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torque wrench inadequecy??


Ferd/289

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I think that picture is either deceptively small or they made a mistake with the numbers. The 3000 lb/ft torque multipliers that I used to calibrate took two people just to lift them. Also in the picture that looked like a one inch drive which would be very short lived at 8000 lb/ft, or maybe the thing is made out supermetalium and that is why it cost so much.

 

Dragonfly

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hey, I forgot about my electronic Kent-Moore Torque Angle Meter which operates as a torque wrench up to 200 pounds which solves my immediate problem.

I tried to sell this item several time but there is not much of a market for it. Chevy techs used them for engine assembly. I thought I would mention this just for TW afficianadoes!

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vw engines are around 240 on a stock, and can be up to 300-350

 

The tool for the job?

A Torque Meister. basically those torque multipliers, but you use it with a torque wrench and do a bit of math to get the total output. it works GREAT on taking of the huge castle nuts on the rear drums. and it makes putting on a flywheel effortless

http://www2.cip1.com/ProductDetails.asp?ProductCode=ACC%2DC10%2D7036

 

doubt it's much good for us Z guys haha. I love it though.

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I used my Kent-Moore Torque angle meter to spec out my two other TW's. Since the electronic TAM is supposedly always adjusted correctly, I used my other TW's on the TAM while it was installed on a vise.

Damn they were both pretty much on the money. However, what I learned from doing this is you really have to finese the readings. IOW, nudging up, lubricating the fastener (if required), will give a more accurate reading.

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I used my Kent-Moore Torque angle meter to spec out my two other TW's. Since the electronic TAM is supposedly always adjusted correctly, I used my other TW's on the TAM while it was installed on a vise.

Damn they were both pretty much on the money. However, what I learned from doing this is you really have to finese the readings. IOW, nudging up, lubricating the fastener (if required), will give a more accurate reading.

 

Are your two torque wrenches "snap" type wrenches? If they are you should prior to checking them against a standard (or in this case your TAM) set them to max torque (150 lb/ft in your case) and pull them untill they snap (break over) a minimum of 6 times. The reason for this is to reduce the potential for frictional binding of the fulcrum/head/pivot inside the wrench. This is only required when calibrating because a typical bolt or nut that you are going to torque will have a range i.e. 140 to 160 lb/ft in which case you set your wrench to 150 lb/ft, if the wrench is off by 6% instead of the 4% that it is supposed to be within then you are still within the spec of the bolt (6% of 150 is 9 so you can be between 141 and 159) but during calibration you can not be beyond 4% or 6 lb/ft at a setting of 150 lb/ft hence the reason for breaking it over 6 times prior to taking a reading.

 

BTW I do this stuff for a living.

 

Dragonfly (the metrologist)

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one tw is a snap type, and one is a beam type. I tested those two againt my tam. I used only 40 lbs since any more would have required a stronger jig.

Hers a question, once tested, is the snap type TW actually adjustable is its needed to do so. If so, how do you do it.

Ferd

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I probably will be embarrassed for asking this question, but it's bothered me for some time now. When I adjust my valves I use a crow's foot open end wrench and my click style TW. This discussion has revived my concerns that I overtightened my values due to the added offset. What is the proper manner to torque the valve nuts?

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I probably will be embarrassed for asking this question, but it's bothered me for some time now. When I adjust my valves I use a crow's foot open end wrench and my click style TW. This discussion has revived my concerns that I overtightened my values due to the added offset. What is the proper manner to torque the valve nuts?

 

The calculator that I linked in post #10 of this thread should take care of that question for you.

 

 

 

Hers a question, once tested, is the snap type TW actually adjustable is its needed to do so. If so, how do you do it.

Ferd

 

Yes it is adjustable and I would highly recomend that you do not try to adjust it. These wrenches have a spring on the inside of the barrel of the wrench as you turn the handle you compress that spring against a fulcrum that sits on a specialy designed base, the fulcrum is pressed into a precisely cut notch in the shaft of the head piece that is inside the handle below the pivot pin that holds the head in the wrench. When the correct amount of force is reached the fulcrum will allow the head to rotate from iits neutral position to the side, it does this with enough force you can hear and feel it "snap" or "click" which is why it is called a snap or click type wrench.

 

The adjustment for this is in the handle, on most (but not all) snap type wrenches there is a metal similar to solder that is melted into the very bottom of the handle to hide and protect the adjusting nut, you have to melt this metal out of the handle, with the handle locked in position break loose the hollow allen head screw, then you tighten or loosen the adjusting screw undernieth it through the hollow portion, lock the set screw back down and test you adjustment, repeat the above procedure untill the wrench is within tolerance then re-melt the metal back into the base of the handle.

 

If anyone tries the above procedure without the proper calibration standards to verify the adjustments made you can safely know that you have turned your torque wrench into a ratchet that makes a loud click every now and then.

 

 

another thought, why is the TAM so 'trustworthy'. Why is it that the electronic device never goes out of adjustment?

 

It's not... it just doesn't have as much exposure to the general public and therefore people do not know as much about it. I can assure you that electronic devices go out of adjustment as well.

 

Dragonfly

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Dragonfly, thanks for the link. You've now put to rest my concern regarding use of a crow's foot wrench / TW combination for adjusting values. Roughly calculated, on a 40 ft pound torque requirement, a 1/2 inch crow's foot extension would increase the actual torque by only 1 foot/pound. Well within the 36 - 43 ft/pd suggested setting for the pivot nut.

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Great information thanks,,

Thanks, no question that all things go out of adjustment. I guess the TAM if not abused should hold onto its caibration ok.

 

My snap type wrench has a small knurled thumb nut at the end of the handle, which I presume is the tightening/loosening of the handle so that once you set it, the handle ( and torque setting ) will not turn while using it.

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The PMEL Schedule on all torque wrenches I used in the USAF was 90 Days or if dropped. You drop it, pack it up and drive it off to PMEL for recalibration.

 

I actually have a Click-Type BEAM torque wrench! It's got an adjustable pointer under the main pointer that allows you to point it to the final torque, and when it deflects that amount the secondary needle trips a device that makes the handle 'click'. Never seen another like it before or since. I picked it up at a garage sale of a Tool and Die man in Pontiac back in the 80's.

 

To go back to multipliers and VW Axle Nuts (And Flywheel Gland Nuts) they actually make low-cost torque multipliers for those applications as well. Basically a torque arm that has a gear that meshes with the flywheel teeth and allows you to put 1/4 the required torque on the drive to completely and fully torque the flywheel gland nut. For the axle nuts they have a punched out gear setup that you bolt to two of the lug bolt holes, and works similarly...

304001.jpg

P1010054.JPG

Pretty Cool, Eh? Cheap as well. It only took 80 years after the application was put into production...

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