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Author Topic: Caliper calibration vendor  (Read 4329 times)

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Offline kgarrison

  • Posts: 4
  • Gender: Male
Caliper calibration vendor
« on: January 09, 2020, 07:26:02 PM »
My lab is starting to determine uncertainty for our various measurement equipment.


Does anyone have good recommendations for vendors to use (or stay away from) in the southwest part of the U.S.?


I have specifically been tasked with finding a vendor who calibrates calipers, but I know these vendors usually are certified to perform calibrations on several different pieces of equipment.


They would need to be up to ISO accreditation standards and be able to provide documentation of traceability to SI units.


Feel free to reply here or email me at kgarrison@sbcsd.org


Thanks in advance!
Kirk Garrison
Firearms and Toolmarks
San Bernardino County Sheriff's Dept.
Scientific Investigations Division
kgarrison@sbcsd.org

Offline Julie Knapp

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Re: Caliper calibration vendor
« Reply #1 on: January 10, 2020, 10:21:51 AM »
Are you going to use a measurement standard like a gauge block?

Offline Julie Knapp

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Re: Caliper calibration vendor
« Reply #2 on: January 10, 2020, 10:28:39 AM »
We just got our gage blocks recertified for Colorado Bureau of Investigation and used Applied Technical Services out of GA.  No issues and they had them back to us very quickly.
If you have not purchased gage blocks yet and want to,  you can purchase them already certified.  Then, depending on your specified recert. schedule, you would just need to send those out.  You can then use your gage blocks to do your calipers and micrometers; although I prefer a glass slide micrometer to test my digital micrometer...here is a website you can check out:
https://www.pcsllctn.com/services/dimensional-calibration/gage-block-calibration-service/

there are other sites, this is just one. 

:)

Offline Alan Zheng

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Re: Caliper calibration vendor
« Reply #3 on: January 13, 2020, 10:12:19 AM »

You can use this to search for certified calibration of just about anything.

https://cabportal.touchstone.a2la.org/index.cfm?event=directory.index

Offline kgarrison

  • Posts: 4
  • Gender: Male
Re: Caliper calibration vendor
« Reply #4 on: January 14, 2020, 01:59:42 PM »
Are you going to use a measurement standard like a gauge block?


We have our certified gauge blocks we use on a quarterly schedule to do checks on the calipers.


The problem we discovered was that the calipers themselves need to be sent out to be calibrated and certified as well.
Kirk Garrison
Firearms and Toolmarks
San Bernardino County Sheriff's Dept.
Scientific Investigations Division
kgarrison@sbcsd.org

Offline Nat Pearlson

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Re: Caliper calibration vendor
« Reply #5 on: January 16, 2020, 09:22:17 AM »
If your lab requires you to have the caliper as well as the gauge blocks certified, then you have to do it.  I don't think accreditation requirements mandate that.  If you are checking your calipers against a traceable reference standard (appropriately certified gauge blocks), I believe you are meeting accreditation requirements, at least for ANAB.

Nat

Offline Jennifer Floyd

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Re: Caliper calibration vendor
« Reply #6 on: January 17, 2020, 01:32:46 PM »
Nat - it would be because they are calculating uncertainty.  The device you use to make the measurement has to be calibrated prior to service and you include the measurement uncertainty found by the calibrating service when you calculate the uncertainty for a certain measurement type.
Jennifer Floyd
Arkansas State Crime Laboratory

Offline Nat Pearlson

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Re: Caliper calibration vendor
« Reply #7 on: January 17, 2020, 03:19:22 PM »
Good point Jennifer.  I was thinking of the calipers we use for measuring bullets, tools, etc. for which we don't calculate an uncertainty for (yet!).  For our large calipers that we are implementing for firearm length measurement, as Jennifer says, we included the uncertainty on the calibration certificate of for the calipers in the budget for the uncertainty of the measuring process.

Nat

 

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