Camshaft Bearing Cap bolt torque

[stephen9666]

Most manufacturers only claim their torque wrenches will be accurate from 20% to 100% of full scale.

For example, here's what Snap-On says:
http://www1.snapon.com/display/901/WWW/Downloads/CatalogPages/CAT1000i_Torque_Tools.pdf
Quote:
All Snap-on® Torque Wrenches, Drivers and Testers are provided with a Certificate of Calibration. All wrenches and drivers are calibrated
per ASME B-107-14 and ISO 6789 Standards for Accuracy, from 20% to 100% of full scale, using NIST traceable equipment.



So, you should be using a torque wrench where your desired torque is between 20% and 100% of the wrench's capacity.

This is why I have 5 torque wrenches, and I'm only a DIY'er. The lower torque wrenches are the ones I use the most. I have a 1/4" drive beam wrench rated up to 100 in lbs, a 50 - 250 in-lbs wrench, a couple 15 - 75 ft-lbs wrenches and a 150 ft-lbs wrench that is mostly used for torquing wheels. There may be one or two more I'm forgetting.

 

[morris]

just torqueing to a spec isnt all there is to bolting something down. you have to feel how tight it is. have you had a bolt failing be for you got spec? couldnt you tell be for it failed?

 

[artbuc]

Originally Posted By: Vikas
Was that 1/2 inch or 3/8 inch? I was not aware of any 1/2 torque wrench having 11 ft-lb marking on it. In general torque wrenches are only to be used between 20%-100% of their scale. What gets confusing is that some manufacturer will "eat" that 20% themselves and will NOT show 0-20%. In that case, manufacturer has already accounted for the inherent inaccuracy at the bottom of the scale by removing the bottom portion of the scale.

Since you actually did the calibration yourself, you are better than the 99% of the users who never bother with that! Please do similar calibration with the new one even if it is a Snap-On!

- Vikas


Please read my post on the Tool forum regarding my new 1/4" wrench. My 1/2" is a vintage Sears Digitork. It's claimed accuracy is +/- 3% above 30 ft-lbs and +/- 1 ft-lb below 30 ft-lbs. Even though this wrench is 30 years old, it is dead on at 75 ft-lbs and, as claimed, off 1 ft-lb at 10 ft-lbs. It has a max capacity of 150 ft-lbs. It has two scales. The ft-lb scale starts at 10 and has 1 ft-lb increments. The nm scale starts at 12 and has 2 nm increments. The click at 10 ft-lbs is easy to hear/feel. The biggest problem doing low torques is its physical size. Having said that, the 1/4" is deluxe doing 12 ft-lbs and 69in-lbs.