Wingnut
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 posted on 7/8/07 at 10:30 PM |
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torque wrench 200 ft/lbs?
Does anyone have some advice or opinions they would be kind enough to share?
I need to torque my front hub nuts to 200 ft/lbs. the only torque wrench I've got goes up to around 100 ft/lbs.
I've been trying to find a suitable wrench to borrow locally (North Devon), but no luck.... so I'm wondering....
If I had a wrench 200ft long on the nut & put a 1lb weight on the other end would that give me 200ft/lbs of torque? or say a 100 ft wrench with a
2lb weight, or a 50 ft wrench with a 4 lb weight & so on & so forth, would a 3 foot spanner with 64 lbs on the end give me 200 ft/lbs of
torque???
does this make sense???
Thanks in advance to anyone who can help!!
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hobbsy
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| posted on 7/8/07 at 10:41 PM |
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Well that appears to be the basic principles of moments and torque etc but I've never tried that practically.
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scottc
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| posted on 7/8/07 at 10:49 PM |
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Basically yes. you are right.
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locogeoff
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| posted on 7/8/07 at 11:24 PM |
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I believe this is what you're after
Torque wrench extension calculator
I would trust Norbar. I used this calculator to do up the hub to strut bolts on my tintop by putting a combination spanner ring end on the desired
nut and then putiing the half inch drive of the torque wrench in the open end and jamming another spanner in the jaws to take up the slack
worked a treat... I'd never seen a 22mm spanner bent like a banana before 
[Edited on 7/8/07 by locogeoff]
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James
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| posted on 8/8/07 at 01:40 AM |
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I'm pretty sure that my Teng torque wrench does 280ft/lb and it only cost about £30-35!
HTH,
James
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"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
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Aboardman
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| posted on 8/8/07 at 06:23 AM |
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halfords do a 225lb torque wrench but costs 59.99.
http://www.halfords.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10151&productId=178621&categoryId=3
1482
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JAG
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| posted on 8/8/07 at 07:47 AM |
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All you have to do is double the length of the wrench you currently own, set it to 100 ftlbs and away you go.
If you have some large diameter tube that would fit over your wrench then your ready to do the job.
[Edited on 8/8/07 by JAG]
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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britishtrident
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| posted on 8/8/07 at 08:13 AM |
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quote:
Originally posted by JAG
All you have to do is double the length of the wrench you currently own, set it to 100 ftlbs and away you go.
If you have some large diameter tube that would fit over your wrench then your ready to do the job.
[Edited on 8/8/07 by JAG]
No that won't work
[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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britishtrident
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| posted on 8/8/07 at 08:16 AM |
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Don't get obsessed with torquing things up.
200 ft/lbs = as tight as you can make it
ie jump on a 4 or 5 foot of scaffolding pole on the end of a 3/4" drive socket breaker bar
[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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scottc
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| posted on 8/8/07 at 09:05 AM |
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quote:
Originally posted by britishtrident
Don't get obsessed with torquing things up.
200 ft/lbs = as tight as you can make it
ie jump on a 4 or 5 foot of scaffolding pole on the end of a 3/4" drive socket breaker bar
exactly. the rear hub nuts on my 24 are supposed to be between 230 lb/ft and 290lb/ft. Thats a bloody huge difference!
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Wingnut
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| posted on 8/8/07 at 09:13 AM |
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Gentlemen,
Thank you all very much for your input! I'm gonna have a look at it again tonight & maybe just try a three foot tube on a ratchet & see
how i get on.
Am very grateful for the info!
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mookaloid
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| posted on 8/8/07 at 10:01 AM |
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quote:
Originally posted by Wingnut
Gentlemen,
Thank you all very much for your input! I'm gonna have a look at it again tonight & maybe just try a three foot tube on a ratchet & see
how i get on.
Am very grateful for the info!
I broke a ratchet doing just that  Use a breaker bar
Cheers
Mark
"That thing you're thinking - it wont be that."
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scottc
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| posted on 8/8/07 at 10:02 AM |
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^+1
That is the easiest way to break a ratchet.
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cadebytiger
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| posted on 8/8/07 at 10:51 AM |
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does a torque wrench on just messure the torque you are applying and by extending the bar do you not just make it easier to achieve the same torque?
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scottc
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| posted on 8/8/07 at 10:55 AM |
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yep. if you set it to 100lb/ft then double the length it will still 'click/ping' at 100lb/ft
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scottc
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| posted on 8/8/07 at 10:56 AM |
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The only accurate way I can think of doing it if your torque wrench doesn't go high enough is with a torque multiplier.
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cadebytiger
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| posted on 8/8/07 at 10:58 AM |
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sounds like a good excuse to get a new tool to me 
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Wingnut
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| posted on 8/8/07 at 11:23 AM |
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quote:
Originally posted by cadebytiger
sounds like a good excuse to get a new tool to me
He hee, good point, well put!
Am I right in thinking you need to extend the ratchet/socket end of the torque wrench, not the handle end.. otherwise you get the same reading as
cadebytiger & scottc say....
The diagram on the norbar website shows the torque wrench extended at the socket end.... (Thanks for that locogeoff)
Regds,
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cadebytiger
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| posted on 8/8/07 at 11:26 AM |
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right yes ic. that would make more sense. lol
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JAG
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| posted on 8/8/07 at 12:30 PM |
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What I wrote will work (although I accept you may break the wrench) check out the Norbar calculator that someone posted a link to 
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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NS Dev
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| posted on 8/8/07 at 12:45 PM |
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no it won't!!!!!
A torque wrench clicks when you apply a load to it, if you put an extension on it then you apply that load with less effort, but the load at the
square drive peg is exactly the same!!!!
I'm afraid some basic mechanics need to be applied here!!!!
Back to the original point, yes you can hang an appropriate weight on a suitable length wrench, and this will almost certainly be more accurate than
many cheaper torque wrenches.
I use exactly this technique for setting the pinion turning torque when putting diffs together.
I have a tool that I have made that bolts to two of the pinion flange bolts, and has a short length of round bar welded to it, who's c of g
applies exactly the correct turning torque.
If you hold the bar up and then let go of it it should very slowly descend. If it doesn't, the bearing preload is too great, if it drops like a
stone, it needs more nip on the bearings.
Bear in mind this is accurate to fractions of 1 NM.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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britishtrident
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| posted on 8/8/07 at 02:14 PM |
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quote:
Originally posted by JAG
What I wrote will work (although I accept you may break the wrench) check out the Norbar calculator that someone posted a link to
Torque wrenches measure torque, doubling the length of the lever will only half the tangential force required to generate the same torque.
Pretty elementary stuff.
[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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rusty nuts
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| posted on 8/8/07 at 06:58 PM |
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quote:
Originally posted by scottc
The only accurate way I can think of doing it if your torque wrench doesn't go high enough is with a torque multiplier.
Cheaper to buy a decent torque wrench in the first place!
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