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Technifast supply grooved pins with parallel or tapered grooves to DIN and ISO standards in mild steel or stainless steel A2. We can supply with either half length or full length taper grooves. Grooved pins are solid pins with three swaged grooves at 120° pitch along all or part of their length. They are commonly used to connect elements. When the pin is driven into a drilled hole of suitable diameter, the material displaced by the grooving process is forced back to partially close up the grooves and lock the pin into place.

One of the main advantages of using grooved pins are that they are easy to install and provide a permanent and reliable connection between parts. Technifast stock grooved pins in many different sizes and materials for different applications. When considering the correct pin you'll need to determine the length and diameter, plus the expansion diameter and the type of groove and groove length.

Grooved Pins

Advantages Of Grooved Pins

  • They do not need a precision reamed hole
  • They can have either parallel or tapered grooves
  • Parallel grooves give the pin higher resistance to vibration, but need more force to insert
  • They can be grooved on only part of the length, so that where the pin has to be firmly fixed in one part of an assembly, but have a clearance fit on the other, both parts can be drilled to the same diameter


Standard Description
DIN 1471 / GP1 Full Length Taper Grooves
DIN 1472 / GP2 Half Length Taper Grooves
DIN 1473 / GP3 Full Length Parallel Grooves
DIN 1474 / GP4 Half Length Reverse taper Grooves
DIN 1475 / GP5 Third Length Centre Grooves
BS 7047 Equivalent to DIN 1474
BS7049 Equivalent to DIN 1475 (But With Half Length Taper Grooves)
BS7050 Equivalent to DIN 1471
BS7053 Headed Grooved Pin
DIN 1469 Similar to DIN 1474 With Parallel Grooves & Circlip Slot
DIN 1470 Similar to DIN 1473 With Reduced Diameter At One End
DIN 1476 Headed Grooved Pin (Round Head)
DIN 1477 Headed Grooved Pin (Countersunk Head)
GP5 Equivalent to DIN 1475 But With Half Length Centre Grooves
ISO 8739 Similar to DIN 1473 But With Reduced Diameter At One End
ISO 8743 Similar to DIN 1475 But With Half Length Centre Grooves
ISO 8746 Headed Grooved Pin (Round Head)
ISO 8747 Headed Grooved Pin (Countersunk Head)

Grooved Pin Size Ranges

Nominal Diameter 1* 1.2* 1.5 2 2.5 3 4 5 6 8 10 12
Dimension C* 0.14 0.16 0.20 0.25 0.30 0.40 0.50 0.60 0.80 1.00 1.20 1.60
Diameter Over Grooves 1.05 1.25 1.60 2.15 2.65 3.20 4.25 5.25 6.30 8.30 10.35 12.35
Tolerance On Groove Dia. + 0.05, -0 +/- 0.05 +/- 0.1
Hole Size Max 1.025 1.225 1.525 2.025 2.525 3.025 4.075 5.075 6.075 8.090 10.09 12.11
Hole Size Min 1.000 1.200 1.500 2.000 2.500 3.000 4.000 5.000 6.000 8.000 10.00 12.00
Double Shear Strengths Tested To ISO 8749 kN 0.7 1.0 1.6 2.85 4.25 6.15 10.6 16.5 22.8 40.5 63.2 91.0
Lengths in mm
4mm Y Y Y Y                
5mm Y Y Y Y                
6mm Y Y Y Y Y Y Y          
8mm Y Y Y Y Y Y Y Y Y      
10mm     Y Y Y Y Y Y Y Y    
12mm     Y Y Y Y Y Y Y Y    
14mm     Y Y Y Y Y Y Y Y Y Y
16mm     Y Y Y Y Y Y Y Y Y Y
18mm     Y Y Y Y Y Y Y Y Y Y
20mm     Y Y Y Y Y Y Y Y Y Y
22mm       Y Y Y Y Y Y Y Y Y
24mm       Y Y Y Y Y Y Y Y Y
26mm       Y Y Y Y Y Y Y Y Y
28mm       Y Y Y Y Y Y Y Y Y
30mm       Y Y Y Y Y Y Y Y Y
32mm             Y Y Y Y Y Y
36mm             Y Y Y Y Y Y
40mm             Y Y Y Y Y Y
45mm             Y Y Y Y Y Y
50mm             Y Y Y Y Y Y
55mm                 Y Y Y Y
60mm                   Y Y Y
65mm                   Y Y Y
70mm                   Y Y Y
75mm                     Y Y
80mm                     Y  


*Only available in DIN 1473.

Length tolerances to js 15.

Why choose a grooved pin for your application?

The vast variety of pins can make it difficult to determine the right component for your requirements.  Dowel pins, spring pins and grooved pins can all be used in a similar manner, but which will work best for your project?  Read on to discover when a grooved pin might prove the most suitable option.

Grooved pins are typically manufactured from mild steel or stainless steel and usually have three grooves running at 120° pitch along all or part of their length.

The pins are solid, and the swaged grooves close together when driven into the hole which provides more elasticity than a regular dowel pin. This flexibility allows a grooved pin to securely lock into a simple drilled hole, or holes with a wider range of diameters, whereas a dowel pin is more suitable for high-precision reamed holes.

The grooves on the pin can either be parallel or tapered. Choosing a pin with parallel grooves will require a greater insertion force, but the benefits are that the pin gives a tighter fit and is unlikely to become loose if it’s subjected to vibration.

Grooved pins can work in a similar manner to spring pins and they have similar shear strengths when manufactured from steel but are stronger in stainless steel material.

By choosing the correct pin for your application, you can improve the quality and add longevity to the lifespan of your product.  For help in deciding the best components for your next project, contact the Technifast team for practical, friendly advice.

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