• There has been a recent cluster of spammers accessing BARFer accounts and posting spam. To safeguard your account, please consider changing your password. It would be even better to take the additional step of enabling 2 Factor Authentication (2FA) on your BARF account. Read more here.

Torque Wrenches

dravnx said:
You got it or hang a weight off the handle, measure the distance from the center of the drive to where the weight is hung off the handle and do the math. Check at a few points between 20-80%. A torque wrench should never be used outside of this range.
Click to expand...

Or... just completely ignore this. I've been using the same cheap Craftsman clicker torque wrench for the last 18 years and I've never had it calibrated. During that time, I've managed not to break a single fastener nor have one back-out due to being torqued improperly. Most motorcycle maintenance isn't rocket surgery: get the torque value in the ballpark, maybe throw on a dab of Loctite if you're paranoid, and you'll be fine.
 
I would prefer not to rely on luck when my life and limb are at stake. Like I've posted above, one of my duties while in the USAF was calibrating torque wrenches. At least 10% of the wrenches needed adjustment and of those, 1/2 could not be adjusted and were rejected. My own wrenches get cal'd once a year. I've had to have them adjusted and last year one had to sent for repair. The cost for piece of mind is pretty minimal.
It's easy to get a torque wrench off by 10%. "Throw some Loctite on there" and now you're wet torquing the fastener and that's another 20%. You wanna play with 30% on your cam journals? How about that single sided swing arm that is now 50 ftlbs over torqued? Glad the paying public is not relying on your "expertise".
Torque is not about tight but about stretch.
 
rsrider said:
That's a somewhat scary post. The manuals always state how critical the torque values are, and so you go out and get, what you think is the proper tool, and it's really just a matter of hit or miss. :nchantr
Click to expand...

If the manufacturers were that worried about "exact" torque they would provide a proper spec with +/- tolerance values. Not just a single number that doesn't really mean much without a tolerance.

Also, as has been mentioned in this thread, once you start playing with used, somewhat dirty parts any hope of precision is pretty much gone.

Torque wrenches are quite good for making sure a group of bolts have a consistent torque, even if not extremely accurate.

Things with motorcycles are engineered with big safety factors to deal with these issues. Something like a helicopter will have much smaller safety factors that require much more precise work
 
When you see an unusually high torque number in a manual check it with the manufacturer.

In Korea, the manual torque number for the helicopter transmission bolts seemed way to high. We checked with Sikorsky and the manuals were wrong. Every helicopter was grounded and the bolts replaced.
 
bpw said:
If the manufacturers were that worried about "exact" torque they would provide a proper spec with +/- tolerance values. Not just a single number that doesn't really mean much without a tolerance.

Also, as has been mentioned in this thread, once you start playing with used, somewhat dirty parts any hope of precision is pretty much gone.

Torque wrenches are quite good for making sure a group of bolts have a consistent torque, even if not extremely accurate.

Things with motorcycles are engineered with big safety factors to deal with these issues. Something like a helicopter will have much smaller safety factors that require much more precise work
Click to expand...

Nope, your quality torque wrench was built with a tolerance. It was calibrated to within an industry tolerance, the calibration tools was calibrated within a standard (NIST). When manufacturers provide a torque specification (ANSI), this is all taken into account. Think of it as a wedding cake. At the top of the cake is the NIST standard, then the tool calibration tolerance and then the fastener ANSI tolerance at the widest part of the cake. That single number provided by the man'f. is the torque you should use and will fall within the bottom of the cake.
The stretch on a bolt, whether used or new, is always going to be linear. A new bolt stretches the same as a used bolt.

I don't make a habit of installing dirty bolts, do you?
 
Last edited:
dravnx said:
The stretch on a bolt, whether used or new, is always going to be linear. A new bolt stretches the same as a used bolt.
Click to expand...

Agreed on everything you stated, except this.

A torque-to-yield fastener is a one-time use fastener, and a used one will not stretch like a new one, that's why they must be new every time they are installed.
 
brichter said:
Agreed on everything you stated, except this.

A torque-to-yield fastener is a one-time use fastener, and a used one will not stretch like a new one, that's why they must be new every time they are installed.
Click to expand...

I don't think dravnx is talking about only TTY fasteners. TTY fasteners are just torqued/tensioned to or beyond it's Yield Strength. Others remain well within it's elastic range. All fasteners stretch under a load/ tension.

Nerd hat on: All fasteners stretch under tension. Normally they are only tightened to below the Yield strength. The torque spec for most fasteners is to achieve a certain clamping force/ tension(that in turn is proportional to a stretch) and within it's Elastic range usually.. The one time use/ TTY fasteners are just stretched more..
 
RickM said:
I don't think dravnx is talking about only TTY fasteners. TTY fasteners are just torqued/tensioned to or beyond it's Yield Strength. Others remain well within it's elastic range. All fasteners stretch under a load/ tension.

Nerd hat on: All fasteners stretch under tension. Normally they are only tightened to below the Yield strength. The torque spec for most fasteners is to achieve a certain clamping force/ tension(that in turn is proportional to a stretch) and within it's Elastic range usually.. The one time use/ TTY fasteners are just stretched more..
Click to expand...

This.
Thanx
 
anglerdon said:
When you see an unusually high torque number in a manual check it with the manufacturer.

In Korea, the manual torque number for the helicopter transmission bolts seemed way to high. We checked with Sikorsky and the manuals were wrong. Every helicopter was grounded and the bolts replaced.
Click to expand...

My FJR manual calls for 38 inlbs for the oil drain plug. The exact same plug on the final drive is spec'd at 17 inlbs. 38 is wrong for that bolt size. Luckily, while doing my first oil change, I noticed that the 38 seemed unusually high so I checked on the FJR forum and sure enough, it's a known typo.
 
For high torque applications its hard to go wrong with a beam. I also use it to sanity check my other torque wrenches.
 
RickM said:
I don't think dravnx is talking about only TTY fasteners. TTY fasteners are just torqued/tensioned to or beyond it's Yield Strength. Others remain well within it's elastic range. All fasteners stretch under a load/ tension.
Click to expand...

I was clear that he wasn't discussing TTY fasteners, but since this thread is winding up with a decent amount of technical content, they need to be mentioned as well for completeness. :thumbup

I'd hate for someone to read this thread and see the statement "A new bolt stretches the same as a used bolt.", as they're sitting at their monitor (or with their phone in their hand) with a handful of used TTY cylinder head bolts... :nchantr
 
Last edited:
brichter said:
I was clear that he wasn't discussing TTY fasteners, but since this thread is winding up with a decent amount of technical content, they need to be mentioned as well for completeness. :thumbup

I'd hate for someone to read this thread and see the statement "A new bolt stretches the same as a used bolt.", as they're sitting at their monitor (or with their phone in their hand) with a handful of used TTY cylinder head bolts... :nchantr
Click to expand...

:thumbup
 
You know what torque is right?
It's when you wake up with a piss hard on and when you push it down to piss, your heels come off the floor.
I'll probably get banned or something for that one.
 
dravnx said:
You know what torque is right?
It's when you wake up with a piss hard on and when you push it down to piss, your heels come off the floor.
I'll probably get banned or something for that one.
Click to expand...

Fuck you. I don't even remember those days.
 
corndog67 said:
If you don't have one of those load meters, or have access to one real close to where you are working on your stuff (as in checking it every time you use it), you really don't know for sure what you are clicking at.
Click to expand...

Any thoughts on where one might get access to the chingus you refer to in the Bay Area?? I've got a Snap-On electronic torque wrench that I've had for a dozen years. Digital read out, beeps at torque, whatever units you want - love it. Never checked calibration on it, though, and from time to time I do wonder how close it is to accurate. Haven't stripped any bolts out of their alloy holes yet, so it can't be too far off. But still, if I knew where to load test it I'd definitely take it in and check it out.
 
dravnx said:
My FJR manual calls for 38 inlbs for the oil drain plug. The exact same plug on the final drive is spec'd at 17 inlbs. 38 is wrong for that bolt size. Luckily, while doing my first oil change, I noticed that the 38 seemed unusually high so I checked on the FJR forum and sure enough, it's a known typo.
Click to expand...

Too true! Beware if the instructions seem "wrong," they might be wrong. Best to ask a trusted mechanic or do some forum research.

My FJR manual is the same, calling for 43 Nm, 30 ft.lb for an engine oil drain bolt-- which can very well strip the aluminum pan.

Found another error in the FZ-1 manual, which calls for 100 Nm, 72 ft.lb for the six rear sprocket self locking nuts. OH BOY, don't do that.... way too tight.
 
OP, I just sold a Snap On Tech Wrench - pretty awesome wrench.

For my day to day and track use I use a Brownline metal works Digital Torque Wrench:
http://www.brownlinemetalworks.com/torque-wrench

The display is backlit and very easy to read and change between values. It indicates via a Traffic light, instantaneous value and also audible beep.

Apparently they even have an angle adapter upgrade. Pretty awesome setup that can pretty much do anything you ask under $200
 
You must log in or register to reply here.
Back
Top