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Pozi Countersunk Head Thread Forming Screw for Plastic

SKU: TFS06 Category:

FasPlas Pozi Countersunk thread forming screws are specifically designed for plastic and allow the screw to tap its own threads into this material, whilst the countersunk head allows the screw to rest flush against the surface leaving a smooth finish.

  • Pozi Drive
  • Choice of 30°, 45° and 60° thread angle
  • Range of diameters and thread lengths
  • Manufactured in steel zinc or zinc & black, with stainless steel also available.

Pozi countersunk thread forming screws are ideal for installation into a pre-drilled or moulded hole in softer materials such as plastic. These screws are available with 30°, 45° and 60° degrees thread angles, with the latter two featuring a trilobular body, giving a wider choice to suit a variety of applications. Using an angled thread allows for a better and cleaner mating with the contact material when forming the thread engagement, and a better resistance to ensue a more secure fit. This in turn leads to a high pull performance ensuring that the screws stays in position.

FasPlas Pozi Countersunk thread forming screws are available in a wide range of diameters and lengths. As well as being available in various sizes they are also manufactured in different materials and finishes – zinc steel, black steel and stainless steel, with others available on request.

All stocked sizes are listed below. FasPlas Pozi Countersunk thread forming screws are available to order in non-standard sizes and finishes, including small volume manufacture, modifications and custom parts to drawings.

30° Flank Angle 45° Flank Angle
Diameter /
Length (mm)
2.2 2.5 3 3.5 4 5 6 1.8 2.2 2.5 3 3.5 4 5 6
4 prod-tri-spacer prod-tri-spacer
5  prod-tri-spacer prod-tri-spacer prod-tri-spacer
6
8
10
12
14
16
18
20
25
30
= Steel (Zinc or Black Zinc)
= Stainless Steel
60° Flank Angle
Diameter /
Length (inch)
2.28 4.20 6.19 8.16 10.14
3/16″
1/4″
5/16″
3/8″
7/16″
1/2″
9/16″
5/8″
3/4″
= Steel (Zinc or Black Zinc)

Thread Forming Screws – Design Considerations

When specifying thread forming screws for plastics, these factors should be considered:

  • Hole size and design
  • Type, grade and thickness of plastic
  • Installation depth
  • Required application and strip out performance

Why use a Pozi Countersunk Thread Forming Screw for Plastic?

  • Good engagement between the driver and screw is required
  • To achieve a smooth, low profile flush finish in the application

Standard dimensions are as below, although additional sizes and custom made thread forming screws are available.

pozi countersunk threadforming screw technical drawing

30° Flank Angle 45° Flank Angle
D Diameter 2.2 2.5 3 3.5 4 5 6 1.8 2.2 2.5 3 3.5 4 5 6
C – max 1.85 2.25 2.55 3.05 3.55 4.06 5.06 6.06
D1 – max 3.80 4.70 5.50 7.30 8.40 9.30 11.30 4.40 5.50 6.30 7.35 8.40 10.00
K 1.30 1.75 2.05 2.80 3.25 3.40 3.80 1.30 1.50 1.65 1.90 2.20 2.50
Recess 1 1 1 2 2 2 2 0 1 1 1 1 2 2 2

pozi countersunk thread forming screw 60 degree technical drawing

60° Flank Angle
D (Gauge) 2.28 4.20 6.19 8.16 10.14
D (Inch) – max 0.089 0.123 0.143 0.179 0.208
C (Inch) – max 0.092 0.127 0.147 0.185 0.212
D1 (Inch) – max 0.72 0.225 0.279 0.332 0.385
K (Inch) – max 0.051 0.067 0.083 0.100 0.116
Recess 1 1 2 2 2

*For guidance purposes only