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Cusser
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Joined: October 02, 2006
Posts: 31379
Location: Hot Arizona
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VWporscheGT3
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Joined: September 01, 2006
Posts: 2076
Location: Gardnerville, NV
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 Posted: Tue Jul 22, 2014 3:52 pm Post subject: |
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^ this....
have never had a problem with my cheapo's.. the bolt like everyone else is saying is the suspect link in the chain.
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raygreenwood
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Joined: November 24, 2008
Posts: 21520
Location: Oklahoma City
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| Posted: Tue Jul 22, 2014 5:21 pm Post subject: |
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| Anvil wrote: |
| raygreenwood wrote: |
Also.....if you are lazy and do not turn your wrench down to near 0 after each use.....your wrench will be off by an almost guaranteed 10 ft lbs within about a month as the spring takes a set by being under constant load.
This reason combined with # of clicks is why precision industrial users typically just automatically get theirs recalibrated quarterly or less.
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Metals that have a fatigue limit don't "take a set" unless they have been taken past their yield strength. Recalibration requirements are almost always a result of wear within an assembly. IME, with simple beam type torque wrenches, recalibration (outside of normal QC checks) is due to folks using them as breaker bars. |
Dont confuse the issue by mistaking my poor use of words. All springs opetate this way...and yes....simply put when left constantly loaded...they get weak. Yes...fatigue is the incorrect word but the problem is factual.
Having worked for a company at one point that assembled and calibrated their own torque wrenches....I have a pretty good handle on it.
Also being in charge of tooling calibrations at more than a few companies....and having to have thousands of precision tools recal over the years including torque wrenches.....its the springs. Not the detents or pivots or anything else.
And you should know as well that even valve springs change over a long period of time being lect loaded and unused.
Compared to a valve spring, torque wrench springs are fairly delicate.....and.....if you know about torque wrenches....you should have already known this....
What makes the torque wrench spring special is that it must be LINEAR in that any similar encrement of compression will result in uniform change.
This is precisely what gets screwed up by letting the wrench stay set in one loaded position.
Just thought you ought to know.
Ray |
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modok
Samba Member
Joined: October 30, 2009
Posts: 26790
Location: Colorado Springs
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| Posted: Tue Jul 22, 2014 9:30 pm Post subject: |
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| The torque wrenches I use the threads wear, the springs don't change. Your results may vary. |
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Anvil
Samba Member
Joined: September 28, 2009
Posts: 248
Location: Golden, Colorado
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| Posted: Tue Jul 22, 2014 10:34 pm Post subject: |
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| raygreenwood wrote: |
| Anvil wrote: |
| raygreenwood wrote: |
Also.....if you are lazy and do not turn your wrench down to near 0 after each use.....your wrench will be off by an almost guaranteed 10 ft lbs within about a month as the spring takes a set by being under constant load.
This reason combined with # of clicks is why precision industrial users typically just automatically get theirs recalibrated quarterly or less.
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Metals that have a fatigue limit don't "take a set" unless they have been taken past their yield strength. Recalibration requirements are almost always a result of wear within an assembly. IME, with simple beam type torque wrenches, recalibration (outside of normal QC checks) is due to folks using them as breaker bars. |
Dont confuse the issue by mistaking my poor use of words. All springs opetate this way...and yes....simply put when left constantly loaded...they get weak. Yes...fatigue is the incorrect word but the problem is factual.
Having worked for a company at one point that assembled and calibrated their own torque wrenches....I have a pretty good handle on it.
Also being in charge of tooling calibrations at more than a few companies....and having to have thousands of precision tools recal over the years including torque wrenches.....its the springs. Not the detents or pivots or anything else.
And you should know as well that even valve springs change over a long period of time being lect loaded and unused.
Compared to a valve spring, torque wrench springs are fairly delicate.....and.....if you know about torque wrenches....you should have already known this....
What makes the torque wrench spring special is that it must be LINEAR in that any similar encrement of compression will result in uniform change.
This is precisely what gets screwed up by letting the wrench stay set in one loaded position.
Just thought you ought to know.
Ray |
With no disrespect, and without posting my resume, yes, I'm familiar with linear springs, Hooke's Law, and spring relaxation and creep. And I'll repeat that needing to back a torque wrench to zero is a myth. The life cycle of a valve spring with their millions upon millions of cycles in a hot environment, never at zero preload unless you've dropped a valve down a cylinder, and also often left fully compressed, has about as much in common with a torque wrench as it does a paper clip. We'll have to agree to disagree or we'll be here forever. 
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smkn_vw
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Joined: August 22, 2004
Posts: 809
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| Posted: Wed Jul 23, 2014 5:28 am Post subject: |
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| Anvil wrote: |
| And I'll repeat that needing to back a torque wrench to zero is a myth. The life cycle of a valve spring with their millions upon millions of cycles in a hot environment, never at zero preload |
Does the torque wrench you're talking about come with valve guides too? Who you trying to fool come on' dude give it a rest.
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Dale M.
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Joined: April 12, 2006
Posts: 20380
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Wed Jul 23, 2014 7:27 am Post subject: |
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Another thing here that bothers me, is why is not your arm calibrated (just terminology) after a while working on these engines one should get a feel for how tight a bolt should be....
My friend who is great builder can usually get a bolt with in 1-2 ft-lbs just by feel..... Very rarely is he wrong and ... He never breaks a bolt unless its bad....
Trust you muscle feed back more and torque wrench less.....NO I am not saying do not use torque wrench, but use what god gave you too....
Got to wonder how this type of torque wrench can be more accurate when pointer can be almost any place and its user relies on visual interpretation... Haptic feed back (click) or digital numbers has to be more accurate (if calibrated correctly) ...
(beam type torque wrench)
Dale
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Dale M.
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Joined: April 12, 2006
Posts: 20380
Location: Just a tiny bit west of Yosemite Valley
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| Posted: Wed Jul 23, 2014 7:40 am Post subject: |
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| smkn_vw wrote: |
| Anvil wrote: |
| And I'll repeat that needing to back a torque wrench to zero is a myth. The life cycle of a valve spring with their millions upon millions of cycles in a hot environment, never at zero preload |
Does the torque wrench you're talking about come with valve guides too? Who you trying to fool come on' dude give it a rest. |
Little far out there in left field aren't you.... You miss the "springs" part and jumped right to valve guides ... HUH?
Dale
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“Fear The Government That Wants To Take Your Guns" - Thomas Jefferson.
"Kellison Sand Piper Roadster" For Street & Show.
"Joe Pody Sandrover" Buggy with 2180 for Autocross (Sold)
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All suggestions and advice are purely my own opinion. You are free to ignore them if you wish ... |
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smkn_vw
Samba Member
Joined: August 22, 2004
Posts: 809
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| Posted: Wed Jul 23, 2014 8:29 am Post subject: |
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Well, sounds like a special torque wrench never know what's inside maybe self tuning mixture screws too. I think some people get too scientific about things and lose traction to common sense.
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Dauz
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Joined: January 05, 2010
Posts: 1790
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| Posted: Wed Jul 23, 2014 10:44 am Post subject: |
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I once used a cheap torque wrench to tighten a loose nut I found between the steering wheel and the drivers seat. I over torqued it and broke the entire left side off. Now I'm all right.  |
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Boolean
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Joined: January 19, 2012
Posts: 1712
Location: Stockholm
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| Posted: Thu Jul 24, 2014 3:45 am Post subject: |
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A torque wrench is no better than its calibration. If you break bolts with it - it may be a bad bolt (rare), wrong torque, or noncalibrated wrench. Nothing else.
It is pretty easy to clamp it in a vise and hang some weight on the handle. I use a plastic can filled with as much water as I need for the torque in question. Dont forget to compensate for shaft length and weight.
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mark tucker
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Joined: April 08, 2009
Posts: 23937
Location: SHALIMAR ,FLORIDA
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| Posted: Thu Jul 24, 2014 9:01 am Post subject: |
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| Boolean wrote: |
A torque wrench is no better than its calibration. If you break bolts with it - it may be a bad bolt (rare), wrong torque, or noncalibrated wrench. Nothing else.
It is pretty easy to clamp it in a vise and hang some weight on the handle. I use a plastic can filled with as much water as I need for the torque in question. Dont forget to compensate for shaft length and weight. |
there is one thing you forgot...THE USER!!Ive seen many guys that dont know how to use one right.there not jerk wrenches. although many jerks think they are.
my high dollor snapponn tq rench siad not nessarry to return the dial to zero. of corse they like to sell tools and like the service money too. but it is a different type than this cheep shit(cheep shit that was closer then the expensive shit) I was effeuked by mac tools(the local dealer ) on a mac tools torque wrench. that was the last time I let him in the shop. I also baned the matco tool guy from the shop,selling or collecting .I dont do well with liers or thiefs or scamers.it is what it is. |
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Anvil
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Joined: September 28, 2009
Posts: 248
Location: Golden, Colorado
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| Posted: Thu Jul 24, 2014 9:20 am Post subject: |
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"Torque wrenches have moving parts and are affected by corrosion and dirt in the mechanism. They should be kept clean and in a storage box. They should not be dismantled without calibration and adjustment afterwards as dismantling and reassembly will affect the torque values.
Although considered by some to be good practice, extensive testing has clearly shown that unwinding a Norbar torque wrench to its minimum setting, hence relaxing the spring between uses, has no effect upon the wrench calibration.
However, if left for a long period of time without use, it is desirable to reduce the setting to the minimum scale value (often 20% of the maximum). The tool should never be adjusted to zero because this can adversely affect the calibration of the wrench."
http://63.135.113.73/Portals/0/NTTS%20TorquePaper2a%20Nov08%20NAB.pdf
http://www.norbar-usa.com/about-norbar/company-information.aspx
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VWporscheGT3
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Joined: September 01, 2006
Posts: 2076
Location: Gardnerville, NV
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| Posted: Thu Jul 24, 2014 10:58 am Post subject: |
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Anvil, thank you for providing that information, I like the next sentence stating it should never be relaxed to 0, only to say 20% of max torque value. I know that is what they have found with their wrenches , but a good amount of that can be applied to others.
_________________
Schnell, SCHNELL!
I like being wrong, Because, it is another opportunity to learn. If you stop learning from your mistakes than what is the point?
If you have any questions about Forged ICON 4032 VW pistons just shoot me a line. |
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koolkarmakombi
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