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Calculated O-Ring Cord Length

O-Ring Cord

How to calculated O-Ring cord length needed:

( ( OD + ID ) / 2 ) x Pi = length Pi=3.14159

Inside Diameter (ID) = Outside Diameter (OD) - twice the cross section (C/S)
ID = OD - (2 x C/S)

Vulcanized/Spliced O-ring Formulas
(determining the size or cut length of a vulcanized/spliced o-ring)

Determine the inside diameter if you know the cut length and the cross section:
(cut length ÷ 3.142) – 1(cross section)=inside diameter
e.g. –   124.375” cut length and a .313” cross section
(124.375 ÷ 3.142) -1(.313) = 39.272”inside diameter

Determine the outside diameter if you know the cut length and the cross section:
(cut length ÷ 3.142) + 1(cross section)=outside diameter
e.g. –   124.375” cut length and a .313” cross section
(124.375 ÷ 3.142) +1(.313) = 39.898”outside diameter

Determine the cut length if you know the inside diameter and the cross section:
(inside diameter + 1X the cross section)3.142=cut length
e.g. -    19.750” inside diameter X .500” cross section
(19.750 + .500)3.142=63.625” cut length

Determine the cut length if you know the outside diameter and the cross section:
(outside diameter - 1X the cross section)3.142=cut length
e.g. -    19.750” inside diameter X .500” cross section
(20.750 - .500)3.142=63.625” cut length

Make your own O-rings with O-ring Cord and O-ring Glue. How To Make an O-ring:

To calculate the correct length of cord required, (( OD + ID ) / 2 ) x Pi = Length. This will then give the correct length of cord required. Using the splicing aid and a very sharp knife. make a cut in the material at a right angle. All surfaces to be glued must be free of oil or grease. Avoid touching the surfaces. A thin layer of Cyanoacrylate Adhesive O-ring Glue should be spread over one side of the cut. A thin layer provides the best results. In order to join the two sides cleanly, use the V section on the splicing aid. Match both surfaces together and press firmly for 15 seconds. The glue must dry for 60 seconds before mounting the O-ring.

Information within is believed to be accurate and reliable. However, The O-Ring Store, LLC makes no warranty, expressed or implied, that parts supplied in this material will perform satisfactorily in specific applications. It’s the customer’s responsibility to evaluate the material prior to use.