Torque Wrench Ignorance / Questions (warning: Long post)

[Marsh White]

Okay, so I'm doing the valves on my FJ (about the 6th time I've done valves on an FJ - so I'm moderately experienced at it).  I end up not placing a shim properly into the bucket fully and not noticing it.  I rotate the crankshaft to go to the next cylinder set.  I feel the resistance in the crankshaft (so I don't actually screw anything up) but the shim is wedged under the cam and bucket and I can't get it out.  So I end up loosening up the cam cap bolts just enough to take the pressure off of the shim and get it out.  Cool!  I put it in and everything is fine!   (I hope)

Now I just need to tighten up the cam cap bolts again.  I pull out my trusty Yamaha Service Manual and see that that they have a torque value of 8.7 ft lbs of torque....hmmm.  I don't actually own a torque wrench.  I could just use my usual "built in approximate right arm torque wrench" like I have been doing for years...or go buy one.  Now I only need to tighten up 9 of the bolts again, but I think maybe it's time to do it properly.  These bolts are putting tension on my exhaust cam after all (my thoughts)...and perhaps if the Yamaha Engineers took the time to actually make it "8.7 ft lbs" then it might be important - or at least important enough that they are all identical in torque values.

So, after realizing that Torque wrenches START at $80.00 and go up from there - I decide to buy a cheap Harbor Freight torque wrench for $15.99.   http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=807
Part of my justification is that I need one that goes from 5 lbs up, and the fact that most of the ones at Home Depot, Lowes, Sears (Craftsman) start at 20 lbs - makes my decision easier.  Now, I already know that the Harbor Freight stuff is generally crap, but it is SOOOO cheap that you figure that if it lasts a year or two before it breaks it is worth the money.

The instructions say that if the tool is NEW or has been sitting for a long time, to run a few "clicks" of it at a low torque setting to move the internal oil a bit and lubricate the gears (or whatever).  I set it to 8.7 ft lbs and decide to test it on my intake cam bolts which have not been touched by me since I've owned my FJ.  First bolt I put it on and apply pressure...."click"...it worked!  Bolt must have been properly tightened already...it did not move at all, and the torque wrench clicked.  This is a good sign!  So I move to the next intake cam bolt....I start turning the bolt slowly...(thinking, odd...maybe this one was loose?)...keep turning...fuck, I'd better stop before I snap the damn bolt!  I think to myself that maybe the threads of that bolt were already screwed up and I didn't know about it.  (this is a self-resetting torque wrench – according to the box and the little manual)   Onto the next bolt...repeat the above scenario...was this one loose too?  Why does it feel like I'm putting a LOT more torque on the wrench than I should be?

I stop and unscrew the bolts;  sure enough, I've stretched them and NEARLY broken them in half.  But I was able to get them out – so that's cool!  I grab a wrench and put it on the end of the torque wrench and try to get it to click with arm strength...no luck...nada.  I take it back to Harbor Freight and get a refund.  It worked ONCE and never again.

I bring a crescent wrench to Harbor Freight and decide to test other units in the store...thinking I must have had a defective unit.  I go through several of them and I can't get ANY of them to click by hand.  I even wedge the crescent wrench against the ground and put at least half of my body weight on it while it is set to 6 or 7 lbs...no luck.  (my hand is getting sore)    I call over the manager of the store...we bring ALL of them (6 or 7 at least) out of the boxes and test.  No luck.  He admits that he (like me) really has no experience with a torque wrench.  We have both read the instructions several times.  We admit we must be idiots – he calls radios for another employee.  Same shit.  The other employee leaves and prints up several pages of instructions for the torque wrench off of the manufacturer's website.  They are the same...just bigger.  We have all read them thoroughly.  It is very simple.  We can't understand how we are so stupid.  We bring out other sizes and models of torque wrenches...we have the same results.  (we have now tested over 10 torque wrenches – and never ONCE got any of them to click).  They say they sell lots of them and get very few returns.  Either the ENTIRE lot is defective – or we are all just stupid.  No conclusion is drawn and I leave.  The torque wrenches are put back on the shelf.

I come home and borrow a torque wrench from a neighbor of mine.  He is a mechanic.  He pulls out two big ass Snap-On brand torque wrenches from his tool boxes.  I can feel the quality of them in my hand.  Nice!  They also both start at 20 or 30 ft lbs.  He finds a smaller one that starts at 10 lbs, but he says you can back it down 10 pounds to essentially zero if needed.  I borrow it.  There is no brand name on it...but he says it has recently been re-calibrated and I believe him – there is a printer type of sticker on it showing the re-calibration.  The quality of it feels like somewhere in-between that of the cheap ass Harbor Freight torque wrenches and the VERY nice Snap-On ones he had.  I bring it over and try another bolt...and I end up stretching the threads on that one too!  No click...nothing.  So, I try my crescent wrench "manual click" trick.  Nothing.

I take it back to him and tell him "Thanks – that did the trick!" – not wanting to admit that I have an ongoing ignorance problem with torque wrenches.

So tell me: what the hell am I doing wrong?  You adjust the setting on the handle, and tighten the lock at the end and that's it right?  I'm trying to be logical about this...but I can't even come up with a plausible theory – other than the fact that I'm simply ignorant.  I even discussed this with Klavdy via Skype video and he pulled out his torque wrench (hey now...keep it down back there...this isn't chat-roulette!!!) and set it to a low torque setting and clicked it with a wrench by hand.  Didn't he?  Is it possible to "click" a torque wrench by hand with a crescent wrench or the like on the end of it by hand?  Someone please help!

[FJSpringy]

I use this style of t/Wrench on the delicate stuff as you can see the bars coming together and the little knob depressing, you set the number you want and push the little rod into the bar, it pops out when you hit the desired number.

 

I also have one of the style you used but I use it for large bolts like rear wheel spindle nuts etc.

[Dan Filetti]

Marsh-

As above, for the less than 20 lbs jobs, I use a non-clicking one sort like the one above -but even less fancy.  Perhaps your issues were that #1. you were using harbor freight crap and #2. you were using a wrench that was ranged down to 10 lbs, and expecting a click looking for 8.5... perhaps it simply does not click below 10.

Anyhow, tools are supposed to make the job easier, not harder...  In a pinch, you can ~ feel 8.5 ft lbs -it's 8.5 pounds 12 inches away from the nut, or 4.25 lbs 24 inches, AKA -not all that much...

Ultimately, there is no substitute for good tools that you know work.

Good luck.

Dan

[fjrpierre]

I tried it with my el cheapo small torque wrench and indeed it does turn by hand with a crescent wrench. Did you make sure that the little flip lever which determines the turn direction (ie clockwise/counterclockwise) is correctly set? I must admit that with small torque values I'm very leery and set it low on initial setting and work my way up if it needs to be precise; I've stripped too many oil drain plugs.

[andyb]

For low values like those a small beam-style torque wrench calibrated to inch-lbs is lovely.  I distrust the click types innately anyhow, as they need periodic service and recalibration, but work well for many folks.

You can always convert between the different force units.  8.7ft/lbs was a conversion, what they really wanted was 12N-m (less likely 1.2kgf-m).

[racerman_27410]

Craftsman does make a click stop torque wrench that goes down to  single digit torque values.... its 3/8ths drive not 1/2" like the bigger ones.

i had it checked and its definitely spot on and not that expensive (for what it does).


http://www.sears.com/shc/s/p_10153_12605_00944593000P?vName=Gifts&cName=Dad&sName=Gadgets%20&%20Tools&psid=FROOGLE01&sid=IDx20070921x00003a



Kookaloo!

Frank

[Coronet]

 You want to stay away from the cheap torque wrenches - only thing they are good for is ---- well hell I can't think of anything they are good for - mabe to use as a hammer. Snap-On does make a torque wrench that goes down low enough to work for what you want. Its a 1/4 inch drive.
I own 3 --- 1/4 - 3/8 and 1/2 inch drive torque wrenches. The 1/4 and 3/8 will cover 99 % of the torque values on your bike. I would not recomend using a 1/2 inch torque wrench on a bike, except mabe for the rear axel bolt.
On a click type torque wrench the farther you get from the midrange settings - going lower, the more likely it is to be off on the torque settings - like using a 1/2 drive click type torque wrench to torque a bolt that has a spec of 18 ft. lbs. not a good idea.
IMO - Its well worth your time to hold off buying that next "gotta have item"  for your bike and getting yourself 1 or 2 good quality torque wrenches --- That is -- If you do most of your own work on your bike.
Mark

[indyblue]

In general, beam type torque wrenches are more accurate and consistent than click type.  As far as I can tell the only advantage the click type has over beam wrenches is that you don't need to be able to read it as you tighten enabling you to do it blind.  I have found very few situations I cannot watch the scale as I work.  I'll take a beam type over the expensive click types needing constant calibration.  Even if you don't drop it or use it often, temperature changes will cause it to eventually need calibration.

I have a K-D 0-60 in-lb for steering box & differential work.:

[mz_rider]

Marsh,

Sorry to hear of your problem. I tend not to use a torque wrench especially for small bolts but if I do I have an ancient "deflecting bar" type. This is 3/8" drive and reads to 50 ft.lb in 5 ft.lb steps. I suppose this type must be inherently accurate.





Stuart (Glasgow, Scotland)

[Dan Filetti]

Stuart and I have exactly the same wrench!

Works like a charm for the small stuff.

sometimes, simpler is better.

Dan

[mz_rider]

Dan,

I "borrowed" the wrench from a friend to fix my first bike 30+ years ago.

Stuart

[jvb_ca]

I have one of the cheaper brand wrenches, and the first thing I did was check to see how accurate it was. Clamped it in the vise and hung my 0-50lb digital fish scale off the end and checked readings at various settings. It was out to lunch at the low and high end, but within reason in the mid ranges. When in doubt I leave it a little loose, as the readings were on the low side. I also have stripped my share of aluminum threads. I actually broke it the other day using it as an breaker bar to get something undone. Now the clicker only works tightening things. I will have to break down and buy a better one. The Sears Craftsmen wrenches look not to bad.

Cheers...Jake

[Ned]

I have the almost identical model to FJspringy only mine is about 40 years old, was pretty expensive at the time and lacks the sophistication of NM and KgM scales - I have to convert everything. I also had a cheap deflection arm type for low settings, up to 20ft.lbs, but discovered that a temperature difference of 10 degrees C made around a 25% difference to the torque result. On a cold day it under-reads and everything ends up overtorqued while the click model is relatively uneffected and when you are looking at sub 10ft.lbs that's bad. I used an old fashioned fish weighing spring scale with the wrench in the vice to check. I occasionally check my big old one the same way - it's how they used to be calibrated before fancy electronics anyway. I prefer the click type especially for awkward places and being a bit long sighted it's hard to read the scale without the magic goggles on. It does need a bit of care like cleaning and lubing but when you think about it, there's not much to go wrong. You do have to remember to push the button in after each measure to reset it but it doesn't rely on the moving parts to actually test the torque. As long as the button is clean and pops out freely and the spring is oiled it works and even if the spring rate is wrong that doesn't alter the reading. I also had an extension arm for the big one that allowed you to double the torque reading.

Ned

[andyb]

Marsh:

Don't feel bad.  I just now ripped a sprocket cover bolt's head off on my zx9.  With a torque wrench.

Meh, I'm gonna call it a weight saving measure and ride it.   

[mst3kguy]

this was a long topic over on the fjr forum list.  from it, i have no faith in torque wrenches.

i had bought one at home depot, it said on the box it had a lifetime warranty.  i open up the box, and in the instructions, it says the warranty is like 90 days or 6 months or a year.  i took it back.

that's all i have to say about that, uh huh.