Inch-Pound Torque Wrenches

[JackIIA]

Is there a difference in measurement sensitivity between a 1/4" and 3/8" beam style torque wrench?

Been reading online that for lower inch-pound stuff (under 50), a 1/4" is better. But with larger nuts on Rovers, I'd rather go with the 3/8". For those that have one, any preference?

[slorocco]

Been working on cars for almost 40 years. Never owned anything but 3/8 and 1/2 drive torque wrenches.

[Terrys]

I think the only reason inch pound wrenches are 1/4" drive is because the whole wrench is smaller and are generally for smaller nuts/bolts/screws. Pretty hard to find a 1/2" drive 5/16" socket.

The drive head itself doesn't have anything to do with the calibration. I have (somone gave it to me, I sure wouldn't go out and buy one) a click type in inch ounces. I keep it in my tool box to impress myself when I need to elevate my self esteem.

[JackIIA]

I'm thinking of instances where inch pounds are low. something like 15 in/lbs. A 3/8" ft/lb wrench will start at 10 ft/lbs. And that would translate to something like 120 inch lbs.

i think i've answered my own question in the interim. 3/8" inch/lb wrenches seem to be 0-600 (but the scales start at 50 - so no good for my needs), whereas 1/4" are 0-60 (better).

[JackIIA]

i need all the self-esteem i can get, from any source available. i'm having trouble with a diff and i want to take an official measurement to see if it's near the 15 inch pounds i've heard should be about right. i could disassemble and use the string method, but i thought i'd go this route.

[bkreutz]

The torque wrench I have dedicated to pinion gear setup is a 0-20 inch pound dial type. It's a Snap On and I've had it since I started working as a mechanic (1967). I'm would think less expensive brands are available. I prefer a dial type for accuracy. (there are other places inch pound wrenches are used, auto transmission valve bodies for one example). Have you checked Sears? They used to carry these.

[Terrys]

I have a dial type that's about 5' long. I borrowed it to set up a Salisbury and the guy told me I could keep it. I think he stole it from Pratt & Whitney when they still made radials in CT. Since that was vack in the 60s, Im guessing it's calibration cert has expired.

[JackIIA]

Yes. I can pick up a beam style one for under $40. I will probably need to go to harbor freight to get a socket adapter to go from 1/4 inch to the 3/4" nut (i think).

[SafeAirOne]

You pretty much answered your own question. Generally, torque wrenches are most accurate toward the middle of their range. Accuracy diminishes on either extreme of the range, but especially on the lower end.

1/4" drive stuff in intended for relatively lower torque applications, while 1/2" and 3/4" drive stuff is designed to really crank on fasteners, so it stands to reason that torque wrench manufacturers will design low torque-range torque wrenches with small drives and high torque-range torque wrenches with larger drives.

From an applied torque standpoint, the smaller wrenches will have finer graduations on the dial than a larger wrenches, allowing greater accuracy during use.

An easy rule to remember: You should select the torque wrench that has your target torque located as close to the center of its range as possible, no matter what the drive size.

[Donnie]

Is there a difference in measurement sensitivity between a 1/4" and 3/8" beam style torque wrench?

Been reading online that for lower inch-pound stuff (under 50), a 1/4" is better. But with larger nuts on Rovers, I'd rather go with the 3/8". For those that have one, any preference?

I don't think that you can find a "beam" 3/8 that will read a scale that low.U can pull 15 inch / pounds with a 6'' wrench & your little finger. I use Snap-on clickers,,3/8 & 1/2..
I am going to be selling a LOT of Snap-on tools in the near future...

[greenmeanie]

Safe air one pretty uch hits it on the head. The center of the tool's range is where it will be most accurate. Tools, however, wear and go out of tune with use and age so accuracy is only guarranteed by regular calibration.

I used to deal with torque wrenches that worked in the inoz range in aerospace but they were calibrated weekly. Rovers don't require that level of accuracy.

[daveb]

If you are trying to set or check the differential pinion bearing pre-load, you need the 1/4" drive beam style torque wrench or dial type. A clicker will not work to measure preload. I bought a Park Tool (bicycle tool company) TW-1 that came with a 1/4" to 3/8" adapter. I think it was just under $30 on ebay.
BTW you need to pull the carrier out to do this check.

[JackIIA]

Thanks Dave. Yes, that's what I'm getting. Didn't know about the middle range point for accuracy, thanks. As for the trick Donnie mentioned, makes me wonder how many other work arounds there are to avoid spending $$. I guess it's one of the benefits of doing this professionally for a couple of decades. Still, my toolbox always likes the new company, even if my wallet doesn't.