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Torque Settings (reformatted)


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#31 MRA

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Posted 05 December 2016 - 08:30 PM

Following up on ths old thread, I wanted a ready reconner for general purpose nuts & bolts based on the head/spanner size. Lifting the torque settings from the MPI workshop manual for metric 8.8 and UNF Grade 5 tensile strength and reworking...

	Nut/Bolt	Jaw	Spanner		Torque	
			mm			Nm	ft-lb
					
UNF	1/4 UNF		11.11	7/16 AF 	9	6
	5/16 UNF	12.7	1/2 AF 		25	18
	3/8 UNF		14.29	9/16 AF 	40	29
	7/16 UNF (bolt)	15.88	5/8 AF 		75	55
	7/16 UNF (nut) 	17.46	11/16 AF 	75	55
	1/2 UNF		19.05	3/4 AF 		90	66
	9/16 UNF (bolt)	20.64	13/16 AF 	135	99
					
Metric					
	M5		8	8mm 		
	M6		10	10mm 		10	7
	M8		13	13mm 		25	18
	M10		17	17mm 		45	33
	M12		19	19mm 		80	59

Hope this is useful

 

It could have been, however as you decided to compile your chart based on the head size it isn't that useful at all :(  it should be based on the thread and shank diameter, the fixing material, the thread manufacturing method, any heat treatment processes and the same for the threaded hole it fits into as these are all important and WILL have a detrimental effect on the torque wrench figure used.



#32 Deeppockets

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Posted 07 December 2016 - 06:21 AM

The shank diameter is the first column and for Grade 5 UNF and 8.8 Metric tensile which are approximately equivalent. The second column is the common hex head size in mm for the shank with the third column the spanner/socket usage.
 
The above figures are for dry fitment as torque loading also dependent on whether the threads are dry or lubricated. Here is useful site which has a bit on on thread lubrication types and effects: http://home.jtan.com...KIAT/kiat_2.htm .

 

So, for example, a general purpose 1/2" AF Grade 5 bolt will have a shank of 5/16" and a dry torque setting of 18 lb-ft.



#33 Abbot

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Posted 06 February 2017 - 09:02 PM

Now I am confused. I am rebuilding my engine and have just Torqued up the head to the values shown in my Haynes manual.  The values are for first stage 25 lbf ft and then the final stage of 50 lbf ft  .  The data sheet at the start of this thread shows 40 lbf ft as the final stage.

 

When I did apply 50 bf ft it was obvious to me that the resistance was not increasing and the wrench did not click.

So I think I have over stretched the bolts and not achieved the torque.  

 

Any ideas why the Haynes manual can be so wrong? or have I done something else that is stupid like oil on the threads.



#34 MRA

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Posted 12 February 2017 - 10:56 PM

Now I am confused. I am rebuilding my engine and have just Torqued up the head to the values shown in my Haynes manual.  The values are for first stage 25 lbf ft and then the final stage of 50 lbf ft  .  The data sheet at the start of this thread shows 40 lbf ft as the final stage.

 

When I did apply 50 bf ft it was obvious to me that the resistance was not increasing and the wrench did not click.

So I think I have over stretched the bolts and not achieved the torque.  

 

Any ideas why the Haynes manual can be so wrong? or have I done something else that is stupid like oil on the threads.

 

40 is the old figure 50 is the later figure for studs with crows feet on the end



#35 Abbot

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Posted 04 March 2017 - 11:47 AM

What is    'a crows foot on the end" ?



#36 MRA

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Posted 05 March 2017 - 09:06 PM

What is    'a crows foot on the end" ?

Its more a Y than a crows foot but these are the later stronger head studs



#37 Abbot

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Posted 06 March 2017 - 09:30 PM

ok thanks job done at 50 and no problems this time. Thanks



#38 rider4life

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Posted 16 August 2017 - 11:57 PM

thanks






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