Another torque wrench thread
 

I've been reading through the countless threads on here about the seemingly limitless options and opinions on torque wrenches.

I'm very much a beginner and am planning on swapping all the components from my current frame to a new frame that I just purchased. I've got Zinn's book and see the charts listed for most all the parts on my bike and from other threads and the interwebs, have found pretty much all necessary torque specs for every piece on my bike. I'd like to do this right and properly torque everything. I don't have any carbon parts, so I could probably get by without, but I'll just feel better knowing that I did things right.

Money is unfortunately a concern and I understand that you get what you pay for. I'm just looking to be a home mechanic who wants to use this project to be able to fix my own bikes if needed. I also plan on doing any work to my wife's road bike and both our mountain bikes. It'll save so much money in the long run if I just learn to do this stuff myself. I really don't see the the torque wrenches being used that often, just this major bike overhaul and then after that, whenever we swap out a component here or there and fixes, etc. No heavy regular use.

From other threads, the discussion tends to range from, "I don't use one, you don't need to either." to "Get cheap ones, they'll work fine." to "Only get a very high quality product or you'll regret it."

I accept that I can't get high end ones and also know that I personally should have at least something around just to be safe. I also gather from previous threads that I would truly want two, one for the low range and one for the high range. So, would the following be fine?

1/4" Harbor Freight Click style - 20-200 In/Lbs. (For stem and low level torques)
http://www.harborfreight.com/cpi/cta...temnumber=2696
$19.99

3/8" Harbor Freight Click style - 0-80 Ft/Lbs. (For crank, bottom bracket, etc. higher level torques)
http://www.harborfreight.com/cpi/cta...Itemnumber=807
$14.99

The prices of those two are insanely low, which makes me feel that the quality might be just as low. It seems too low.

I've also found this beam style from Craftsman at Sears - 0-75 Ft/Lbs.
http://www.sears.com/shc/s/p_10153_1...icationsAnchor
$29.99

Seems in line with the park tool beam style wrenches.

I've seen the Park tool beam styles for around $40 each with their click styles running in the $80 range. I've looked at the click style models ranging from Craftsman to the Home Depot and Lowe's brands ranging from $75 to $120 each. No matter how perfect the real high end stuff is, I'm just not even going to consider looking at models that are hundreds of dollars.

I apologize if I'm beating a dead horse here. There is way too many options out there and I have no idea what is truly necessary for your average home mechanic.

I also don't truly know whether I'd just need beam style or click style. I just got a bike stand and don't feel like I won't be able to see that beam from any angle or position.

Any thoughts would be greatly appreciated. Also, if there are any other decent enough quality, inexpensive torque wrenches out there that I didn't mention, let me know. Thanks.

If you're worried about the angle for using a beam-deflector type wrench, then I think you're right to worry.

The HF click type are allegedly +/- 5%. I'll post some info below to put this in context.

I have a 3/8" Craftsman "Digitork" that was reasonably priced. I use it for the higher torque values and my HF 1/4" for the in-lb stuff. Torque wrenches are notoriously INaccurate at their lower torque ranges.

I'm in the habit of releasing all the spring tension on my TW's after each use. In theory, this helps them stay much more accurate much longer.

The quote:

Quoting from: http://www.unbrako.com/docs/Fastener%20Facts.pdf

METHODS for CONTROLLING TIGHTNESS
Six methods can be used to control tightness of a threaded fastener.
In order of increasing accuracy - and increasing cost - they are:

Method................Accuracy...........Relative Costs
Feel....................+/-35%..............1
Torque wrench......+/-25%..............1-1/2
Turn-of-the-nut....+/-15%..............3
PLI washers..........+/-10%..............7
Bolt elongation.......+/-3-5%............15
Strain gages..........+/-1%.............20

But this table only tells part of the story. The less the accuracy of
the tightening method the greater must be the minimum yield strength
of the fastener in order to compensate for preload variations and to
insure a minimum clamping force. This can be done only be using a
fastener material of greater strength or increasing fastener size -
both of which will increase the cost of the fastener.

The decision as to which tightening method to use depends primarily on
the criticality of the joint. Generally, the more critical the joint
the more need for higher tightening accuracy and the greater the cost
for obtaining the right clamping force. It should always be noted that
the method selected will almost always lie between the two extremes,
for few applications will allow the high inaccuracy of the "feel"
method, while the high cost, highly accurate strain gages are used
almost entirely in the laboratory. The other methods
may be summarized as follows:

TORQUE WRENCH

This is the least expensive of the accepted methods of controlling
fastener preload but is the least accurate, chiefly because the
reading on dial is affected by the friction to be overcome.

TURN-OF-THE-NUT

In this method, the nut or bolt is turned a predetermined number of
degrees after all play has been removed from the joint.
How much to turn the nut or bolt cannot be calculated (because of the
"rubberiness" of the joint) but must be developed by tests for each
joint. It eliminates the friction factor; however, its accuracy is
affected by the care of the workman in measuring the angle the
nut or bolt is turned.

PRELOAD INDICATING WASHERS

Preload indicating (PLI) washers utilize compression of an inner ring
between two flat washers with an outer indicating washer for control.
As the load increases, the inner ring, which is higher than the outer
one, is squeezed down and enlarged in diameter until the
outer washer binds against two flat washers. When the inner ring has
been flattened to this point, the correct clamping force has been
reached. The PLI washer is sensitive only to axial load.

BOLT ELONGATION

In this method, a bolt from the lot is loaded in a tensile machine
with the same nut as used in the application. The distance from the
nut face to the underside of the bolt head is measured, and a plot is
made of bolt elongation in relation to induced load. In the
application, the fastener is tightened and the bolt elongation is
measured until the required preload as determined from the plot has
been achieved.

More general info....

General info on torque, lubrication, and fasteners:

http://www.parktool.com/repair/readhowto.asp?id=88

AND

http://www.parktool.com/repair/readhowto.asp?id=89

AND

http://www.sacskyranch.com/antiseize.htm

AND

http://www.raskcycle.com/techtip/webdoc14.html

The cheap Harbour Freight clicker ones are fine in the small 1/4" inch-lb sizes. They'll easily last you 5-10 years which is all you need.

For the cassette-lockirng and crankarm-bolts, I'd go with the Sears beam-style. There a phenomenon of "creep" in the higher-torque ranges that fool clicker torque-wrenches. What happens is that thread-friction increases more and more as you increase torque and this leads to resistance against the torque-wrench. The clicker type goes off and you think you have the proper torque. But with a beam-type wrench, you'll notice as you reach proper-torque, it drops. You have to continue spinning the wrench an additional 20-45 degrees as the torque-indicator stays on your desired torque. Only after that additional 20-45 degrees has been turned does the indicator stay put and start to increase. On high-torque applications like head-studs, I've found that sometimes you have to turn an additional 90-120 degrees after the initial torque has been reached until it holds.

You want to assume that all torque-specs given are for oiled threads, unless "dry" is specified (rarely).

Finally, there is -- as always -- the Be-All and End-All of torque wrenches.....

http://www.sheldonbrown.com/tork-grip.html

I couldn't think of any angle on a bike that you wouldn't be able to read the torque gauge on a beam style wrench. Also, you will eventually have to have the click-style recalibrated (depending on quality). I would get two a 3/8 and a 1/4 drive, should get all the range you need. Get craftsman, if you have an issue you can just exchange it, I'm using ones from the 50's or 60's and they still work great!

+1

Same for the 3/8".

I have both, though for most of what I use a TW for (BB and cassette) I use an old 1/2" Craftsman clicker. The longer arm makes it easier.

Hey, Neil-

TMI ! :p

Exactly wrong. Torque specifications are given for clean, dry threads unless otherwise specified.

That's true for SAE, DIN, and JIS standards, as well as the aviation industry.

Example: "Be sure the bolt and nut threads are clean and dry, unless otherwise specified by the manufacturer." (FAA AC 43.13-1B, 7-40b)

Remember that your higher-range torque wrench (at least) will be used to apply counter-clockwise torque as well as the normal clockwise torque; some click-style TR's only work for clockwise torque application. Beam-style wrenches do both with aplomb.
The Sears beam-style wrench you mentioned is the one I have. You should easily be able to get at least 10-15% off with all the sales/coupons they have these days. As a bonus, unlike their terrible-quality DigiTork torque wrenches, the beam-style Craftsman has the standard Craftsman hand tool lifetime warranty.

Awesome. Thanks for all the info.

I think I'm going to get the Craftsman beam-style as it's a great price and can handle all the higher torque numbers. I also think I'll get the harbor freight for the lower torques. The prices are right on both of them and I like how the beam style, as mentioned above, can easily work both directions. Plus, I love having any Craftsman tool that has a lifetime warranty.

I have two torque wrenches of the same capacity and quality as the harborfreight ones you are considering. I use them only for occaisional bike maintenance and am fine with them. Since I use them infrequently, I'm happy I didn't drop more cash on something more suited for a pro. For hex sockets I use a 13 piece NEIKO set in the blue case being sold on EBAY. They are metric and the smaller sockets come with 1/4 inch drive and the larger with 3/8 so one set will match your torque wrenches.

LOL!

The clicks/creaks, and torque wrench threads are pretty common.

I like to pepper them with LOTS of information ... for those who later use the search feature.

If I thought there was anything like objective, definitive information on chain maintenance and bike degreasing, I might cut-and-paste that, too.

:)

I agree, if the 43.13 says it, then it's gospel. You happen to be an A & P....?

My harbor freight torque wrench lasted two minutes. The first bolt worked, and it clicked once. The 2nd time it would not click and I snapped a seatpost bolt. I tried it on garage door bolts, auto wheels lugs, etc. It would not click. Worked one time.