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Torque question

Hmmm I dropped back in here tonight. First I want to add in a few things to my previous post. I have never had a T wrench recalibrated, how much does it cost? I can buy them for $30 at Harbor Freight that come with a 4% certificate. I figure the 4% cert is about as trustworthy as my insurance company is (life has variables) so I go with it (and test it to my old needle wrench). If it no longer reads correctly it goes to the scrap metal.
Also just to share, I once tested a bolt on scrap billet just to see when it would fail. It had a spec of 12 to 18 ft lbs. At 30 ft lbs it started to feel weak. At 39 ft lbs the bolt broke. Of course failure would also depend on the material one was working with.
And to Elmosac that wrote
[ I follow what you are saying but don't follow you logic. 100 ft/lbs of torque is just that. It doesn't matter if you use thread tape or pipe dope or nothing. ]

Guy you say that you follow what I am saying but I don't think you do. Let me put it this way. If you run your engine without oil, does the piston still feel the same resistance of the cylinder walls as it does when you add oil ?
The pipe dope is going to lubricate the threads making you (the wrench) feel less resistance (torque) when you turn the bolt to it's internal pressure of thread on thread. But the "internal" pressure of the threads "is" going to be "more" than specs if you keep pulling until you match the physical resistance of if you had not used pipe dope.
 
R_W_B said:
Hmmm I dropped back in here tonight. First I want to add in a few things to my previous post. I have never had a T wrench recalibrated, how much does it cost? I can buy them for $30 at Harbor Freight that come with a 4% certificate. I figure the 4% cert is about as trustworthy as my insurance company is (life has variables) so I go with it (and test it to my old needle wrench). If it no longer reads correctly it goes to the scrap metal.
Also just to share, I once tested a bolt on scrap billet just to see when it would fail. It had a spec of 12 to 18 ft lbs. At 30 ft lbs it started to feel weak. At 39 ft lbs the bolt broke. Of course failure would also depend on the material one was working with.
And to Elmosac that wrote
[ I follow what you are saying but don't follow you logic. 100 ft/lbs of torque is just that. It doesn't matter if you use thread tape or pipe dope or nothing. ]

Guy you say that you follow what I am saying but I don't think you do. Let me put it this way. If you run your engine without oil, does the piston still feel the same resistance of the cylinder walls as it does when you add oil ?
The pipe dope is going to lubricate the threads making you (the wrench) feel less resistance (torque) when you turn the bolt to it's internal pressure of thread on thread. But the "internal" pressure of the threads "is" going to be "more" than specs if you keep pulling until you match the physical resistance of if you had not used pipe dope.
Click to expand...
Depends on the torque wrench as far as calibration, some need to be sent in IE Snap On then wait 7- 10 days to get it back. Some tool outlets have a Torque wrench calibration jig, check your local Napa , and yes lubed threads require a different torque spec than dry, however H D suggests a bit of oil under the head bolts on Evo motors imagine that, Capital Jack
 
[ check your local Napa , and yes lubed threads require a different torque spec than dry, however H D suggests a bit of oil under the head bolts on Evo motors imagine that, Capital Jack ]

Ahh the local Napa, becoming a scarce breed around here. We do still have one though on the other side of town. The discount stores have taken over, AutoZone, Advance Auto etc, course I need to ask since them they may do it too. I might have been throwing away money if they don't charge too much.
Thanks for the tip.

It's possible that is HD's way of stating an increased torque spec for the EVO engines.
 
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This information is posted on most sites explaining torque questions. I will assume is to be factual based on consensus.
 

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Also found this on the net because I know Hd uses that dry patch on alot of fastener kits with original replacement HD parts.

The purpose of lubrication is to ensure that the applied torque deforms the bolt along its axis (stretch) instead of around its diameter (twist). If you've ever had a bolt back off a little when you released the torquing force of a wrench, then there was too much friction between the threads, and the bolt did not receive the intended amount of stretch (spring tension). Lubrication of the bolt threads is important only to ensure that this doesn't occur.

The common standard for thread lubrication is a light coat of oil of about 10W viscosity. A thin coat of most engine oils does just fine. The idea is to allow the threads to move against one another and light oil does that reliably. Of course, this standard assumes that the threads of the bolt and nut, or case, or whatever, have reasonably smooth finishes. Exotic or extreme-pressure lubricants such as gear oils or moly pastes are mostly a waste of time and can actually be harmful if they reduce friction too much.

Then there are the chemicals. Most of us have used Loctite and similar products. Harley relies heavily on such chemicals to maintain the torque of a majority of its fasteners. Those little stripes of paint-like material on your genuine Harley bolt contains micro-balloons filled with a thread locker similar to Loctite (it even may be Loctite, for all I know). When you tighten such a bolt, some of those micro-balloons burst and release the locking compound. As I understand it, this feature is good for four uses, after which you need to replace the bolt or start adding Loctite.
 
Dr.Evil said:
Also found this on the net because I know Hd uses that dry patch on alot of fastener kits with original replacement HD parts.

The purpose of lubrication is to ensure that the applied torque deforms the bolt along its axis (stretch) instead of around its diameter (twist). If you've ever had a bolt back off a little when you released the torquing force of a wrench, then there was too much friction between the threads, and the bolt did not receive the intended amount of stretch (spring tension). Lubrication of the bolt threads is important only to ensure that this doesn't occur.

The common standard for thread lubrication is a light coat of oil of about 10W viscosity. A thin coat of most engine oils does just fine. The idea is to allow the threads to move against one another and light oil does that reliably. Of course, this standard assumes that the threads of the bolt and nut, or case, or whatever, have reasonably smooth finishes. Exotic or extreme-pressure lubricants such as gear oils or moly pastes are mostly a waste of time and can actually be harmful if they reduce friction too much.

Then there are the chemicals. Most of us have used Loctite and similar products. Harley relies heavily on such chemicals to maintain the torque of a majority of its fasteners. Those little stripes of paint-like material on your genuine Harley bolt contains micro-balloons filled with a thread locker similar to Loctite (it even may be Loctite, for all I know). When you tighten such a bolt, some of those micro-balloons burst and release the locking compound. As I understand it, this feature is good for four uses, after which you need to replace the bolt or start adding Loctite.
Click to expand...

I agree with this. The reason for lubricating threads of bolts is to ensure you are getting a true torque on the bolt. When the threads are too dry or not clean, or both, it adds extra resistance too the threads which can lead to inaccurate torque applied to the bolt. I am an auto tech and it is most common to see the service manual require the threads to be lubricated on head bolts or other internal bolts. Not typically necessary on intake manifold or exhaust bolts for example. It is also not recommended on lug nuts. I have seen properly torqued lug nuts come loose because an anti seize lubricant was used on them, I have also seen them loosen because they were overtightened and the threads were stretched too much and then could not hold proper torque any longer. When it comes down to it, there are situations on a bike or car that you can use your discretion on whether or not "tight enough" is acceptable but bolts do have torque specs for a reason and should be used. After a while you may have a "calibrated hand" and can have a rough idea if a bolt is tightened properly or close to properly.
 
R_W_B said:
Well I don't doubt your word, but I would think the torque wrench needs recalibrated or a new one bought if it doesn't click (or read) what it should no matter what size drive or length the wrench is. Foot lbs of force is what it is, if a wrench doesn't respond the set ft. lbs (or inch lbs) then it is useless.
Or are you saying to make sure you get a wrench within the torque "range" of the specs ? If so then yes I totally agree that would be necessary.
Additionally some click type torque wrenches I have used are of the cheaper version, some worked good others were a little off. I tend to always test them with the "physical needle type" before doing anything important. The reason I don't use needle types all the time is they are hard to read upside down and sideways.
Click to expand...

Being an aircraft mechanic also, I can tell you that in the aircraft business, a torque wrench is supposed to be recalibrated and re-certified every 90 days. It tells me that torque wrenches are a ballpark thing if not re-done regularly.
 
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