Reduced Torque with Lubricated Bolts
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.
| Lubricant | Torque Reduction (%) |
|---|---|
| Graphite | 50 - 55 |
| White Grease | 35 - 45 |
| SAE 30 oil | 35 - 45 |
| SAE 40 oil | 30 - 40 |
| No lube | 0 |
Example - Reduction of Torque when Bolt is Lubricated
The maximum tightening torque for a slightly lubricated 1" Grade 5 coarse bolt is 483 lbf ft. Dry bolt torque is approximately 30% higher - or 628 lbf ft.
Tdry = (483 lbf ft) (1 + (30%) / (100%))
= 628 lbf ft
If the bolt is lubricated with SAE 30 oil - the torque compared to a dry bolt is reduced with approximately 40%.
TSAE30 = (628 lbf ft) (1 - (40%) / (100%))
= 377 lbf ft
Note that if torque specified for a dry or slightly oiled bolt torque is applied to a lubricated bolt - the bolt may overload and break.
Related Topics
• Fasteners
Bolts, nuts and threaded rods - torque, tension and loads.
• Miscellaneous
Engineering related topics like Beaufort Wind Scale, CE-marking, drawing standards and more.
Related Documents
Bolt Stretching and Tensile Stress
Tensile stress and Hooke's Law.
Bolt Torque Calculator
Calculate required bolt torque.
Cast Iron Flanges - Stud Reference Chart
The number, diameter and length of studs for cast iron flanges class 125 and 250.
Grease - Temperature Limits
Temperature limits for grease - a combination of oil and thickener.
Improvised Torque Wrench
Improvise a torque wrench with a luggage scale.
Industrial Lubricants - Viscosities vs. ISO-VG Grade
ISO-VG viscosity grades for industrial lubricants.
ISO 2841 - Spark Plugs Metric Threads
Metric threads spark plugs according ISO 28741.
ISO 724 - Metric Threads
Dimensions of metric threads according ISO 724.
Metric Bolt Heads and Wrench Sizes
ANSI/SO, DIN and JIS bolts.
Metric Bolts - Minimum Ultimate Tensile and Proof Loads
Minimum ultimate tensile and proof loads for metric bolts with coarse or fine threads.
Metric Bolts - Tightening Torques
Recommended thightening torque metric bolts.
Metric Steel Bolts - Grades and Property Classes
Metric steel bolts, screws and studs - proof and tensile strength.
Oil Lubrication - Temperature Limits
Temperature limits for lubricating oils.
Steel Bolts - ASTM Grades
ASTM steel bolts - proof and tensile strength.
Steel Bolts - SAE Grades
SAE steel bolts - grades ranging grade 1 to 8.2 - proof and tensile strength.
Threaded Bolts - Stress Area
Threaded bolts tensile stress area.
Torque or Moment of Force - Online Converter
Torque or moment - the tendency of a force to rotate an object.
UNC and UNF - Unified Inch Screw Threads
ANSI/ASME B1.1 Unified National Thread - UNC Coarse series and UNF Fine series.
US Bolts - Head and Wrench Sizes
Hex Bolt, Lag Bolt, Square Bolt and Heavy Hex Bolt.
US Bolts - Tensile Strength and Proof Loads
Tensile strength and proof loads SAE bolts.
US Bolts - Tightening Torques
Recommended bolt torques.
US Hex Bolts - Inches
ANSI/ASME B18.2.1 Dimensions of Hex Bolts - Imperial units.
US Hex Bolts - Metric
ANSI/ASME B18.2.3M Dimensions of Hex Bolts - Metric units.
US Machine Screws - Dimensions
Machine screw diameters.
Whitworth Bolt Torques
Torque specifications Whitworth bolts.
Wrench Spanners - Inches vs. mm
Convert between US Inches and metric mm wrench and spanner sizes.