainter
- Start date
I don't have the specs for your angle blocks handy, nor do I specialize in mechanical calibrations. But I do have a couple of thoughts in general metrological principles.
1. Unless there is a compelling reason, I recommend always certifying your standards to manufacturer's specs. Sounds like you know what they are anyway.
2. Sounds like your standard has "apparently" appropriate specs for what you want to calibrate with it (with the qualifier that this is not my expert area).
3. Something sounds questionable when an outside lab is trying to "sell" you on certifying your standard at less than it's designed specs.
If I were speculating, I would guess it possible a vendor may not have adequate uncertainty to correctly calibrate to its full specs. So in the interest of still keeping the business, suggests calibrating to lower specs.
If the unit cal'd by the standard is +/-0.003, it is not desirable to have the standard certified only to +/-0.0025. You are barely better than 1:1 uncertainty ratio.
My vote is to find and use an adequate vendor that has correct capability to certify your standard to it's full specs (especially since it appears you need full specs to adequately calibrate your units).
Do what's needed to assure risk to products at your company is minimized.
That's my two cents. Hope that is of some help.
1. Unless there is a compelling reason, I recommend always certifying your standards to manufacturer's specs. Sounds like you know what they are anyway.
2. Sounds like your standard has "apparently" appropriate specs for what you want to calibrate with it (with the qualifier that this is not my expert area).
3. Something sounds questionable when an outside lab is trying to "sell" you on certifying your standard at less than it's designed specs.
If I were speculating, I would guess it possible a vendor may not have adequate uncertainty to correctly calibrate to its full specs. So in the interest of still keeping the business, suggests calibrating to lower specs.
If the unit cal'd by the standard is +/-0.003, it is not desirable to have the standard certified only to +/-0.0025. You are barely better than 1:1 uncertainty ratio.
My vote is to find and use an adequate vendor that has correct capability to certify your standard to it's full specs (especially since it appears you need full specs to adequately calibrate your units).
Do what's needed to assure risk to products at your company is minimized.
That's my two cents. Hope that is of some help.
E
energy
This is a good one!
A long time ago, my QA Manager answered this exact question for me. We had two of these blocks and they were on the Calibration list. He said, "Take one of our calibrated squares and place them both on our tool grade surface plate. Butt the square up against the block and with our calibrated flashlight, shine a beam where they meet. If you see no light, or just a little, you're good to go. You'll know what +/-.005" looks like". I swear.
gpainter said:
A long time ago, my QA Manager answered this exact question for me. We had two of these blocks and they were on the Calibration list. He said, "Take one of our calibrated squares and place them both on our tool grade surface plate. Butt the square up against the block and with our calibrated flashlight, shine a beam where they meet. If you see no light, or just a little, you're good to go. You'll know what +/-.005" looks like". I swear.
Charles Wathen
Involved - Posts
We use a Squaremaster column to calibrate these. It looks like a Height Gage, but inside is a granite column that moves up and down. This Squaremaster column is calibrated against a standard granite angle.
Your accuracy sounds about right at .0002 total indicated reading. If you were to calculate measurement uncertainy, you probably would have .00005" of error in the measurement.
Your accuracy sounds about right at .0002 total indicated reading. If you were to calculate measurement uncertainy, you probably would have .00005" of error in the measurement.
M
merrick65
Re: Steel Angle Block Calibration
I see where Mitutoyo uses the following tolerances (ref CLTM-1 Mitutoyo Calibration Procedure of Angle Blocks): For blocks with angles <= 30º ± 20 seconds and for blocks with angles between 30º - 90º ± 40 seconds. I know my post is kind of late but I just started looking here.
I see where Mitutoyo uses the following tolerances (ref CLTM-1 Mitutoyo Calibration Procedure of Angle Blocks): For blocks with angles <= 30º ± 20 seconds and for blocks with angles between 30º - 90º ± 40 seconds. I know my post is kind of late but I just started looking here.
M
MysterHK
Just a clarification--MU ≠ Error. He would probably have .00005" of uncertainty in the measurement.
Similar threads
