A few years ago I bought a cheap ($13)(probably chinese) click type torque wrench (Pittsburg brand). I am getting ready to put the head back on my T after some major engine work but I didn't really trust it and thought a calibration test was a good idea.
Here is the wrench:
Here is the test set up: The weight is a battery weighing 36.5 lbs.
And finally the results:
I was amazed. I redid the test several times but the differences were insignificant.
1. Obviously, your results show the wrench to be way better than the cost would suggest.
2. Would you please talk to my wife and explain the value of such activities? Every time I do something similar to your torque wrench test she just can't understand what I'm talking about, much less what I'm doing.
Just tell her to be happy that you have no vices Henry!
I have one exactly like that which I've been using since I started playing around with cars over 25yrs ago. Despite how inexpensive it was and the naughty things I've done with it, it's never let me down.
Cheap tools are OK sometimes.
I'm glad there's people who do things like this
Bud.... I'm assuming harbor freight right?
I got a few Pittsburg adjustable wrenches they seem okay but the medium sized one I was putting quite a bit of pressure on, it slipped sideways and I bent the handle. I know I could have returned it for a new one, but a quick trip to the ol'trusty vice and its good as new.
My next trip to H/F I'll look up a torque wrench...
Years ago I used to do some torque wrench calibration as part of my quality control job. We had certain error allowances (tolerance) that the wrench had to meet. Our standard was a 40 lb weight. And we, as I recall would use the following procedure.
First we'd measure the distance from the middle of the drive to the center of the place where we grabbed the handle. Then we'd set the wrench at whatever we required for torque. We'd slide the weight down the wrench until it clicked. We'd measure from the middle of the drive to the place where that weight was on the handle. Then we'd divide the longest measurement by the shortest and that would give us a test ratio. From there we'd compare our observed test ratio to a table of previously defined test ratios +/- acceptable error.
Taking that one step forward if the end user had known that test ratio and multiplied the required torque by the observed test ratio we could adjust the torque setting on the wrench to assure we got the required torque spec.
Please understand this is something I was involved with 30 years ago and my memory for how I went about doing it might be weak. And it might have been a 45 lb weight or 37.5 lb weight. I just don't recall.
Garnet Bud has a vice --
I can see it in his pictures!
I bought a number of Pittsburgh tools from Harbor Freight as I didn't feel like stocking the county with "good" stuff.......turned out Pittsburgh tools ARE good stuff.......tougher than nails too
I bought a Pittsburgh 1" socket set for the shop too and, naturally, guys wanted to borrow sockets.......grrrrrr........but whatcha gonna do?
None came back broken!
I have one of those Pittsburghs. Owned it for almost 25 years now and it hasn't failed me yet. Originally bought it to torque some rockers on a 69 Firebird 350. (Turns out that unlike Chevy, Poncho 350 rockers aren't torqued...lesson learned but that's another story..)
Oh and I forgot to mention, nice testing, Bud!
Danial, what do you torque Chevy rockers to? Solids or Hydraulics?
Doug, this was 24 years ago. All I remember is taking my 69 Firebird to a buddy's house to do a tune up. He suggested at some point (after many beers) adjusting the rockers. He had a Chiltons that showed only the Chevy spec of "X" foot pounds. Unfortunately, the Pontiac 350 of the same year was adjusted completely differently. Something on the order of, "Seat the nut then back off a 1/4 turn" or some such.
I bought an old Proto torque wrench from a roadside trader in Spokane one trip, the type with the audible click in the handle and the flat bar as the wrench body. I had it tested by the guy who does the annual tests at the local machine shop. He thought it was a great joke, until it tested 0.3% off at 100 foot pounds. He was amazed.
Allan from down under.
We have a 250 ft - lb torque wrench at work that came from Harbor Freight. It has no maker's name, it just has "China" engraved on the side. It has been calibrated every year for the past ten, and always passes under 1% deviation for each increment. It is used hard and continues to provide excellent service.
Chinese can make good stuff. They don't always, but they are perfectly capable of it.
If you look into some past posts that have blasted the Chinese, I have always asked that first one ought to look at the drawing that the part or device was being made to. A manufacturer should only be blamed when the part being manufactured is not made correctly to a known good drawing that was provided to them. I have seen a number of Chinese sourced parts made to USA specs where the parts were perfect and exactly per the drawings. More often a "sample" part is sent to be "knocked off" and the Chinese have reverse engineered the part without any knowledge of what is important nor of the metallurgy of some critical part of the device. That is what more often happens since it is a quick way to make a buck and the source of the sample is the guilty party as far as I am concerned. This is not an attempt to whitewash all parts from China since they have zero regard for intellectual property rights and will copy anything without a moments hesitation and parts made in China to Chinese reverse engineered drawings can result in motors that last for 1 RPM because they thought that an oil lite bronze bearing was simply a brass bushing. They are very aggressive.
One of my dear departed relative's idea of torque was to get it as tight as possible, and then go another half round. I hated for him to help me or get involved, I spent more time drilling out broken studs than working on the project. Most of those old timers were that way, and until you have worked in the oilfield, you don't understand how tight tight is.
In my industry, the overwhelming majority of product from China is crap. Their finished steel products are to be avoided with a wide berth. Have they gotten better over time? Somewhat. Is it product that you want your production facilities to rely on? Not a chance. Particularly the bearings. I wouldn't put a Chinese bearing in a skateboard, let alone in my car or on my sawmill planer.
Steve: yep! It was from a Harbor Freight sale catalog (back when shipping was free!).
Royce: I think you hit it dead on. the chinese can make very good stuff, the problem is, you don't always know until you've used it awhile.
A friend used to say that all chinese tools come with a Georgia warranty. When I asked what that was, he said "If it breaks, you own both pieces!"
I have had china tools in the past and most have failed on first time used.
In this day and age I try to "Buy American" even if it costs a little more.
Problem is... "Made in American" can be very difficult to find.
So would the torque pressure be on head bolts, I can't seem to find it stated any where?
Generally 50 to 55 ft/lb Some go a bit higher but at risk to striped threads in the block.
Make sure the threads and holes in the block are clean and that the bolts won't bottom out before getting properly tightened. One method is to put the head on with no gasket and tighten the bolts by hand to make sure the bolt heads contact the head. If any bottom out in the block, clean the holes of any junk and try again before shortening the bolts. If any bolts need to be shortened it is safer to shorten all the same amount rather than trying to mark or remember which bolt goes in which hole.
For the earlier motors with the poorer metal in the block, some recommend 45 ft*lbs or less.
If the threads have oil or neversieze on them, most would specify even lower values - perhaps 40 ft*lbs.
Do a search on "head bolts torque". Lotsa info.
Jan. 13 issue of Readers Digest just come and has coupon for 1/4, 3/8 and 1/2 drive Pittsburgh Pro torque wrench's for $9.99 each valid through 4/18/2013. Claims accuracy within +/- 4%.
To second Grady's remarks, I used to work with a guy who believed in the "tighten it until its stripped, then back off half a turn" rule. Thanks to him, I got good at installing helicoils.
The trick to retaining accuracy of the click type torque wrench is to always back the setting off to zilch when finished using it. My old 1/2" drive Proto that I bought somewheres around 1960 still checks out at around 1% accuracy across the board.