G... Glossary of Fastener and Fixing Terminology

Galling stainless to galvanise and geomet coatings. sharp gimlet points extending to grain structure and includes grip length and details of grub screws information to avoid galling

GLOSSARY           ALPHA LOCATOR  

A  B  C  D  E  F  G  H  I  J  K  

L  M  N  O  P  Q  R  S  T  

   U  V  W  X  Y  Z     Number

G  back to the alpha locator

Galling is a severe form of adhesive wear which occurs during sliding contact of one surface relative to another. Clumps of one part stick to the mating part and break away from the surface. It can frequently occur when both the nut and bolt are made from stainless steel and also with high alloy steels, titanium or zinc coated fasteners. In the case of stainless steel using an A4 Nut on an A2 screw can sometimes resolve the problem. Lubrication of threads is the recommended action. Stainless steel  Galling

GALVANISE

Applying a coating of molten zinc to a fastener by dipping and then spinning off the excess; under cutting or re-tapping of nut threads is often required  Finish

The term is sometimes confusingly incorrectly applied to zinc electroplating and referred to as electro galvanising.

GEOMET ®

A high performance zinc flake surface coating that can be applied to fasteners. The coating consists of passivated zinc flakes that are bonded on to the metal surface. The coating can be coloured and eliminates the risk of hydrogen embrittlement associated with electroplated steels  Zinc flake

GIMLET POINT       

A gimlet point is a threaded point on a fastener, usually having a point angle of 45° to 50°. It is applied on woodscrews and Type AB self-tapping screws  Points

GRAIN STRUCTURE 

A crystalline structure in metals as observed under the microscope. Cold and Hot forging maintain the grain flow while Bright cut fasteners break the flow.

GRIP LENGTH    

Total distance between the underside of the nut to the bearing face of the bolt head; includes washer, gasket thickness etc.

GRUB SCREW

Term used for slotted non headed setscrews and incorrectly for socket set screws.

back to the alpha locator

galling stainless to galvanise and geomet coatings. sharp gimlet points extending to grain structure and includes grip length and details of grub screws