Extension Spring Part Number System - In Metric Millimeter

StockSpringsCatalog.com Part Number System For Extension Springs in Metric Millimeter


Part Number


Extension Spring


Wire Diameter


Outer Diameter of Spring


Total Coils


Material Type


Length Inside Hook


Hook Type




Unit of Measure

Our Part Numbers Have Changed

Since we have created the new website, we have updated our dimensional part numbers to not have any decimal points. However, we have kept the three decimal spaces so remember to add the extra zeros where needed.

Previous Part Number


New Part Number


StockSpringsCatalog.com By Acxess Spring Part Number System In Metric Millimeter For Extension Springs

We have developed an easy stock spring part number system using the actual dimensions of the spring. This part number system for springs was developed to facilitate the creation and understanding of part numbers for springs. By using the actual dimensions of the spring in the spring part number we have made our part numbers for springs simple, but yet descriptive of the actual spring measurements in real time. Our part numbers consist of a series of numbers to describe each individual spring. Each part number is separated by hyphens to indicate different dimensional characteristics of a spring. Each series describes a different dimension. Below you will find a breakdown explanation of how StockSpringsCatalog.com part number system works for extension springs in metric millimeter.

  • The letter P stands for Part Number
  • The letter E stands for Extension Spring
  • The first series of numbers indicates Wire Diameter=WD
  • The second series, following the first hyphen, indicates Outer Diameter=OD
  • The third series, following the second hyphen, indicates Total Coils=TC
  • The fourth series, following the third hyphen, indicates Material Type
  • The fifth series, following the fourth hyphen, indicates Length Inside Hooks=LIH
  • The sixth series, following the fifth hyphen, indicates Hook Type
  • The seventh series, following the sixth hyphen, indicates Finish
  • The eighth series, following the last hyphen, indicates Unit of Measure Metric Millimeter=MM

Please look at the part number example below for a further explanation.

Extension Spring Part Number Example In Metric Millimeter:


  • P=Part Number
  • E=Extension Spring
  • 860=.860 Wire Diameter=WD
  • 12700=12.700 Outer Diameter=OD
  • 20.530=Total Coils=TC
  • MW=Material Type
  • 34.900=Lenght Inside Hook=LIH
  • CG=Hook Type
  • N=Finish
  • MM=Unit Of Measure Metric Millimeter


Material Type: BC=Beryllium Copper, HD=Hard Drawn, MW=Music Wire, OT=Oil Tempered, PB=Phosphor Bronze, SPR=Spring Steel, SST=Stainless Steel

Hook Type: CO=Closed Over Hook, MH=Machine Hook

Hook Type: *=Double Loop, **=Side Hook/Loop, ***=Extended Hooks

FinishBO=Black Oxide, GI=Gold Irridite, N=None, Z=Zinc

Unit of Measurement: MM=millimeters, IN=inches

StockSpringsCatalog.com By Acxess Spring Part Number System In Inches For Extension Springs.