GEOFFREY   MILLER
       
 

Home

 
 

Sitemap

 
 

Range Rover

 
   

Advertisement

 
   

Engine

 
   

Cooling system

 
   

Electrical system

 
   

Ignition system

 
   

Instruments

 
   

Manual Gearbox

 
   

Automatic Gearbox

 
   

Transfer Box

 
   

Air Bags

 
   

Air Suspension

 
   

Steering

 
   

Hubs

 
   

Swivels

 
   

Helicoils

 
   

Headlining

 
   

Tailgate

 
 

Video

 
 

Psion Organiser II

 
 

Flymo LT1236 mower

 
  Links  
     
 

Range Rover pages

Helicoils

 
     
 

What do you do when, as has happened to me, the thread in an alloy component strips and you cannot then get the bolt to gain any purchase at the time of reassembly? You fit a helicoil.

     
 

A helicoil is made of a wire with a diamond-shaped cross-section, formed into a helical spring.

The kit contains instructions giving details of the diameter to which the original hole should be drilled so as to remove the remains of the old thread and allow insertion of a special tap, whose dimensions are correct for the size helicoil to be used. This cuts an over-size thread.

     
 

A helicoil of the correct size is mounted in the introducer and is then screwed into the conical nozzle, which compresses it sufficiently to fit into the pre-tapped hole. Because it is screwed in from the leading end, it goes in easily.

     
 

As the helicoil is inserted into the hole, it expands, so as to jam itself into the thread. It cannot be removed by reversing the insertion process, but can be screwed right through and out the other side.

The cross-piece is then broken off through the pre-formed weak spot.

The internal dimensions of the helicoil will then be correct for the chosen thread size.