hybrid 1043 Report post Posted January 12, 2015 Quite a good techincal video on fastening. Some of you wont be into this sort of thing, but its a good must for anyone building up a car. enjoy 1 Quote Share this post Link to post Share on other sites
turbolizard 38 Report post Posted January 12, 2015 This explanation has some of the individual factors explained quite well but ultimately the conclusions are quite wrong. Lubed bolts need less torque, not more. At about 13 minutes the presenter really goes off track. The reduction in friction in the lubricated bolts means there is more extension of the bolt (clamping force) with less applied torque, so the rule of thumb ratios he uses for torque that goes "into clamping" do not apply universally to dry and lubed threads as he assumes. His experiment actually shows this when he tightens all bolts to the same torque (20ft-lb). The lubed bolts rotate further - and are actually tighter (have more clamping force) than the unlubricated bolt at that point. If you look at torque tables from reputable fastener manufacturers you will be able to see their recommendations in practice. Lubricated threads require less torque to achieve the same stretch (clamping force) compared to dry fasteners. If you lubricate a thread and then torque it to its dry spec it will be over tightened. The presenter shows some data at 16:40 that actually demonstrates this - the bolts yield at lower torque when lubricated. Quote Share this post Link to post Share on other sites
BreakMyWindow 1874 Report post Posted January 21, 2015 I ended up watching all his engine building clips on youtube - He goes through the fundamentals pretty well. Pitty it's dinosaur technology though. Quote Share this post Link to post Share on other sites
