torque wreches

[bushwhacker]

Needed a lesson in torque wrenches.

I am almost ready to set the torque for the timing belt tensioner. It says to use a dial type torque wrench and tighten through degree,s ? Way over my head why can the clicky one which I have not be used?

Any help always greatly appreciated.

Thank,s

[Les Henson]

You can buy an angle guage adaptor to fit on a 1/2" drive ratchet. This thing -

http://www.machinemart.co.uk/shop/product/...rque-wrenches-2

Les.

[LandyManLuke]

You need a constant-torque type torque wrench to tension the belt, not an angle gauge.

A 'snap style' torque wrench only tells you the torque once - when it snaps. To tension the belt properly you need to hold that torque/tension whilst you do up the tensioner.

There are two options -

deflection type - cheap, but crude

dial type - more expensive, more accurate

deflection type

dial type

[Mark]

Quick lesson then...

3 types of torque wrench that I know of..

1) Clicky type, clicks at a preset torque - you know about these

2) Angular type:

Where the torque is set as so many NM and then 60 degrees - like TDI head bolts for example.

This is essentially a gauge used with a bar, and you just turn the bolt through the specified number of degrees using the guage.

3) Displacement/bar type wrench:

Where the torque is specified as a figure, usually fairly low, in NM (or mine is in kgm for some reason).

These are useful when you need to hold something at a specified torque while you tighten something else, as is the case with a timing belt - you need to hold the tensioner against the belt with the torque wrench at a certain displacement (identified by the needle) while you tighten up the bolt that holds the tensioner in place.

I hope that helps...

Mark

[bushwhacker]

A BIG BIG THANK,S GUY,S

If I can be of any help this side in NI just ask. Non technical thing,s only mind you.

I owe you

Mark

[Les Henson]

I thought 2 + 3 were the same thing - degrees

Les.

[LandyManLuke]

No, these two measure torque, rather than angular displacement. The scales are marked in Nm / ftlb rather than degrees.

deflection type

dial type

[bushwhacker]

Behave your selves your starting to confuse me.

And just when I tought it was safe to go back out to the garage.

[ciderman]

I use the Deflection type for Timing belts , The draper one shown Is the one I got in Maccess for under a tenner . As mentioned already its not the most accurate but for checking belt tension its fine .

[Les Henson]

I've never used one of those long sticky things

Les.

[LandyManLuke]

I use the Deflection type for Timing belts

Me too, I've got a Franklin one.

At the time i bought that i couldn't afford a dial type. If i needed one now I could hopefully borrow one from work.

[Turbocharger]

[cat among pigeons mode]

As part of what little apprenticeship I served, I remember being rather confused by the following warning:

Calibration may be affected by grip position- always use the handle.

When I got home and did the maths, they're right! The grip position makes a big difference to the deflection and breakover types (ones with a pivot halfway up the handle that "break" into a slight elbow shape at the relevant torque). I suspect that doesn't apply to spring-loaded wrenches that "click" at the torque value you set by turning the end of the handle.

In the past I've had to use a "click" wrench to measure belt tension while someone else does up the tensioner. It's not ideal but you can just about hold it "on the click" while your mate frantically tightens. My theory was that most people are using uncalibrated wrenches anyway so the margin for error must be quite large. Of course, I don't know how many of those belts have failed... Mine's still going but try this at your own risk

[JimAttrill]

The best torque wrenches are those that do not have a scale at all. Like the Britool wrenches that are adjusted with an allen key. They force the use of a test gauge which is hopefully more accurate. Also, once set, the torque does not move. This is very handy in a production environment where the torque wrench is used for one specific purpose.

And, if you are feeling incredibly rich, there are the electronic torque wrenches made by Snap-On and others.

On the cambelt front, I now do mine by feel, having done so many. None have broken (yet )

[steve_a]

Any comments on the electronic ones? My brother is 40 in a week or two and I was thinking an electronic one could be a good present, not something you would necessarily buy yourself.

I know they do a standard torque action, but can you do them in terms of the dial type too, i.e. live LCD display of the current torque value?

ebay torque wrench is one I was thinking of, sealy is namish brand and it is the only ebay offering for a quick check.

[krissvdh]

If you have a friendly local snap on dealer, blue point (Snap on's budget range) have a new set of digital torque wrenches out at the moment. Competitively priced as well, about £85 for a 60nm - 200nm IIRC. I will double check the flyer if i still have it.

[zardos]

I have a snap on digital, very good (ebay example )

Very easy to set, you don't have to un-set it for storage, can measure undo torque but eats batteries (unless you take them out for storage)