Tools & Fabrication - Where do you calibrate TQ wrenches?

I have an Autozone OEM Tq wrench. Its about a year old...Where do you take these things to ensure they are still accurate? I dont want to take any chances when installing my heads.

Thanks,

if you know some one with a snap on torque wrench ,you can test it with that.

I use to sell craftsman tools and they sold calibration units at about 1k a piece I.e 1/4 3/8 and 1/2 were 1k per size. Outside of that.... Good luck! No one does outside of the army or like the one guy said I "think" snap on tests their own wrenches... The company that makes craftsman tq wrenches resides in Georgia, if you figure out who manufactured your wrench they may be able to help.

Here is where I go to get mine done..They are local to me but I am sure you can ship to them and they will ship back..Forty dollars for 150lbs ad Fifty dollars for a wrench up to 250lbs..Plus shipping if not local..

http://www.washingtoncalibration.com

I have one of these. Does not calibrate, but I know where to set torque wrench to get required torque.
http://www.amazon.com/Alltrade-940759-Powerbuilt-Digital-Adaptor/dp/B0031QPJZG

My local snap-on truck checks mine right on the truck .. Has a calibration tool on the truck. We have 12 of them we check about once ever 3 months.