Torque Wrench Accuracy

[BMWTurboDzl]

So I'm at it again. With BF around the corner I'm thinking about sneaking in a torque wrench. I'm trying to find an one-size-fits all for things such as spark plugs up to a couple of TTY bolts. So on to my question.

Torque accuracy. Take this example "Torque accuracy of +/- 3% CW between 20% and 100% of wrench capability"


Q: What is the typical accuracy under 20 percent?

I'm asking because I'm having difficulty finding a 3/8" which falls around the 20NM range.

 

[atikovi]

1. What's BF?
2. You don't want to go under 20% if possible, just use a lower capacity wrench.
3. You can use a 1/4" to 3/8" adaptor on a small 1/4" wrench.

 

[FT92]

BF = black friday

 

[The Critic]

Generally speaking, you will need 3 wrenches in your arsenal to cover most needs. Torque wrenches are not accurate under 20% of their range and should not be relied on.

1) An 3/8" inch-lbs wrench for plugs and small bolts (i.e. valve covers, thermostats, etc.)
2) A 3/8" ft lbs wrench for 20-100 ft lbs.
3) A 1/2" torque wrench for 50-250 ft lbs, this can be used for lug nuts, larger suspension bolts and axle nuts.

 

[RooflessVW]

For something like 20nm, a decent 100-1000in-lbs wrench will work. Even if the accuracy drops to +/- 10%, that's still 18-22nm. Close enough.

It's really better to have a range of wrenches.

I have 3 that cover 99% of everything I do professionally and personally.

1/4" 30-200 in-lbs
3/8" 100-1000 in-lbs
1/2" 300-3000 in-lbs

 

[atikovi]

The only place I can think of selling torque wrenches that have Black friday sales is Sears. Where else were you shopping?

 

[BMWTurboDzl]

Thanks gents !

 

[BMWTurboDzl]

Originally Posted by atikovi
The only place I can think of selling torque wrenches that have Black friday sales is Sears. Where else were you shopping?


I was going to look around (Amazon, HF, etc.) The usual suspects.

 

[Gimpy1]

I just picked up a Tekton 1/2 torque wrench and I'm pretty impressed with it its very high qualty, and much better than my old Craftsman one (USA made) . I really can't justify a $300 plus wrench that I rarely use. The accuracy is good for general use and included in the case (which is very nive, hinges are pinned not plastic tabs0 is the calibration card. When I start my next project which will involve removing heads etc, I may get a a CDI ( I think they make them for Snap On) because head bolts are one of those that require the a high level of acc (3% vs 4%). Here is the link if you're interested. It also has a lifetime warranty (does not incl re calibration)

TEKTON 24335 1/2" Drive Click Torque Wrench (10-150'.-Lb./13.6-203.5 Nm)

 

[redbone3]

A typical torque wrench is +/- 4% of setting from 20% to 100% of range. If counterclockwise, make that 6%. The click type torque wrench operate by compressing a spring when you crank on the handle. They can be extremely inaccurate when used below 20% of range. In extreme cases the spring may not even be engaged at very low settings.

 

[928]

You need to be more specific as to your uses- if all your are doing is using the wrench to torque your wheels, a $10- on sale wrench from Harbor Freight will do the job. Watch for sales and remember you can always use your 20% off coupon if not on sale

https://www.harborfreight.com/12-in-drive-click-type-torque-wrench-63882.html

 

[redbone3]

Originally Posted by Gimpy1
I just picked up a Tekton 1/2 torque wrench and I'm pretty impressed with it its very high qualty, and much better than my old Craftsman one (USA made) . I really can't justify a $300 plus wrench that I rarely use. The accuracy is good for general use and included in the case (which is very nive, hinges are pinned not plastic tabs0 is the calibration card. When I start my next project which will involve removing heads etc, I may get a a CDI ( I think they make them for Snap On) because head bolts are one of those that require the a high level of acc (3% vs 4%). Here is the link if you're interested. It also has a lifetime warranty (does not incl re calibration)

TEKTON 24335 1/2" Drive Click Torque Wrench (10-150'.-Lb./13.6-203.5 Nm)


Tekton is a bit misleading about this wrench. I quote from their internet site: Tekton's torque wrenches are each calibrated at three points: 20%, 60%, and 100% of their range. That means that below 20% of range(30 ft. lb) the accuracy is unknown.

 

[supton]

Have you tried the digital calibrator? For a couple years I loved mine. I would position it so that I could read the LCD, then use. No need to set the click setting. Was fast for doing tire rotations. I forget the range but maybe it is accurate enough for the whole range?

[Mine died after a couple of years and I just haven't gotten around to replacing, I liked it but there's been too many other things to get!]

https://www.harborfreight.com/12-in-drive-digital-torque-adapter-63917.html

Hmm, nevermind, says 30 to 147 ft-lbs (40 to 200Nm), probably not the range you need. Maybe below 40 Nm a beam would be better?
https://www.amazon.com/beam-torque-wrench/s?k=beam+torque+wrench