Torque Wrench

[Stone]

Can anyone recommend an appropriate torque wrench for reg repair. The guy who has overhauled my regs in the past (and he does a fine job) doesn't use one (claims his wrist is calibrated).

As a neophyte reg-tech, I'd like to use the right tool for the job (at least until my wrist gets calibrated). If it matters, I'll be overhauling ScubaPro, Sherwood, and Genesis.

Thanks!

 

[The Chairman]

Those of us involved in the URT (Use the Right Tool) movement have a list of preferred providers. First however, we need to know the range of the torques you will be requiring.

If it is in the range of 30 lb/ft or more any torque wrench will suffice, including craftsman etc. You will probably find the "click" style (or torque limiting) to be the most accurate.

Less than this, and I reccomend that you find a Snap On dealer and find what you need. You can still use a "click" style until you get into the inch/pound range, where a yeild or beam style torque wrench is preferred. The lower the torque needed the more precise the tool has to be. There are some excellent click style that are used for adjusting the bands on transmissions.

While I do not believe in the calibrated wrist, I also do not feel that most tightening specs on a regulator require a torque wrench. As a general rule anything that specifies 15-18 ft/lbs is just normal "wrench-tight". Usually this means that the part in question needs to be tightened in a normal manner. A torque wrench would prabably be overkill. Significantly lower or higher than this merits the use of a torque wrench.

Remember, torques are usually specified to aid in sealing or retention (higher than normal), provide a certain tension or preload (lower than normal) or to protect fragile threads or parts (lower than normal). A quick perusal of my Vance Harlow's Regulator maintenance and repair, reveals that there are not many fasteners that need to be torqued. But where it is needed, you are right to NOT use the calibrated wrist method.

 

[The Chairman]

I own 6 different torque wrenches. the capacities are as follows...

100- 450 ft/lbs "click" (Snap-On)
50-250 ft/Lbs "click" (Snap-On)
20-100 ft/lbs "click" (Snap-On)
20-150 ft/lbs "click (Mac)
5-80 in/lbs "click" (Snap-On)
0-200 in/lbs "beam" (Matco)

Most click style torque wrenches that rely on springs should be calibrated periodically. The beam and the styles and the 2nd and 3rd Snap On wrenches do not. Return any click style torque wrench to "0" between uses to help keep it in calibration. I also own one torque screwdriver that is measured in in/ounces. It is used to adjust relays.

 

[Stone]

Thanks for the 'put, Pete.

Since I don't have the reg specs yet, I can't tell what torque range is required. My gut feel is 20-100 ft-lbs is plenty.

As always, I'm hoping for the definitive recommendation:

"I only use the "Titty-Twister 2000" because it comes with every open end/socket - metric/SAE attachment known to man, and it only costs $1.95 ($2.00 if you want the life-time warranty).

 

[The Chairman]

From what Vance Harlow's manual is showing me, the beam style that is in the 0-200 in/lb range looks like the ticket for you. That being said, I don't think anyone could ever have too many torque wrenches.

 

[Stone]

Did I say ft-lbs. . . I meant furlong-tons!

 

[neil]

Don't forget that most of your work will be done with crow's feet, not regular sockets. So you'll need the following URT formula:

T1=T2 x L1/L2
where
T1 = torque setting (reading) of the wrench
T2 = actual torque applied (torque needed)
L1 = original length of wrench
L2 = extended length of wrench with crow's foot

Of course you would learn this in any URT fundamentals class

Neil

 

[The Chairman]

Also you must have the correct "attitude" when you torque. Odd angles are a "no no" :nono: . Be careful with the placement of your hands, and make sure the handle (if a pivot type) is applying pressure ONLY through the pivot. As a general rule on a click style wrench, the lower the torque, the fainter the click. So be careful lest you torque something off!

 

[Stone]

Vance Harlow seems to be a fan of torque wrenches, and mentions that even experienced techs tend to over-tighten.

Am I wrong in assuming that there should be a torque wrench available that maintains the same lever arm length whether you use sockets or crow's feet? (Or is a crow's foot, by definition, an open ended wrench that fits over the drive end of the torque wrench thereby increasing the length of the lever arm?)

Finally,

If I get my wife to tighten my fittings will I have a "Torque Wench"?

 

[The Chairman]

available that will keep the moment of inertia constant. These only come in a few sizes since they are used for automotive sensors that have wires attached (Oxy sensors, Oil pressure sensors, water temp sensors, knock sensors... you get the picture). I have these hallowed out "sockets" in 1/2", 9/16" 3/4", 1", 1 1/16" and 1 1/4"... I might even have an 1 1/8", but I can't find it.