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+--- Thread: Torque for axle banjo and torque tube bolts (/showthread.php?tid=351)
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Torque for axle banjo and torque tube bolts - Dennis Nicholas - 19-10-2017
Axle =1938/39 (heavy). Bolts = Stainless (A2 - 70) 5/16 BSF cut to length so full thread engagement in banjo halves and torque tube to banjo without bottoming. Using NORD-LOCK lock washers. Threads smeared with copaslip to avoid axle thread corrosion and galling of stainless thread with steel casing.
What is a good torque wrench setting to use?? I have seen that 22Nm (16.2 ftlbs) is max for the 5/16 A2-70. (But note NORD-LOCK washers)
Dennis
RE: Torque for axle banjo and torque tube bolts - Nick Turley - 20-10-2017
If this is a help to you, I use 19 ft lbs
RE: Torque for axle banjo and torque tube bolts - Dennis Nicholas - 21-10-2017
Thanks Nick.
Is that with Stainless or HT steel bolts?
RE: Torque for axle banjo and torque tube bolts - Nick Turley - 21-10-2017
(21-10-2017, 11:21 AM)Dennis Nicholas Wrote: Thanks Nick.
Is that with Stainless or HT steel bolts?
HT Steel, not sure I would go for S/S here, it seems an unclear advantage.
RE: Torque for axle banjo and torque tube bolts - AustinWood - 21-10-2017
I'm not sure that torque settings mean much at all on old threads.
I always do things up firmly with a sensible size spanner - Not too big.
RE: Torque for axle banjo and torque tube bolts - Steve Hainsworth - 22-10-2017
I would advise not to use stainless bolts regardless, they have less tensile strength and elasticity than steel bolts and also tend to stretch or elongate/also prone to fracture.
Best to stick with H/T steel bolts on a stressed component like a axle center..
The comments about torque settings previous hold. use a short ring spanner judiciously.
Cheers Steve
RE: Torque for axle banjo and torque tube bolts - Zetomagneto - 22-10-2017
(22-10-2017, 11:13 AM)Steve Hainsworth Wrote: I would advise not to use stainless bolts regardless, they have less tensile strength and elasticity than steel bolts and also tend to stretch or elongate/also prone to fracture.
Best to stick with H/T steel bolts on a stressed component like a axle center..
The comments about torque settings previous hold. use a short ring spanner judiciously.
Cheers Steve
Absolutely right Steve, and they gall/ pickup before you reach full tightening potential.
No need of stainless on mechanical parts anyway.
I must confess to using them on bodywork and wing stays where high strength not needed,I use stainlees bolts with plain steel nuts to minimise galling.
RE: Torque for axle banjo and torque tube bolts - Dennis Nicholas - 23-10-2017
(22-10-2017, 11:13 AM)Steve Hainsworth Wrote: I would advise not to use stainless bolts regardless, they have less tensile strength and elasticity than steel bolts and also tend to stretch or elongate/also prone to fracture.
Best to stick with H/T steel bolts on a stressed component like a axle center..
The comments about torque settings previous hold. use a short ring spanner judiciously.
Cheers Steve
I believe the original bolts were high tensile grade R.
I have been looking around many websites hoping to find a comparison table to show the tensile strength, yield strength, and proof strength. BUT all tables seem to be in such a variety of differing units my poor old brain cell can't cope.(even different types of tons/tonnes/short and long tons/metric tons!!!)
However What I seem to have found is:
(1Mega Pascal MPa = 1N/mm squared = 145 psi
A2-70 =700 MPa = 700Newton Meters squared = 101,000 lbf/in squared. (psi)
R = 45 - 55 ton/in squared....using 50 and short ton (2000pounds)= 100,000 psi
S = 50 - 60 ton/in squared....using 55 ,, ,, ,, ,, = 110,000 psi
So it would appear that the A2-70 is not far off the tensile strength of the "R" bolts.
(also when you think that a Centurion tank used to weigh around 50 tons then that weight on a square inch is a fair old strain that the bolt can take.......so the proof load (load before permanent deform happens) would seem to be adequate??
Since there are 8 bolts round the banjo I am now visualising 8 Centurion tanks happily hanging off the banjo!!!!
I shall retire now for a pint of something strong to cool the brain cell.
Perhaps I have got it all wrong?? Has anyone seen a table that compares the various standards in comparable units?
Dennis.
RE: Torque for axle banjo and torque tube bolts - Colin Reed - 23-10-2017
HI Dennis,
The yield strength is what you need to look at as this is when you get permanent deformation ( ie stretch )
A2-70 is 304 s/s 65000ft lbs
Grade 5 90000ft lbs
As you will see about 2/3 of a grade 5 bolt
also the recommendations on previous posts as to not using s/s still apply
Hope that helps to Clarify things
RE: Torque for axle banjo and torque tube bolts - Dennis Nicholas - 25-10-2017
(21-10-2017, 06:09 PM)AustinWood Wrote: I'm not sure that torque settings mean much at all on old threads.
I always do things up firmly with a sensible size spanner - Not too big.
Thanks but with-ought any thoughts of criticism and belittling etc. I prefer factual figures to be quote so can relate to known specifications.
I had done up the bolts "firmly" with a six inch 5/16 ring spanner - what I thought was tight enough. Then I set my torque wrench to a low reading and gradually increased the setting till the bolt just moved to see what the torque actually was (within the known inacuracy 0f +/- 25% attributed to torque wrench settings) and it turned out to be significantly lower than 18lbft. The bolts were new with copper slip applied to prevent any corrosion.
Mr weight lifter of the year would apply a very different "firm" pressure to that which my elderly wife would apply
