Calibration Cycle for Standard Iron & Steel Plate Gage

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metalfabpm

what length of calibration cycle will an iso auditor accept, or is it less hassle and cost effective to just buy new ones each year
 
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Wes Bucey

Prophet of Profit
what lenght of calibration cycle will an iso auditor except, or is it less hassle and cost effective to just buy new ones each year

Welcome to the Cove. :bigwave:

What is an iron and steel plate gage?
I understand Jim's query to mean WHICH type of thickness gage is used. I'm aware of several types of fixed dimension go/no go gages plus a few spring loaded ones for measuring go/no go attribute plus, of course, instruments ranging from hand held verniers and micrometers up to air and laser gages which measure thickness characteristics at discretion and accuracy of up to 50 millionths of an inch.

Offhand, I'd say that the first task should be regular and frequent "verification" by checking readings against Standard bars to assure an attribute gage still reads in the allowed tolerance range. Actually "calibrating" the gages to the point of adjusting the gage to meet the tolerance range is strictly an economic decision.

An instrument which measures characteristics (i.e. not just go/nogo, but the actual measurement) needs BOTH frequent verification and calibration when required (certified traceable to NIST).

In my own machining company, we verified gages and instruments against Standards every shift they were used. Suspect gages and instruments were sent to independent specialists for confirmation. Decisions whether to replace or calibrate/repair were on a case by case basis.

Believe me, setting arbitrary time spans for verification/calibration/replacement regardless of the frequency in which the gage or instrument is used can be wasteful and costly. A micrometer which sits in a box on a shelf in the tool cage for a year without use probably does not need to be sent out for affirmation of its status, whereas the one in an operator's pocket used on a daily basis may need to be replaced as frequently as monthly or even more often, especially if the spindle and anvil are in continual use with abrasive surfaces (like hot rolled steel sheets or plates.)
 

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silentrunning

In addition to what Wes said, don't think that just buying new micrometers guarantees accurate measurement. There is a lot of junk on the market today. I do a complete Gage R&R when new Mics and Calipers are purchased. Many of them never make it to the work floor.
 

Wes Bucey

Prophet of Profit
In addition to what Wes said, don't think that just buying new micrometers guarantees accurate measurement. There is a lot of junk on the market today. I do a complete Gage R&R when new Mics and Calipers are purchased. Many of them never make it to the work floor.
Wow! What a great addition to the discussion. It is absolutely true that junk is being sold - we go back to the old saw about "penny wise and pound foolish." I've seen R & R on new stuff that didn't measure close to the same on five trials and some micrometers fresh out of the box that were better suited to use as nutcrackers than measuring instruments because their mechanisms were so "clunky."
 

AndyN

Moved On
what length of calibration cycle will an iso auditor accept, or is it less hassle and cost effective to just buy new ones each year

Simple - whatever cycle your calibration data shows is effective! Even if you decide to junk an item of measuring equipment, you still have to show it measured within the expected tolerance during its life! Otherwise, it could have "gone out" just a few hours/days/weeks/months after being out into service!
 
M

metalfabpm

i'm refering to starrett No. 281 & No.283 machine operators carry with them to pull stock &drop off from the steel bay. a final check is done with a mic. or calipers at there machine to verify. to many tools get damaged out there.
 

Jim Wynne

Leader
Admin
i'm refering to starrett No. 281 & No.283 machine operators carry with them to pull stock &drop off from the steel bay. a final check is done with a mic. or calipers at there machine to verify. to many tools get damaged out there.

This is a Starrett 281. You should be able to check them with pin gages or blocks periodically and let it go at that.
 
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iamtroll

I would think that you could identify them as "For Reference Only" since the machine operators use a micrometer or caliper as the final check before processing and these are for stock picking only.
 
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