Coiled Spring Pins

Coiled Spring Pins

ISO 8748, BS 7057, DIN 7344, ISO 8750, BS 7058, DIN 7343

Coiled spring pinss consist of 2-1/4 coils of spring steel or stainless steel and have swaged chamfers at each end. They are designed for plain drilled holes, but countersinking makes insertion easier.
Torqbolt Coiled Spring Pins are available in either standard duty (ISO 8750) or heavy duty (ISO 8748) to provide options for strengths, flexibility and diameter.
Heavy Duty: ISO 8748 / BS 7057 / DIN 7344, typically used in high shear strength applications and hardened host materials.
Standard Duty: ISO 8750 / BS 7058 / DIN 7343, offer the best balance between flexibility and strength and are recommended for most applications.

Coiled Spring Pin Standards

ISO 8748 BS 7057 DIN 7344 ISO 8750 BS 7058 DIN 7343

Advantages of Coiled Spring Pin

  • The Coiled design improves shock absorption as the load is spread over more than one coil.
  • Assembly is easier as the insertion force needed is lower.
  • The pins cannot interlock when in bulk, which is a benefit when they are to be barrel plated or installed using bowl-fed equipment.

Coiled Spring Pin Finishes

Coiled Spring Pins are normally supplied with a plain oiled finish. Steel pins may be given a protective finish such as zinc, phosphate, etc but for electrolytically applied finishes it is essential to de-embrittle the pins immediately after plating. Since the de-embrittlement process is not completely reliable, non-electrolytic finishes or stainless should be used for safety-critical applications. Where pins are to be used in plastic assemblies, it is recommended that they be de-oiled before use to avoid embrittlement of the plastic.

Coiled Spring Pin Finishes

Nominal Diameter, mm 0.8 1 1.2 1.5 2 2.5 3 3.5 4 5 6 8 10 12 14 16
Expanded Diameter                                
ISO 8750 Min 0.85 1.05 1.25 1.62 2.13 2.65 3.15 3.67 4.2 5.25 6.25 8.3 10.35 12.4 14.45 16.45
Max 0.91 1.15 1.35 1.73 2.25 2.78 3.3 3.84 4.4 5.5 6.5 8.63 10.8 12.85 14.95 17
ISO 8748 Min       1.61 2.11 2.62 3.12 3.64 4.15 5.15 6.18 8.25        
Max       1.71 2.21 2.73 3.25 3.79 4.3 5.35 6.4 8.55        
Recommended Min Min 0.8 1 1.2 1.5 1.99 2.49 2.99 3.48 3.98 4.95 5.95 7.93 9.93 11.9 13.85 15.85
Hole Size Max 0.84 1.04 1.24 1.6 2.1 2.6 3.1 3.62 4.12 5.12 6.13 8.17 10.2 12.22 14.25 16.25
Minimum Double Shear
Strengths-Tested to ISO 8749, kN
                               
Spring Steel (ISO 8750)       1.45 2.5 3.9 5.5 7.5 9.6 15 22 39 62 89 120 160
Spring Steel (ISO 8748)       1.9 3.5 5.5 7.6 10 13.5 20 30 53 30      
Stainless Steel (ISO 8750)       1.05 1.9 2.9 4.2   7.6 11.5 16.8 30 30      

Coiled Spring Pin Materials

  • Spring Steel
  • Austenitic Stainless Steel

Material Grades

  • Carbon Steel 1018, 1020, 1040, 1045
  • Alloy Steel 4130, 4140, 4142, 4340, 6150, 8620
  • Chrome Moly Steel 25CRMO4, 21CRMOV5-7, 42CRMO4, 42CRMOV4-6
  • Austenitic Stainless Steel 301, 302, 303, 304, 316, 317, 321, 310, 309, 329, 347 & 348
  • Martensitic / Ferritic Stainless Steel 403, 405, 409, 410, 414, 416, 418, 420 & 430F
  • Super Austenitic Stainless Steel 904l, 254-Smo, 253Ma, Alloy 20, Sanicro Alloy 28, Al-6xn, 310Moln, Alloy 230, Alloy 330 , Alloy 333
  • Precipitation Hardening Stainless Steel Alloy A-286, A453 GRADE 660, 17-4 PH, 15-5 Ph , 15-7 Ph, 17-7 Ph
  • Nitronic 50 , 60 ( xm-19), 30, 32, 33, 40
  • Duplex 32205 (F60), 31803 (F51);Super Duplex 32750 ( F53) , 32760 (Zeron 100), (F55), 329, Ferralium 255, 255FG46
  • Inconel 600, 601, 602, 603, 617, 625, 686, 702, 713, 718, 725, 738, 740, 783, X-750, 701, 901, 939
  • Incoloy 800, 800H, 800HT, 825, 925, 926, 945
  • Hastelloy C276, C22,C-2000,C4,B, B2, B3, G30, X, N
  • Monel Alloy 400, K-500, R405
  • Nimonic Alloy 80A, 90, 105, 115, 263
  • Titanium Grade1, 2, 3, 4, 5, 6, 7,8, 9, 11, 12, 19,23
  • Nickel 200, 201
  • Copper Nickel 70/30, 90/10
  • Silicon Bronze C651, C655, C656
  • Cobalt Alloys Invar 36 / 42, Waspalloy, MP35N / 159, Stellite 3/6/12/21, Rene 41, L605
  • Molybdenum Grade 361/363/364/365
  • Durehete 900/950/1055, JETHETE X19/M152, Hiduron 130/190, Tantalum, Zircoloy, Aluminium Alloy 2024, 6061, 7075