Torque Wrenches

[Tiggie]

I am a knob. 

 

bet you read this one!!

[Stu]

28 minutes ago, Tiggie said:

I am a knob. 

 

bet you read this one!!

 

Yup I read it  

[Bianco2564]

On 30/10/2022 at 09:28, fastbob said:

A Torque Wrench is a dangerous tool in the wrong hands . Use one on a partially damaged but serviceable thread and it won't be serviceable any more . 

Just trying to understand this thought.

If we have two M10 8.8 grade bolts, both partially damaged but "servicable" threads as you describe. Both threads are free of oil ,grease and dirt. Target torque is 55Nm, typical torque for that size fastener and grade.

Our torque wrench operative comes along and tightens one bolt, reaches 50 Nm and the thread starts to strip, torque wrench doesnt click, he keeps going and the thread goes completly, game over.

Operative B goes to tighten the 2nd bolt without a torque wrench and.....

[Bender]

1 hour ago, Bianco2564 said:

Just trying to understand this thought.

If we have two M10 8.8 grade bolts, both partially damaged but "servicable" threads as you describe. Both threads are free of oil ,grease and dirt. Target torque is 55Nm, typical torque for that size fastener and grade.

Our torque wrench operative comes along and tightens one bolt, reaches 50 Nm and the thread starts to strip, torque wrench doesnt click, he keeps going and the thread goes completly, game over.

Operative B goes to tighten the 2nd bolt without a torque wrench and.....

Your presuming the torque wrench has  been calibrated and certified which very few in domestic/DIY use ever are, I've replaced head studs when they just didn't feel right. 

[billy sugger]

It's not always the thread on the bolt that is at fault. It is very easy to strip the threads out of a aluminum block if you overdo it, and any grease or oil in a blind hole can be compressed to such a degree that it can split the block 

[Bianco2564]

1 hour ago, Bender said:

Your presuming the torque wrench has  been calibrated and certified which very few in domestic/DIY use ever are, I've replaced head studs when they just didn't feel right. 

In our hypothetical situation, its a new or recently calibrated wrench.

[Bender]

1 minute ago, Bianco2564 said:

In our hypothetical situation, its a new or recently calibrated wrench.

Which is highly unlikely  

[Mississippi Bullfrog]

Then operative C comes along with his angle grinder and nicks both the bike and the torque wrench. 

[Gerontious]

32 minutes ago, Mississippi Bullfrog said:

Then operative C comes along with his angle grinder and nicks both the bike and the torque wrench. 

I wouldn’t worry too much about that. It’s broken. And a broken angle grinder just won’t cut it. There’s always an upside to every minor tragedy. Think positive!!

[Tiggie]

Found this on the road outside my house yesterday.

 

I think someone actually should of used a torque wrench!! 

 

 

[Bianco2564]

11 hours ago, Tiggie said:

Found this on the road outside my house yesterday.

 

I think someone actually should of used a torque wrench!! 

 

 

Indeed, the amount of bolts you see laying in the road is quite scary.

[Bender]

11 hours ago, Tiggie said:

Found this on the road outside my house yesterday.

 

I think someone actually should of used a torque wrench!! 

 

 

Prove it came out of something because it wasn't tight, could have dropped off scrap van for all we know, or horse and cart in your neck of the woods, ask dobin next time you see him  

[Mississippi Bullfrog]

15 hours ago, Bianco2564 said:

Indeed, the amount of bolts you see laying in the road is quite scary.

You want to walk around Oulton Park track. One lap and you've got enough bits to build a car. And tools as well. Plenty of those on the outside of the bends. 

[Bender]

32 minutes ago, Mississippi Bullfrog said:

You want to walk around Oulton Park track. One lap and you've got enough bits to build a car. And tools as well. Plenty of those on the outside of the bends. 

I picked up a lovely scrapper from middle of road last week  

[fastbob]

On 06/11/2022 at 14:41, Bianco2564 said:

Just trying to understand this thought.

If we have two M10 8.8 grade bolts, both partially damaged but "servicable" threads as you describe. Both threads are free of oil ,grease and dirt. Target torque is 55Nm, typical torque for that size fastener and grade.

Our torque wrench operative comes along and tightens one bolt, reaches 50 Nm and the thread starts to strip, torque wrench doesnt click, he keeps going and the thread goes completly, game over.

Operative B goes to tighten the 2nd bolt without a torque wrench and.....

He will feel it get exponentially harder to turn but then it will begin to  plateau out , so to speak . That's when you STOP because that's as good as it's ever  going to get . Continue past this point and it will get easier to turn as the thread strips . It's up to the judgment of the individual and the location and function of the bolt as to whether you leave it in place or go for a Helicoil next time around . Also , please bear in mind that this sort of practice is mainly applicable to older bikes that have passed through the hands of a series of DIY " Mechanics " of unknown expertise ..

[Gerontious]

I’ve seen plenty of bikes like that, over the years. Normally accompanying a new biker with little or no experience. These bikes are easy to spot. Look at the bike. Look at and listen to the seller. If they have a garage look at it. I remember one bike in particular. The seller had a garage and on the bench was a box of Helicoil inserts. And if that wasn’t a red flag… I don’t know what is. My mate didn’t buy. He saved a few £100 more and bought a much nicer bike from a chap known to me who was a bit of an obsessive.

[Bianco2564]

On 09/11/2022 at 08:30, fastbob said:

He will feel it get exponentially harder to turn but then it will begin to  plateau out , so to speak . That's when you STOP because that's as good as it's ever  going to get . Continue past this point and it will get easier to turn as the thread strips . It's up to the judgment of the individual and the location and function of the bolt as to whether you leave it in place or go for a Helicoil next time around . Also , please bear in mind that this sort of practice is mainly applicable to older bikes that have passed through the hands of a series of DIY " Mechanics " of unknown expertise ..

Yep, a predictable outcome, its under torqued and the thread is virtually stripped. Ignoring it is to be expected by your diy mechanic, anyone with an ounce of pride in their work would fix it.

 

[Bianco2564]

On 09/11/2022 at 08:30, fastbob said:

Also , please bear in mind that this sort of practice is mainly applicable to older bikes that have passed through the hands of a series of DIY " Mechanics " of unknown expertise ..

Perhaps if all these diy mechanics learnt how to use a torque wrench, there wouldnt be half as many knackered threads?

A typical fastener is tightened to 75% of its yield point ( excepting stretch bolts) so to strip the thread initially they have had to overtightened it by a fair amount.

[fastbob]

16 hours ago, Bianco2564 said:

Perhaps if all these diy mechanics learnt how to use a torque wrench, there wouldnt be half as many knackered threads?

A typical fastener is tightened to 75% of its yield point ( excepting stretch bolts) so to strip the thread initially they have had to overtightened it by a fair amount.

Ah , now that's a good point . If all the correct torque settings had been adhered to from day one of the motorcycle's construction , there wouldn't be any problems at all . Most torque settings are intended to protect threads from OVER tightening . Take the case of camshaft journals that are barely finger tight before the torque wrench goes click .

[Ronnie]

So what torque wrenches would you recommend ? A £600 Snap-on one or an Ebay special for £50 ?    Or would you prefer the old fashioned beam type over the later click type ?   And has anyone had any experience with getting a torque wrench calibrated ?   I'm referring to amateur/ hobby mechanics, not official garages.  I know I used to pay a bloody fortune to have torque wrenches calibrated annually. It was one of the contractual conditions for being an approved service and repair agent for a certain continental moto manufacturer.  I found for the smaller torque wrenches, 1/4 and 3/8 inch drives it was actually cheaper and more convenient to just replace them !

[Gerontious]

Mine are Wera and the cost of recalibration is (or was) about £40 at their service centre near chesterfield.. when I last enquired.

 

if you want a really high quality torque wrench that’s not a norbar. The other brand I would personally recommend at the (sorta) budget end is Teng and higher up the price bracket Hazet (made in Germany) or even higher end Stahlwille. Though they are high end and close to or even above Snap-on. Not really aimed at the home mechanic. Unless you are addicted to extremely well made tools and money isn’t an issue. Buy once - cry once.

 

I think Wera is great. My second choice would be Hazet.

Edited January 3, 2023 by Gerontious

[Bianco2564]

We use a mix of Snap On, Norbar or Gedore torque leader at work.

We have an on-site calibrator so it's easy to check any wrenches but if any are out of calibration they have to go back to their relevant supplier, normally around £80-100 per wrench.

I have used the bendy bar type but didn't like the scale & pointer set up, but that's just personal preference. I guess there is less to go wrong with them.

The dial type (Gedore) are nice, you can see the torque rising so you know if the thread is good and a tell tale indicator to show the max torque.

I have a couple of Snap on wrenches that I've had for years, only used now at home. Took my 3/8 wrench into work and checked its calibration, it was only a couple of Nm out throughout the range, not bad considering its over 30 years old.

If I had to buy one, it would be Norbar, well made, nice to use and reasonably priced. Made in Banbury so easy to get serviced as my work is also in Banbury.

[Gerontious]

I’ve seen multiple reports about Norbar going wildly out of spec and very quickly which is so beyond the pale for an item like this even the “made in Britain badge” is rendered useless, so for that reason I’m not going to recommend them to anyone. I forgot about Gedore another German brand that is well worth considering. On a par with Hazet. Perhaps a little higher up the price ladder.

Edited January 4, 2023 by Gerontious

[Bianco2564]

@Gerontious,That's not our experience, we have about 10 of them of various sizes and find them pretty reliable.

They get calibrated once a year.

[Ronnie]

On 03/01/2023 at 09:36, Gerontious said:

Mine are Wera and the cost of recalibration is (or was) about £40 at their service centre near chesterfield.. when I last enquired.

 

if you want a really high quality torque wrench that’s not a norbar. The other brand I would personally recommend at the (sorta) budget end is Teng and higher up the price bracket Hazet (made in Germany) or even higher end Stahlwille. Though they are high end and close to or even above Snap-on. Not really aimed at the home mechanic. Unless you are addicted to extremely well made tools and money isn’t an issue. Buy once - cry once.

 

I think Wera is great. My second choice would be Hazet.

The official recommendation for us was Hazet for the smaller ones and Stahlwille for the larger ones.  Some of the workshop staff had their own personal Snap-on units but I warned them to make sure the area Service Manager  ( from that certain continental manufacturer...)  never got wind of them.