The 456M WSM says 7nm for the torque tube nuts? That's 5.2 ft lbs? Is that right? Seems way too loose to me. Image Unavailable, Please Login Image Unavailable, Please Login
That's wrong. 5.2ftlbs is close to what is used cam caps to head. You are talking torque tube bolts holding gearbox or motor right?
OK my logic in absence of markings on the bolt head 1-Carrol Smith m10 12.9 oiled 46ftlbs 2-if the 7 in the WSM was a 70 that would be 52ftlbs that's pretty close. 3-then most mechanics don't use a torque wrench from years of experience except on critical fasteners like rod bolts. So there is quite a range of torques there 4-then most guys us a clicker wrench that might have been calibrated once upon a time when new. 5-the stud is probably 8.8 class maybe 10.9 certainly not a 12.9. I doubt a 10.9 would be needed for that application. So on M10 approx torque industry accepted is 40/50/60ftlbs dry for M10 class 8.8/10.9/12.9 So I would work up to 50ftlbs and use my experience as to how the fastener feels as I torque ti to know when to stop before I destroy it.
Every torque spec on that page of the 456 manual is incorrect except for the first one (8mm fastener, 25nm). all the rest are too low. Maybe they got the units wrong and used Kg/m instead of NM. 70nm for a 10 x1.25mm nut it pretty high unless it is a 12.9 hardness. If you look at the specs for other 10 x 1.25mm fasteners are 50 to 59nm, which is what I would shoot for. I also do it by feel.
