Proto 6008 torque wrench

[xladkalkd]

Proto 6008 torque wrench ... 5 to 75 ft/lbs .. 3/8 inch drive.

This is an older used torque wrench ...


Calibration should be around +/- 4% ?

Anyone know how to calibrate the handle ... i.e. there is an adjustment screw inside the hole in the handle or the entire handle needs to be dismantled?

 

[Charles (in GA)]

Proto torque wrenches do not, that I recall, have an adjusting screw. Several years ago, the guy in our torque wrench calibration room showed me that the Proto Tq wrenches required that you change the rocking block to adjust the calibration. Apparently Proto makes a zillion different rocking blocks that go between the spring and the ratchet head inside the handle, and if out of calibration, you try a different one. They are machined slightly different, to affect the calibration.

Essentially, only a certified calibration room with the proper equipment and parts should be messing with a Proto torque wrench. All you will do is make it worse most likely.

Charles

 

[xladkalkd]

Proto torque wrenches do not, that I recall, have an adjusting screw. Several years ago, the guy in our torque wrench calibration room showed me that the Proto Tq wrenches required that you change the rocking block to adjust the calibration. Apparently Proto makes a zillion different rocking blocks that go between the spring and the ratchet head inside the handle, and if out of calibration, you try a different one. They are machined slightly different, to affect the calibration.

Essentially, only a certified calibration room with the proper equipment and parts should be messing with a Proto torque wrench. All you will do is make it worse most likely.

Charles

I paid a buck or two for it at a garage sale ... After fixing the ratchet mechanism it does work but is less than accurate, especially at the lower settings. Mechanisms inside of the handle appear to have some surface rust.

When set to 5 ft/lbs the tw clicks @ 3 lbs 7.2 oz.
When set to 10 ft/lbs the tw clicks @ 8 lbs 8.2 oz

Approximate readings taken from the center of hand grip area.

 

[garthg]

I paid a buck or two for it at a garage sale ... After fixing the ratchet mechanism it does work but is less than accurate, especially at the lower settings. Mechanisms inside of the handle appear to have some surface rust.

When set to 5 ft/lbs the tw clicks @ 3 lbs 7.2 oz.
When set to 10 ft/lbs the tw clicks @ 8 lbs 8.2 oz

Approximate readings taken from the center of hand grip area.

It's not guaranteed accurate in the bottom 20% of the scale (15ft-lbs).

Try it at 20 ft-lbs or higher. I'd bet you will see more accuracy.

 

[xladkalkd]

It's not guaranteed accurate in the bottom 20% of the scale (15ft-lbs).

Try it at 20 ft-lbs or higher. I'd bet you will see more accuracy.

There are slight inconsistancies between tests but accuracy seems to increase as expected usiing higher torque settings.

tw setting

~22.75 ft/lbs clicks @ ~23 lbs 7.6 oz.

 

[P_I_Torque]

Proto torque wrenches do not, that I recall, have an adjusting screw. Several years ago, the guy in our torque wrench calibration room showed me that the Proto Tq wrenches required that you change the rocking block to adjust the calibration. Apparently Proto makes a zillion different rocking blocks that go between the spring and the ratchet head inside the handle, and if out of calibration, you try a different one. They are machined slightly different, to affect the calibration.

Essentially, only a certified calibration room with the proper equipment and parts should be messing with a Proto torque wrench. All you will do is make it worse most likely.

Charles

Good answer. The tilt block design. Next time I'm at the MAC / Proto cal lab I'll try and grab a picture. They have an entire cabinet filled with drawers and drawers of blocks and shims (used to get in-between block sizes). 5-75Ft.Lb. is a great range working around the car / truck. However, I do not like that they mark below the 20% of full scale.