Dry or Lube?

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Member
Location
Kent
If torqueing them up to a specific torque then DRY, theres a video somewhere showing a guy dry torqueing, and lubed torqueing. The lubed one strips the thread before hitting torque. If just using the good old FT torque method a bit of lube is fine if you have a good feel for it.
 
When a bolt is lubricated - less torque is required to achieve bolt axial load or tension. Reduction of torques for lubricated vs. dry bolts are indicated in the table below.

LubricantTorque Reduction
(%)
Graphite50 - 55
White Grease35 - 45
SAE 30 oil35 - 45
SAE 40 oil30 - 40
No lube0
https://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html

On the other hand, according to data collected and analyzed by Shigley and Mischke, there is not a correlation to an average difference in torque to tension of dry vs. lubricated fasteners. What the data indicated was that lubed fasteners acheive a desired preload at a much more consistent torque value. Applied torques on "Dry" fasteners on average yield roughly the same preload, but there is a much greater deviation from that mean or average value from dry fastener to dry fastener vs. lubed fastener to lubed fastener. If you are looking to control preload in fasteners to a tighter range, then lubricating them prior to torque will give more predictable results, not higher values compared to dry conditions - according to Shigley and Mischke. https://www.eng-tips.com/viewthread.cfm?qid=173061

Manufacturers, engineers and other industry experts seem to unanimously oppose using lubrication. On the other hand, some DIYers and self-appointed Internet forum experts claim to have used thread lube since the very dawn of time with nary a problem.
 

Andrew

Never Forgotten
Honorary Member
Location
Huntingdon, UK
So, all the wheels are on, little dab of copper on each nut.

How long a scaffold tube shall I use to torque them, and how many bounces for a 15 stone bloke?

Once spent an enjoyable afternoon on a motorway sliproad helping a tyre fitting mate balance on a scaffold pole to undo truck wheelnuts. Took him about 6 bounces to undo so maybe 3 to tighten? 🤣
 

Bury the Trash

Member
Mixed Farmer
So, all the wheels are on, little dab of copper on each nut.

How long a scaffold tube shall I use to torque them, and how many bounces for a 15 stone bloke?
the danger ,as already correctly mentioned in 2 or 3posts above is that grease/lubricant will make it easy to over tighten them , definitely doesnt help a torque wrench to click off where it should do.

spot of oil from on the stud thread from the oil can is a compromise to prevent corrosion but still take care when tightening.

because they will be checked shortly after or during first using for tightness see they aren't running back, wont they.
Copper grease is apparently not very healthy for you when it dries out and dusts or flakes and /or are potentially ingested is the theory as well.

edit "sounds like 15 stone bloke needs to stop with the pies ,:oops:does depend on how tall he is tho .lol."
 
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