pdm
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| posted on 12/11/09 at 09:20 PM |
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Torque Wrench and types of sockets
Evening all,
I'm just trying to weigh up what torque wrench to buy and have some questions about what sockets to use.
It seems that most 1/2 drive torque wrenches will go somewhere between 200Nm and 300Nm. This seems like a lot - for instance it took a breaker bar
and an impact socket to undo my crank pulley on my "practice" engine.
So my first question is - is there any reason why I shouldn't buy a 1/2 torque wrench (or even a 3/4) and then buy an impact socket set to go
with it. That would mean any bolts I am torquing up would be done with an impact (surface drive??) socket.
Secondly, would I need to adjust the torque setting to take into account the impact socket - ie. do you get extra torque because the socket grips the
bolt better ?
Finally - I have a very old Halfords 12 sided set, will these be ok for a 3/8 torque wrench say upto 112Nm max ? (Most seem to go to somewhere upto
80Nm except Sealey which is 112Nm.)
Thanks
Paul
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designer
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| posted on 12/11/09 at 09:26 PM |
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Don't try to delve too deep, or get too technical.
Buy a standard, click type, 1/2in wrench, and use with standard sockets.
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Steve G
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| posted on 12/11/09 at 09:31 PM |
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I'd recommend a Halfords Professional 1/2" socket set if you dont have a set already. If you break one they'll replace it under
lifetime guarantee. If you're lucky there'll be someone local with a Trade Card too - so you can get it cheaper!! 
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londonsean69
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| posted on 12/11/09 at 09:52 PM |
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quote:
Originally posted by pdm
Secondly, would I need to adjust the torque setting to take into account the impact socket - ie. do you get extra torque because the socket grips the
bolt better ?
No, the torque applies to the bolt, not the socket.
You can use standard sockets with a torque wrench or a breaker bar. If they let go, they are not going to fly all over the place like they would if
used on an impact wrench
Sean
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skodaman
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| posted on 12/11/09 at 09:52 PM |
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1/2 inch fine for anything unless you're using it on a bike engine where I'd get a smaller one.
Skodaman
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snapper
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| posted on 12/11/09 at 10:02 PM |
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You are applying progressive torque up to a set limit which is very different to trying to undo a stuck nut... so you will be safe as long as your
sockets are not the cheap cheap ones made of butter
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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BenB
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| posted on 12/11/09 at 10:14 PM |
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I wouldn't use an impact set. The ones I've got are slightly oversize to give a little room for the impact bit to work.
I'd use normal sockets. What are you going to need to torque to 300Nm?
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pdm
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| posted on 13/11/09 at 08:08 AM |
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Morning - thanks for the help everyone - looks like I'm better off looking for a good set of 1/2 inch sockets.
BenB - I can't remember exactly what it was but I'm hoping to do a GKD Legend and 300Nn was the highest torque figure in the 3-series
manual.....
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britishtrident
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| posted on 13/11/09 at 08:09 AM |
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The only jobs on which a torque wrench is really critical is tightening down the cylinder head and cam carrier so select a torque wrench with this in
mind.
For 99% of the work you might do on a modern engines car a 3/8" drive torque wrench covers the ground, most 1/2" drive torque wrenches do
not have a torque range suitable for engine cylinder head on modern engines such as the K series, but a 1/2" drive would be ideal for an Xflo
or Pinto
With bolts over 10mm diameter using a torque wrench is not so critical as long they are properly tightened ---- how tight is properly tightened is
something one learns, but for a 10mm bolt a good pull on an standard length socket ratchet is a about right, for 12mm dia bolts a rally hard pull on
a standard socket ratchet, for 14mm a medium pull on a power bar.
[Edited on 13/11/09 by britishtrident]
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will121
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| posted on 13/11/09 at 08:18 AM |
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as said above ive been looking at getting a torque wrench to rebuild my zetec, and think a 3/8 drive will do most if not all jobs, and be short enough
to get in tight spots. cylinder heads with stretch bolts only require a initial low torque setting with a larder 1/2 may not go low enough, with final
tightening being a further angle of turn. things like hub bolts require a high torque setting but ive generally none these upto 'FT'
[Edited on 13/11/09 by will121]
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britishtrident
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| posted on 13/11/09 at 08:20 AM |
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quote:
Originally posted by pdm
Morning - thanks for the help everyone - looks like I'm better off looking for a good set of 1/2 inch sockets.
BenB - I can't remember exactly what it was but I'm hoping to do a GKD Legend and 300Nn was the highest torque figure in the 3-series
manual.....
No you are looking at it the wrong way ---- at 300NM you don't need a torque wrench 300NM is in real terms is a 100 pounds apllied to the
end of a 2foot 6" power bar ----- which is almost as much as you can apply.
You need to worry about the torque applied small diameter bolts.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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pdm
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| posted on 13/11/09 at 08:36 AM |
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Hi
Ok - seems I'm thinking about this too much and 1/2 might be overkill - especially given as I have all the 3/8 sockets I need (I've not
had to buy anything during stripdown apart from the breaker bar for the pulley bolt).
What's the general consensus on things like hubs/suspension/propshafts - do you generally try and borrow what you need as its mostly a one off
job ?
Thanks again for the advice.
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02GF74
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| posted on 13/11/09 at 08:47 AM |
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what you need:
1/2 in socket set - metric and imperial
1/2 in breaker bar
1/2 in torque wrench - most go to 210 lbft - dunno what that is metric.
if you have air powered impact wrench, then set of
1/2 in impact sockets - metric and imperial
if you want to get fancy
then 3/8 in and 1/4 in socket set and 3/8 in troque - this would be used on tiny things like those on motorcycles - for a car you won't need
it.
even more fancy is to get deep socket set in the above sizes.
note that you would not use an impact wrench to torque up bolts since there is no calibration on how many lbfts or Nm they apply - ask anyone who has
ever tried to undo wheel nuts after KwikFit monkey fitted them.
[Edited on 13/11/09 by 02GF74]
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deezee
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| posted on 13/11/09 at 11:25 AM |
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If your not using old car parts, I wouldn't waste your money on imperial sockets. I've not used one on refurbishing my Sierra parts,
building the chassis or rebuilding by engine.
My 1/2" torque wrench is as long as a Machine Mart breaker bar, so why buy both. If your doing engine work you'll also probably need torx
sockets, which are normally 3/4" drive. This can be proper fiddly with a 1/2" torque wrench and an adapter, so I have a smaller
3/4" torque wrench for fiddly engine work.
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londonsean69
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| posted on 13/11/09 at 11:29 AM |
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quote:
Originally posted by deezeeIf your doing engine work you'll also probably need torx sockets, which are normally 3/4" drive.
This can be proper fiddly with a 1/2" torque wrench and an adapter, so I have a smaller 3/4" torque wrench for fiddly engine work.
Don't you mean 3/8"??
Sean
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deezee
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| posted on 13/11/09 at 12:01 PM |
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quote:
Originally posted by londonsean69
Don't you mean 3/8"??
Sean
Yes, Yes I do! 
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jacko
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| posted on 13/11/09 at 12:08 PM |
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Which ever you get remember to release it after use do not leave the spring in tension
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pdm
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| posted on 13/11/09 at 12:58 PM |
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Thanks for your help everyone - plenty of food for thought before I go off to the autojumble this weekend !!
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Bluemoon
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| posted on 13/11/09 at 02:44 PM |
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quote:
Originally posted by deezee
If your not using old car parts, I wouldn't waste your money on imperial sockets. I've not used one on refurbishing my Sierra parts,
building the chassis or rebuilding by engine.
My 1/2" torque wrench is as long as a Machine Mart breaker bar, so why buy both.
You should never use a torque wrench as a breaker bar... It may screw up the calibration, or worse.. Treat it as a high precision measuring
instrument, which is what it is..
1/2" breaker bar and a decent 1/2" meteric socket set (eclipse set in my case) was the best set of tools for dismantling the dooner..
Dan
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Uryen
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| posted on 23/11/09 at 10:18 AM |
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I torqued a bolt to 300Nm this morning. A hub nut on a 7series BMW. I have a 3/4" torque wrench that is only ever used for this job. For
everything else the 1/2" covers it just fine.
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