Plas-Tech® 30 installation guide and hole sizes


This article provides an installation guide for the high performance Plas-Tech® 30 Screws for Plastics



Installation animation


The illustrated moulded boss features a 1 Degree inclusive tapered hole. However, it is not a prerequisite. It is commonplace for these screws to be installed into drilled holes also.


To identify a suitable hole size for a selected screw diameter, choose a material from the boss geometry tables below closest to the application boss type and multiply the value in column A by the nominal external thread diameter.

For example: A 3.0 diameter high performance Plas-Tech® 30 Screw for Plastic being installed into ABS would require a 0.8 x 3.0 = 2.4mm guideline hole diameter (where 'd' = nominal external thread diameter).

Where possible, the inclusion of a counter bore is recommended. A counter bore helps reduce the risk of damage to the top of the boss, reduce stresses in the boss, helps with screw alignment and acts as relief for any material extruded to the head of the screw, allowing flush finishes.

To calculate the counter bore diameter, add 0.2mm onto the selected published screw head diameter.

Table 1   Table 2
Material - A - -  B - - C - Material - A - - B - - C -
ABS 0.80d 2.00d 2.00d PC GF30 0.85d 1.80d 2.00d
ABS/PC 0.80d 2.00d 1.80d LDPE 0.70d 2.00d 2.00d
ASA 0.78d 2.00d 1.80d HDPE 0.75d 1.80d 1.80d
PA4.6 0.73d 1.85d 1.70d PET 0.75d 1.85d 1.70d
PA4.6 GF30 0.78d 1.85d 1.90d PET GF30 0.80d 1.80d 1.70d
PA6 0.75d 1.85d 1.70d PMMA 0.85d 2.00d 2.00d
PA6 GF30 0.80d 2.00d 1.80d POM 0.75d 1.90d 2.80d
PA6.6 0.75d 1.85d 1.70d PP 0.75d 1.85d 1.70d
PA6.6 GF30 0.82d 2.00d 1.80d PP TF20 0.82d 2.00d 1.80d
PBT 0.75d 1.85d 1.70d PPO 0.75d 1.85d 1.70d
PBT GF30 0.80d 1.80d 1.70d PS 0.80d 1.80d 1.70d
PC 0.85d 2.50d 2.20d PVC 0.85d 2.50d 2.20d
  SAN 0.77d 2.00d 1.90d
The high performance Plas-Tech® 30 Screw for Plastic is a direct screw fastener for use in thermoplastics. Its design characteristics include a profiled thread root to assist plastic flow and stress reduction, a 30 degree flank angle to reduce boss bursting forces and an 8 degree pitch angle which combine to support low installation torques with high stripping torque values.
  • Reduced radial stress 
  • No material jam in the core area
  • Maximum resistance to relaxation
  • No material stress through plasticisation