The Beginners Guide to Torque Wrenches

[scotsbikester]

For me it's very very simple - I know me, I know how I work & I know what I do - I damage things.

I've broken things numerous times on the car through overtightening.
I've flooded the living room twice through overtightening.
I broke a mount for the Wahoo last week through overtightening.

There's a reason for it. I tighten it up and then (especially in the case of the radiator), I think that's probably not enough, I'll give it a bit more, then I think the same again, then I think what if it still works loose/leaks, I'll give it that 'just nip' that everyone loves to talk about.

*snap/bend/crack*

It's all well & good saying don't keep doing it up but what if what I've done isn't enough anyway.

So yeah, it's basically got to the point where if someone has put a torque setting on it then that's what I'll do it to, then I know it's right.

Even if the torque wrench is out a bit, it's still likely to be a better approach than MY 'just nip'

And thanks for the tip in the latter part of your post.

Yes, excellent self knowledge.

I'm the same. Unless I know what 30Nm "feels" like, how do I know when to stop? I don't always use a torque wrench. Until I got my beam wrench I had no way of torquing left hand threads. But at least I would have just done a right hand one on the opposite side (BB, pedal), so had a reference for "feel".

I've done all my own plumbing for several years now, including complete bathroom and kitchen refits, plus various rads. I have a dread of flooding the house, obviously, so avoid compression joints like the plague, if at all possible.

I've learnt a few lessons - 22mm copper is almost the same as old 3/4" imperial. That was a time when my perfectionism paid off. I wasn't 100% happy with a soldered joint I'd made, and a helpful chap at a plumbers merchant suggested - "it's not old 3/4" you're joining to is it? How old's the house?" That was a joint between kitchen ceiling and bathroom floor. I'm fairly sure it would have leaked/flooded eventually, but maybe only after the ceiling was up and plastered.

Compression joints? You just have to be patient, grasshopper. Tighten so it leaks very slightly. Tighten a bit more till it stops That's almost certainly enough. And on rads you can keep inspecting. It helps if you haven't got a floor covering that will get damaged by a small leak. Otherwise the old towels come into use.

Where compression joints scare me is on cold supply. CH isn't at very high pressure, but our mains pressure is 5 bar, and we've got "fast" taps - quarter turn or lever action in the kitchen. I tell the family not to turn cold off too quickly, but I'm not sure everybody (including me) remembers.

 

[Pedropete]

I use Norbar wrenches: SL0 for 4-20 range and TTi50 for 10-50. Also got their TTs driver for 1.5-6.0 (cleats, stems, saddles etc.). They're good quality, not too expensive if you shop around (relative, but I use them a lot on high-end builds and services) and easy to use. The SL0 has more engagement points so can be useful for mid-range applications where space is tight. Worth noting that accuracy on all of them falls off at outer ends of the rated range so having a few is helpful if you use them a lot.

Also got some older cam-over style Britool wrenches; inherited from my dad (aircraft engineer) and at last check they were still accurate so speaks to the quality. The rubbish thrown around about 'zeroing' is exactly that, just wind them back to the lowest marked setting, no lower. Also, always adjust up to your setting, not down from a higher one, don't drop them and definitely keep them dry.

Some of the cheaper wrenches are reasonably usable but I've seen a few where the setting graduations are subject to parallax error, meaning the setting can 1-2 N.m either side of the objective, so be careful. If buying on a budget then consider beam types like the old Parks or even Decathlon's version (if you can still get it) - just don't knock 'em around! I also like some of the newer compact deflection styles with the rotary indicator (Lezyne, Feedback etc.) as they're compact, accurate enough and reasonably tough if you store them in the supplied case. Don't just stuff 'em loose in a saddle pack though as the accuracy won't last long if they get bashed around too much.

 

[wafter]

Diving right in here without reading every single preceding post..

Torque wrenches will be available in a number of formats that suit the torque range they're designed to apply. You'll find:

- Torque screwdrivers for typically low torques - maybe 0-5Nm
- 1/4" (square drive) wrenches, maybe 0-20Nm
- 3/8" (square drive) wrenches, maybe 10-60Nm
- 1/2" (square drive) wrenches, maybe 20-120Nm

Typically 1/4 and 3/8" wrenches are good for the torques required for bike applications. You'll want a set of drivers to suit the fixings on bikes; which are typically 4, 5 and 6mm hex. For 1/4" drive wrenches you can use an appropriate 1/4" hex drive socket with the necessary 1/4" drive hex metric bits. For a 3/4" wrench you can use appropriate 3/8" hex drivers.

FWIW I have a couple of Norbar torque wrenches inherited from my late father, but any decent brand will do but I'd advise you avoid the really cheap cack. Sealey seem to be a reasonable bet.

If any of this is confusing let me know and I'll expand.

HTH

 

[keithmac]

Yes, excellent self knowledge.

I'm the same. Unless I know what 30Nm "feels" like, how do I know when to stop? I don't always use a torque wrench. Until I got my beam wrench I had no way of torquing left hand threads. But at least I would have just done a right hand one on the opposite side (BB, pedal), so had a reference for "feel".

I've done all my own plumbing for several years now, including complete bathroom and kitchen refits, plus various rads. I have a dread of flooding the house, obviously, so avoid compression joints like the plague, if at all possible.

I've learnt a few lessons - 22mm copper is almost the same as old 3/4" imperial. That was a time when my perfectionism paid off. I wasn't 100% happy with a soldered joint I'd made, and a helpful chap at a plumbers merchant suggested - "it's not old 3/4" you're joining to is it? How old's the house?" That was a joint between kitchen ceiling and bathroom floor. I'm fairly sure it would have leaked/flooded eventually, but maybe only after the ceiling was up and plastered.

Compression joints? You just have to be patient, grasshopper. Tighten so it leaks very slightly. Tighten a bit more till it stops That's almost certainly enough. And on rads you can keep inspecting. It helps if you haven't got a floor covering that will get damaged by a small leak. Otherwise the old towels come into use.

Where compression joints scare me is on cold supply. CH isn't at very high pressure, but our mains pressure is 5 bar, and we've got "fast" taps - quarter turn or lever action in the kitchen. I tell the family not to turn cold off too quickly, but I'm not sure everybody (including me) remembers.

You can buy Water Hammer Arrestors, I plan on fitting one to our cold supply.

Never had a Compression Joint fail, I had some copper pipe and fittings bought 15 years ago and the pipe is much thicker and the joints better made than the crap they churn out nowadays.

Decent quality Flex hoses are a must if you have to fit any.

 

[Jody]

I have never felt the need for one in a cycle application, motor vehicles well yes if rebuilding an engine/gearboxes, having worked in a mechanical environment all my life you “get the feel” on how tight to take it, be it on steel or alloys.

lol

The face you pull just before the threads strip

 

[cougie uk]

I have never felt the need for one in a cycle application, motor vehicles well yes if rebuilding an engine/gearboxes, having worked in a mechanical environment all my life you “get the feel” on how tight to take it, be it on steel or alloys.

Yeah me neither.
Until I noticed a stray half Bolt on the garage floor last week and traced it to my stem. As soon as I loosened another bolt then a second bolt snapped.
Replaced the stem and used the px torque wrench on all the bolts. Maybe I have lost my touch or maybe they're using lightweight bolts.

 

[Two-Wheels]

I've learnt a few lessons - 22mm copper is almost the same as old 3/4" imperial.

I don't know whether the emergency plumber we called out was being polite or what, but he said our pipes are pretty easy to get a leak on & that people are calling him out "all the time" because they've smacked them with the hoover or whatever

As ours are 10mm copper pipes.

Typical. Nothing in this flipping house is to our advantage/benefit. It's all a test. lol.

 

[Profpointy]

I've learnt a few lessons - 22mm copper is almost the same as old 3/4" imperial. That was a time when my perfectionism paid off. I wasn't 100% happy with a soldered joint I'd made, and a helpful chap at a plumbers merchant suggested - "it's not old 3/4" you're joining to is it?

I once, successfully I might add, soldered a 1/2" pipe to a 3/4" pipe ! I just gradually built up enough solder to fill the 1/8" gap all round. It didn't leak either. I was quite surprised it worked to be honest but it was worth a go to fix a burst pipe. Can't now quite remember the reason - maybe the joining piece had itself split, but there was a reason. This is not to recommend it as good practice