REF: Tools - 123

Torque Wrenches

  • Any torque wrench should be regarded as a precision instrument. You are 'trusting' that this tool will work properly whether you are tightening low torque cover bolts or a high torque engine sprocket nut. Do not leave this laying around on the floor or chunked in a tool box unprotected. This will result in it not working properly when you need it to.
    • If it comes with a case when you buy it, keep it in the case when your not using it.
    • If it didn't come with a case, make or buy one.
    • If using the clicker type wrench, always reduce the dial to a low setting when not in use as detailed in the instructions that came with it.
    • If using the beam type wrench, always check and 'zero' the dial if needed before each use.
  • While applying torque, always use slow even motions. Applying torque too fast leads to fooling the torque wrench (and / or your eyes) before torque is actually reached. Establish a pattern to follow every time to condition yourself not to make a mistake when it's counted.
  • The clicker type torque wrench can click too fast or you can end with a temporary visual mistake with a beam wrench 1) 2)
  • The 1/4“ clicker will go way beyond torque when used too fast. By the time you hear the click, your still turning which could result in damaged bolts, bolt heads and even cracking the piece your working on.

Beam Type Torque Wrenches

1/4” Drive - Beam Torque Wrench 3)
Range: 0-80 in/lbs
1/2“ Drive - Beam Torque Wrench 4)
Range: 0-150 ft/lbs
3/4” Drive - Beam Torque Wrench 5)
Range: 0-300 ft/lbs

Attachments / Adapters

Drive Adapters

  • Torque wrenches come with a variety of drive point sizes. Of course, so do sockets. Unless you have a full shop of tools, it can be cost effective to use adapters to give you the flexibility in using the same sockets with different drive wrenches.
  • It's also important at times to be able to get to certain spots with smaller O.D. wrenches with the help from adapters as a (1/4“ drive) 1/2” socket will probably be a smaller outside diameter than 3/8“ or 1/2” drive in the same bolt size.
  • Sometimes, it just all depends on what you have on hand and, if you can adapt to it, that saves you money.
  • In addition certain drive bits (hex / torx etc.), within a kit of them, will have different drive requirements (usually 1/4“ and 3/8” drive internal squares).
  • But, true tool nuts will want to have them all and still need more.
  • You can also 2 adapters back to back to go from 1/2“ to 3/8” and then from 3/8“ to a 1/4” drive socket. There are other combinations as well.
  • If you plan on using a torque wrench, below are some basic size adapters that you'll probably want on hand. So, go ahead and buy them just to have them. You'll appreciate them all eventually…. and probably want more too.

When buying a torque wrench, these are some suggested adapters to have on hand or buy with it:

  • A 1/4“ drive torque wrench may be required for the lower torque bolts (primary, gearcase, derby covers, etc.) which you can buy hex (allen) and star sockets for. However, some are 1/4” and others are 3/8“ drive socket ends. So, you'll need a 1/4” to 3/8“ drive adapter to be able to swap back and forth with these sockets and still use the torque wrench to tighten them properly.
  • A 3/8” drive torque wrench (in some instances) may be useful for both 1/4“ and 1/2” drive sockets so you'll need an adapter up and one down for versatility.
  • A 1/2“ drive torque wrench will probably be too strong to use 1/4” sockets but you'll definitely want to get a 3/8“ adapter in case you need to swap back and forth with 1/2” and 3/8“ drive sockets.
  • A 3/4” drive torque wrench is usually only used in high torque applications and you should only need a 1/2“ drive adapter in it's use.

Socket Extensions

Swivels (or universal joint)

A swivel (or universal joint) is a great little tool for getting into areas where a straight run at a nut / bolt is hindered by obstacles near it (whether by the frame, wheels etc.).

6)

  • But, for the use with a torque wrench, a swivel can be detrimental to achieving even torque. Whether that is a concern to you or your project, you'll have to make that decision. This is just an informative on the subject.
  • With the entire purpose of using a torque wrench being to evenly distribute clamping force throughout the clamped piece and the purpose of a swivel is to allow you get to angled areas of your work piece, these two tools seem to cancel each other (in theory).
  • How much the swivel will change the actual torque on a fastener depends entirely on the angle at which it is used, if the swivel is near the wrench or near the bolt and etc. Any angle different than 90° from the wrench will shorten the distance from the bolt to the wrench. This shorter distance will decrease the amount of actual torque applied the bolt.
  • You wouldn't think that the length of a socket extension between the swivel and the torque wrench would affect actual torque. But the truth is that the longer the extension you use, the more angle you can put on the swivel which does change actual torque at the fastener.
  • A swivel adapter will transmit different amounts of torque and rotation depending on where the two pins are relative to the angle. You can see this for yourself by sticking two extensions into the adapter, bending it about 70 degrees, and slowly rotating the two extensions. With a small angle the error is not too large but as the angle increases the errors increase. 7)
  • With these conditions in mind, swivels have been used with torque wrenches for a very long time. Of course, results will vary and some will say the amount of change in actual torque value at the fastener will be negligible. This is ultimately left up to the end user to decide what is best for them.
Typical application for tightening rocker bolts on an IH engine 'in frame' 8) This is the toughest one to do,
the front right stud on the rear cylinder. 9)

Torque Wrench Extensions (horizontal with the wrench)

  • These are usually considered methods to extend the length of the wrench (in a linear plane) from the drive center to get into confined spaces that the wrench head (or socket) is too big or awkward for. However, for whatever or how you are extending the end of the torque wrench, you'll need to re-calculate the torque setting on the wrench. Extending the end of the wrench (whether with a crows foot, dog bone or other) will add extra leverage (torque) on the nut / bolt so you'll have to lower the setting on the wrench to compensate.
  • Torque is measured at the socket axis. It does not depend on the length of the wrench handle. That only affects the amount of pressure you have to exert to achieve a particular torque.
  • The extension is measured from center axis 10) to the drive (shaft) axis of the torque wrench.
  • The calculation is the same for all types of torque wrenches (whether clicker or beam type). The torque wrench tells you how hard you are pulling at the handle when you back out the ft/lbs, the formula tells you how much torque is on the fastener when you make the wrench show that many ft/lbs. 11)
  • You can search online calculators to find the value to set your torque wrench to achieve actual torque at the fastener.
  • Or, this formula 12) will allow you to achieve (actual) torque on your fastener. M1 = M2 x L1 / L2
    Where:
    • M1 is the torque setting of the wrench
    • M2 is the actual torque applied to the nut
    • L1 is the normal length of the wrench (square drive shank center point to pull handle center point).
    • L2 is the extended length of the wrench (square drive shank center point on wrench to center point of bolt / nut).


Homemade Wrench Extension for in-frame applications 13)
1/2 torque wrench (L) inside a pull handle wrench (minus the handle). 3/4” drive torque wrench (R) with 1/2“ adapter and a socket to fit the
square shank of the 1/2” wrench. You can torque to about 140 foot pounds with this contraption but you have to keep straight alignment with the
2 wrenches or actual torque on the nut will change. This is Not a proper tool setup but it will work with lower torque values. 14)
15)
This application is used to adapt a 1/2“ drive socket for use with a 3/4” drive torque wrench. Really! 16)

Usage / Applying Torque

Proper torque procedures were used to initially build your bike. Skipping any of the advice below should be done at your own risk. Many engine tear-downs are the result of too much torque (or hunkering down) on a nut or bolt. Don't let it be you.

  • Start all of the fasteners in a component before you tighten any of them…not even hand tight. Any misalignment of the part can side load the last fastener enough to prevent it starting or promote cross threading. 17)
  • By hand, all dry bolts should run in rather easily. If not, there may be trash/ debris caught up in the threading (which can alter you reaching proper torque values). Turn all bolts in sequence by hand until snugged.
  • If you're using thread dressing (oil, loctite / anti seize, etc.), these will induce drag on the bolt(s). You can use a socket, without the wrench, to turn the bolts to snug by hand. You will also need to reduce the final torque on your fasteners since thread dressings will add pre-load to the threads. This pre-load is added on top of your final torque. You can use the wet charts below as a guide to decide how to adjust your final torque. This will vary on how much and what type dressing is used on the threads as well as proper use of the torque wrench.
  • Align each bolt chamfer with it's corresponding threaded hole and counter rotate the fastener to the tightening direction a few degrees until you feel the threads “jump”, that indicates the threads are aligned to start in sync.
  • Tighten (to snug) all of the bolts the same way around your piece in a cross pattern to ensure evenness throughout.
  • Find the torque specs for your application and divide that number by three.
  • You now have three different torque values: Unless instructed otherwise by the FSM, start your cross pattern in the center and then move towards the left and then towards the right.
    • First number (lowest number) w / cross pattern over the entire number of fasteners on the piece.
    • Second number repeat the same cross pattern starting with the same bolt you began with on the first pass (all bolts).
    • Final pass (target torque value) repeat the same cross pattern starting with the same bolt you began with on the first pass (all bolts).
  • Lastly, go back around with the final torque to make sure everything is even. At this point, your mainly insuring that you didn't miss a bolt when making the rounds. It's better to know now rather when your on the road.

A Word on Torque and Re-using Damaged Threads

  • There are times when threads are known to be warped / damaged but will be used anyway for different reasons. It is a good idea to reduce the torque used on fasteners in this instance in an effort to save the threads until a proper repair can be made. Thread dressings (anti-seize, Loctite etc.) may help to keep the fastener from walking out due to vibration.
  • Don't make the mistake of over-tightening 18) just to say you are at factory torque spec. You'll have to use your own judgment for how tight is too tight. Sometimes (snug up to “firm plus a little more”) 19) goes a long way.

General Torque Specs

  • Torque specs are usually given in a range (60-70 ft / lbs for example). The fastener should be torqued to the higher figure initially. Then on future torque 'checks', use the lower figure. This allows you to tell if the fastener has maintained needed torque without 'breaking' the bond which keeps it from backing off. 20)
  • In lieu of having torque specs at hand, below are general torque specs for different fasteners. However, nothing takes place of manufacturer torque specs for your specific applications. The torque numbers reflect pressures the bolts can take which doesn't take into account the amount of clamp force for the piece(s) you are clamping (or an aluminum engine). So, it's hard to trust the charts that give a torque values for bolts of a certain size, and then do not specify if the bolt is going into steel or aluminum. With steel bolts going into aluminum (engines), 'ya gotta be careful. 21)
  • Good engineering books, covering fasteners, will describe the situation in full (bolt diameter, thread pitch, bolt coatings, lubrication used etc.). A lot more information than most of us ever use. Also, in the back of some motorcycle manuals you sometimes will find charts listing common bolts and torque settings. Best to take them with a grain of salt, however. 22)
  • When using oiled fasteners, you should take into account the added pre-load from the oil before applying advertised torque to avoid shearing off the bolt head or cracking/ breaking the piece your working on. You can use the Wet Chart below to calculate a torque value with the added pre-load.

Dry Torque Specs ft/lb

  • Convert ft/lb to N*m by multiplying by 1.3558 23)
  • Fastener strength of SAE bolts can be determined by the bolt head grade markings. Unmarked bolt heads are usually mild steel. More grade markings indicate higher strength fasteners. For instance, grade 5 may have three hash marks from the center out to the edge, grade 7 may have five hash marks and grade 8 should have 6 hash marks.24)
  • These are only generalized specs that do not take into account the difference in steel and aluminum threading. See your FSM or instruction manual for specific torque values per application.
Size/Grade1/4“5/16”3/8“7/16”1/2“9/16”5/8“3/4”7/8“1”
SAE 2612203247699615520631025)
SAE 5101933547811415425738258726)
SAE 71325447111015421536057084027)
SAE 81429477811916923038060070028)

Wet Torque Value Chart for Lubed Threads

If bolt threads are lubricated with light oil or anti-seize compound, the torque required to achieve the proper bolt tension is reduced. Below are charts with the proper “wet” torque values for type of bolt used: All charts property of and used by permission from Allied Systems Company.


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Article by Oldrump1 from the XLFORUM http://xlforum.net/forums/showthread.php?t=1959533
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photo by Hippysmack
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Dr Dick
19)
IronMick
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Clymer 2004-2013 HD Sportster Repair Manual
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