torque wrench question

i was torquing the cam bolts yesterday, using my Craftsman click style wrench. it's only a few years old, hasn't had a lot of use, and i've always dropped the setting down when storing it.

but i wondered about it, and after torquing the bolts to 40 ft. lbs, got out my old beam style wrench and all 3 bolts started to tighten at about 35 ft lbs.

where can i get a torque wrench checked out? i've heard that snap-on trucks have a testing tool on them, is this the case?

i've done the whole bottom end of the engine with this wrench, but now don't want to continue until i know where it's really at.

Maybe read through some old threads...had been asked about before..

http://cse.google.com/cse?cx=partner-pub...&gsc.page=1

thanks, looked at a bunch of these. i've been lazy about using search here, as since the site change here i've not had good results with it. although, google is still the way to go!

I didn't read thru the old thread posted but you torqued it to 40 then if another wrench started to move it at say 45 I'd be OK with that as breakaway torque is gonna be higher but with it turning (earlier) at 35 which is lower than the 40 you left it at then yes I'd want to get some answers. EDIT & the socket etc was all in a straight line especially at the end of the handle arc?

5 pounds isnt much.My Snap on clickers are old one I bought at least 30 years ago the other about 25.Been used more than almost anyones here as I used them daily at work.Had them checked a few times IE recalibrated by the factory.They were never really out.The beam style if like my old old Craftsman thats at least 40 years old will register a bit higher than my clickers.Rocky

Yes it is. When you torque you need to stop as the bolt is moving - that is dynamic torque. When you are checking the torque (bolt6 is not moving)that is static torque which can be 10 to 20% higher than the dynamic torque in my experience.

That means that in order to move a bolt after it has been torqued it can take 10 to 20% more torque to move than it did on the initial torque.

In your case that means you were below 35 lbs if the beam torque wrench is accurate.

I do a lot of work with torquing bolts.........

The lab where I worked does it, but it's in Georgia, unfortunately!

well, at this point, i now know that i need to have both these wrenches checked before i continue with the build.

I have bought three Craftsman clicker torque wrenches. All three have had the nut loosen up in the handle causing the handle to slide. I don't trust them (Craftsman) at all. It is a good idea to have them tested, though.

As others have said, torque on bolt or nut is such an approximate way of estimating clamping force that plus or minus 5 is not something to be overly worried about, especially since just a bit of lubricant on threads can change the reading more than that.

You can use an eight point star socket to directly test one torque wrench against another.

For the cost of a calibration you can buy one of these using a 20% off coupon:

http://t.harborfreight.com/12-in-drive-digital-torque-adapter-68283.html

the one I bought seems within the 2% advertised accuracy, and you can return it if not.

By fixing a torque wrench horizontal in a vise, you can hang vertical weights off the centerpoint of the hand grip and do your own calibration. An accurate "fishermans scale" can also be used instead of weights to pull on the centerpoint of the grip.

360view, unique/innovative info!