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Torque wrenches and drivers - How to perform MSA (measurement system analysis)

Miner

Forum Moderator
Staff member
Admin
#6
mnavarro said:
Hi, Miner. It´s a torque wrench
If the torque wrench is used as the process for torquing a fastener, you would not perform an MSA. but a capability study using a torque analyzer as the measurement device. You would perform an MSA on the torque analyzer since it is the gage.

If the torque wrench is used as an inspection device to check breakaway torque, or the torque required to additionally tighten the fastener, you would have to perform a destructive/non-repeatable MSA. You can search the threads in this forum for information in that. There have been several recent threads on destructive MSAs.
 
#7
Thank heavens.........

for that bit of advice.:applause:

How many times do folks 'calibrate' their torque drivers, instead of making them part of a maintenance program, after they've established the capability?:rolleyes:

Nice advice Miner!!:agree1:

Andy
 
#8
This has been by our customer and our TS auditor:

We did attribute MSAs on our click over type torque wrenches. Two people got a torque wrench and a torque spec. I had 10 units (that I was using for multimeter MSAs). I loosened 1 of 2 nuts on randomly selected units. Appraiser 1 checked all the nuts and listed which ones were properly torqued and which ones were not. I loosened the same set and let Appraiser B at them. Same answer. We then repeated with a different set of nuts loose and Appraiser B going first. Two Appraisers, 20 parts, 2 trials, done.

We calibrate (or validate) our torque wrenches annually against known standards. Since they cannot be adjusted, any wrench that begins to trend out of tolerance is removed from service.

We use torque specifications to get fasteners "tight" without breaking them loose from the substrate(which is sometimes steel and sometimes circuit board).

But Miner is right, too. If you have to meet a customer spec for torque, say for a safety item like a seat belt mount, I would follow his advice.
 

mnavarro

Starting to get Involved
#9
:agree1: Hi, Miner. In my case, I use it as a final inspection device and to additional tighten. I´m going look at site for more information. Thanks a lot.
 

Miner

Forum Moderator
Staff member
Admin
#10
mnavarro said:
:agree1: Hi, Miner. In my case, I use it as a final inspection device and to additional tighten. I´m going look at site for more information. Thanks a lot.
Your welcome. If you cannot find the specific information in your search, I will be happy to help further.
 


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