How to calibrate your own torque wrenches at home

[Kevin Criswell]

Hey guys/gals, in this video I show you how to calibrate your own torque wrenches at home. The adapter I am using can be bought at Harbor Freight Tools for $30.00
http://www.harborfreight.com/digital-torue-adapter-68283.html
(In the video I say $70, but looks like the price has gone down a lot since I bought mine).

Hope you enjoy.

Topic

[college man]

Nice video. 🙂

[Kevin Criswell]

Thanks Paul.

I hope it might help DIYers and techs that don’t have access to a calibration facility and can’t afford a self calibrating digital wrench.

[Andrew M.]

Very nice video. How often should you calibrate a torque wrench? I have a few year old snap on 1/2″ click style that I’ve never calibrated that’s most likely due…

[Kevin Criswell]

[quote=”B16a2″ post=83142]Very nice video. How often should you calibrate a torque wrench? I have a few year old snap on 1/2″ click style that I’ve never calibrated that’s most likely due…[/quote]

I do mine about once every 3 months, but I use them on a daily basis also. I also do a calibration mine right before head gasket jobs or other major work.

[vgs8606]

Any particular reason that you put your complete trust in that cube? To ask it another way, how do you really know that it is actually accurate?

[Willo]

[quote=”vgs8606″ post=83395]Any particular reason that you put your complete trust in that cube? To ask it another way, how do you really know that it is actually accurate?[/quote]

If you watch the vid again, I think Kev answered the question in the first minute of the vid.
40 to 45 seconds
[quote=”Video”]”I’ve had this tested and it showed an accuracy within a tenth of a foot pound of torque”[/quote]

Thanks Kev,
I’ve got a small 1/4 in. and now I know I have to recalibrate it.

[spelunkerd]

That’s a very interesting video. I see your calibrator will check itself internally. Does that mean that your device will not drift out of calibration with changes in time or room temperature? If it does, then I guess you would have to recheck it using an outside reference at regular intervals. But if you do, doesn’t that erode the usefulness, since it is introducing another source of error?

[Kevin Criswell]

To be honest I figure any drift should be small enough not to be a major issue.

Yeah I had the calibration place on the military base check it for me.

[Cory]

I hate to sound like a prick, but the military monkey that ran the calibration may have not done things correctly. On top of that, the machine they use to calibrate with was also calibrated from another monkey… err, who knows what’s going on in the loop. :side:

I was a PME Calibration Technician in the Marine Corps, and personally had to pull someone aside because he was adjusting things way out of standard readings; I wasn’t even the TI Inspector (who so happened to stamp approve his work). At the end of the day, I helped changed procedures in hopes of keeping this from happening again; we also sent a report to Marine Headquarters but unfortunately never heard back from theme.

Maybe I’m over-analyzing, considering cars pull over when they break down and military aircraft… fall out of the sky when they break down. In most cases, most of the Marine techs I worked with worked with full integrity and with correct knowledge.

[Bill]

C’ummon Guys. Nothing in this world is fool proof. Kevin took the time to show this to us to save us money in the long run. If you think it’s B.S. then use your wrench uncalibrated or pay the BIG BUCKS to someone who don’t give a shit to calibrate it for you. Who the hell even knows if their equipment is accurate.

[Cory]

I didn’t mean to sound like a punk; I simply wanted to mention the faults with a calibration facility. In our modern high tech society, we haven’t perfected ‘verification’.

http://www.hyundai-forums.com/233-rb-2012-accent/138090-dealer-over-filling-oil.html

[Rob]

[quote=”Raistian77″ post=83188]
I do mine about once every 3 months, but I use them on a daily basis also. I also do a calibration mine right before head gasket jobs or other major work.[/quote]

Calibrating never hurts, and if you can do it cost free you might as well, but as a guideline for others it seems a bit excessive. Two companies i worked for had them calibrated and certified once a year, along with the meassuring equipment. One does turbine overhauls, the other was a machine shop.. they did use top quality (analogue) torque wrenches, but i’m still tempted to say once a year, or after an incident that might have damaged it, should be enough for most applications.

What sort of deviations do you find after 3 months? Not saying you are wrong for doing this, if i could do it myself i would probably do it just as often 😉

[Kevin Criswell]

[quote=”Rob36″ post=84701][quote=”Raistian77″ post=83188]
I do mine about once every 3 months, but I use them on a daily basis also. I also do a calibration mine right before head gasket jobs or other major work.[/quote]

Calibrating never hurts, and if you can do it cost free you might as well, but as a guideline for others it seems a bit excessive. Two companies i worked for had them calibrated and certified once a year, along with the meassuring equipment. One does turbine overhauls, the other was a machine shop.. they did use top quality (analogue) torque wrenches, but i’m still tempted to say once a year, or after an incident that might have damaged it, should be enough for most applications.

What sort of deviations do you find after 3 months? Not saying you are wrong for doing this, if i could do it myself i would probably do it just as often ;)[/quote]

My good ones? Not much I usually just do a verify on them before doing rebuilds.
My field torque wrenches are really cheap and do tend to drift a bit.

[Steven Cummings]

Thank you for the video Kevin. I am going to consider this for some of my torque wrenches as they are inexpensive (NAPA/O’Reilly brand with my better ones being the Craftsman) as well as I don’t use them enough to justify a professional calibration. Plus as Wysetech pointed out: “Who the hell even knows if their equipment is accurate.”

Now the question: On the clicker type that no longer “click” at the right value (or a barely audible click), would this help that, or is that just the disadvantage of a cheap torque wrench?

[Dave]

Mine looks like the first one but also has a hex screw on the side – it has a clear plastic cap over it.

What is that for?

-Thanks

[Author]

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