torque wrench

[John7]

I aim to do an increasing amount of the maintenance on my current engine (and future one/s) One thing it looks like I will need is a torque wrench. But I am rather confused about them as there are many different types etc.
Any advice or pointers would be gratefully received, I have been told Warren and Brown
Wrenches are good but can’t trace them in the UK

 

[ccscott49]

Most any torque wrench will do for DIY, but teng make a good one, as do snap on, britool the halfords one is also good, any of the good tool shops will no doubt have a range of them, try machine mart aswell, try and get one with a rachet head aswell, handy, 3/8" drive would be adequate, but you want it to fit the socket set you have, I have three, 1/2", 3/8" and 1/32 drive with an adaptor, but you also need to get one which has a torque range, which will suit your engine(s), they make them from baby ones, go humungous! Have a chat with your local mechanic who does your type of engine(s).

 

[tr7v8]

Personally if you are working on car size petrols I'd go for a 3/8th drive and if you work on bigger diesels then go 1/2.
Mine is a Draper and has served me well for years, I've used the Halfords one and it is a very nice torque wrench and if my memory serves me well came top in a test a little while ago in one of the car mags. The Screwfix one was fairly poor from what I remember. I wouldn't spend a fortune on it for amateur use.

Jim
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[nordic_ranger]

LIDL stores were selling a fairlly robust torque wrench recently for £10 Approx can't remember exact price I bought one good value for little money.

 

[nordic_ranger]

LIDL stores were selling a fairlly robust torque wrench recently for £10 Approx can't remember exact price I bought one good value for little money.

 

[mtb]

Well you pay your money and get what you pay for , so hire a good one from a motor factor cos good tools get ruined as soon as you take em to a boat.

I have Snap on 1/4"" drive for out boards and other small kit.
then Britool !/2"" drive which goes up to 120 lbft then the big one still !/2"" drive again brotool up to 160lbft.I could have a tauque converta which was 3/4"" drive but it would have meant big money for stuff to go with it
Dont forget to undo them .
Cheers
Mick

http://homepage.ntlworld.com/boats
I want a steel ex trawler or tug cheap needing work

 

[david_bagshaw]

Before you buy , consult engine mfrs book for the required torque settings, too then buy one of the appropriate values.

then the more you pay the better.

bri´tool do good quaility, snap on etc.

the bending bar type are no where as good in real use on a boat, as one can rarely see the scale properly while pulling, compared to the click type.


David
<A target="_blank" HREF=http://www.euroboating.net>http://www.euroboating.net</A>

 

[oldharry]

Forget about the bending bar type, get a click type which goes well beyond the tightest setting you are going to need. For occasional use a cheaper one is fine, you only need an expensive one if you are going to be using it regularly.

 

[mtb]

Re:well actualy

We carried out a test and the bar type was quite accurate along side a standard type which was surprising .
Mind you I still prefer the ratchet stuff.
Cheers
Mick

http://homepage.ntlworld.com/boats
I want a steel ex trawler or tug cheap needing work

 

[oldharry]

Re:well actualy

Hmm, fine if a) you haven't dropped and bent it, and b) you can actually see the scale clearly. But then the cheaper ratchet type can go off calibration rather easily if abused too, and without telling you its wrong!

Yew pays yer money, yew teks yer choice!

 

[mtb]

Re:well actualy

It's the bending force re the amount of force / length applied so they are useful .
I think the new high tensile bolts that stretch are a B****** cos you cant re use em if you need to , the concept of tighten to a certain torque then turn by degrees , then turn again is by far the best and safest methode .
cheers
Mick

http://homepage.ntlworld.com/boats
I want a steel ex trawler or tug cheap needing work

 

[john_morris_uk]

It depends what sort of torques you are going to need. I have a torque wrench that "clicks" as it gets to the required torque (set by a dial in a window on the side) but it is no good for low torque settings (below about 20 lb/ft). Remember that whatever you end up buying, the setting only will be correct for oiled clean threads and it is usually best to work up to the finished torque setting in several stages.

 

[Chris_Stannard]

Thinking of the cost of your engine and the problems if you get it wrong, I would buy a click wrench, but you do have to get used to them as the click on some is not obvious.

If you are restting the torque on cylinder head nuts, after a top over haul, you set them and then run the engine for about 50 hours and then re-torque them. When you do this it is important to back the nuts off a quarter to half a turn before you torque them as the starting friction is higher than the sliding friction and you will not get the correct reading if you just try to torque them up.

Chris Stannard

 

[mtb]

I say old chap putting oil on the thread gives a false torque figure and should be avoided.

http://homepage.ntlworld.com/boats
I want a steel ex trawler or tug cheap needing work

 

[vyv_cox]

Lubricated threads

This can be a problem area, maybe not for DIY so much but very much so for machinery. Threads oiled from an oil can have a coefficient of friction of somewhere around 0.15 - 0.2. I disagree with mtb, all threads should be lightly oiled for torquing. Unlubricated threads can have a coefficient of over 0.5, so when the torque wrench indicates that the bolt is fully tight it can in fact be undertightened by a considerable margin. This is the best way to get a bolt to fail by fatigue.

At the other end of the scale, Copperslip gives a coefficient of about 0.1 and some of the nickel thread lubricants can be as low as 0.08. So tightening a bolt lubricated with one of these can produce twice the stress in the bolt that was intended.

No wonder that bolt tensioning has taken over as the primary means of tightening in most industrial applications.

 

[ccscott49]

Torque settings for bolts etc are given for DRY threads, ie. no oil on them. If you oil them, you will overtorque them.

 

[tr7v8]

Chris,

a lot of modern type head gaskets specifically state that they aren't to be retorqued. Depends on what the manual says and also which gasket material.
As regards buying the best you can afford I disagree, the test I read basically broke that chain and I think one of the cheaper ones was the most accurate.
Also for average home use they are just overkill.

Jim
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[oldharry]

Re: gaskets and head bolts.

ALWAYS ALWAYS ALWAYS do what the manufaturer says; IF they specify 'oiled threads' for torquing - oil them with engine oil. Otherwise clean them up and fit them dry. If they are to be torqued to a specific setting - do it. If they are to be angle tightened you will start from a specific torque setting anyway and there is no other way of getting it right. Over tightening causes as much damage as under tightening.

Similarly only re-tighten the head bolts if when and how the engine and gasket manufacturers specify. Some types of gasket will fail prematurely if they are released and re tightened, while others will fail if they are not and the only person who knows which is which is the man who designs and makes them.

 

[aztec]

bloody 'ell boys the chap wants a torque wrench.. not an ONC in engineering.

john, go to somewhere like halfords, if you want a cheapie, or to an automotive tool supplier (snap-on, gedore, mac etc) if you'd rether pay more. the break back type are usually better, but it dependes what you're going to use it for.

cylinder head, main and big ends, flywheel and camshaft caps.. important to get perfect.

ancilliaries not so important but if you snap studs it'll cost ya'. the best bet is to acrue knowledge slowly and if in doubt ask, but as you've identified doing the work yourself will give you a better understanding of how the thing works.... and why it sometimes don't!!, (and it can save you some cash) /forums/images/icons/wink.gif

all the best, steve.

 

[mtb]

Re: Lubricated threads

So what happens when the oil is at the bottom of the drilling !!! it hydraulics and gives a false reading.
The best and correct way to make sure the stud or bolt goes in correctely is to clean out the threads on both the stud / bolt and the hole by tap and die .
Cheers
Mick

http://homepage.ntlworld.com/boats
I want a steel ex trawler or tug cheap needing work