Screw locking instructions

Introduction
Drill size guide
Step 1
Step 2
Step 3
Step 4

Introduction

The locking provisions below are provided on all Wrekin Tristar, Highway, Unite, and Hercules manhole covers and gully gratings.

The cover and frame can typically be drilled and tapped in the locations shown below.

Preferably, screw locking can be provided as a factory fitted item. Please advise our sales team of your requirements at point of order.

Drill size guide

Set screw size	Drill size	Hex key size
M16 x Xmm**	14.5mm	14mm

Step 1

Drill through the cover and frame with an appropriate sized drill bit.

Step 2

Drill through cover with appropriate clearance drill bit.

Step 3

Tap frame with appropriate hand tap.

Step 4

Place the washer over the set screw, apply grease* to the set screw and lock using the appropriate hex key.

* For longevity, a grease or protection lubricant with anti-ageing & anti-wash-out characteristics should be considered for its advantageous protection performance.

** 5-20mm fastener protrusion