COVID-19 - Auto parts are classified as critical infrastructure. We will continue to ship orders, but there may be a 2 to 3 day delay due to short staffing at the factory.

Screw & Bolt Head Styles

Head Styles Definitions - See Illustration Below 

  • Binding - undercut unless otherwise specified -not recommended for phillips recess
  • Fillister - deep slot used for counter bored holes
  • Flat Fillister - same as standard fillister without oval top
  • Flat 82 degree - used where flush surface is desired
  • Flat 100 degree - larger head than 82 degree used for thin metal soft plastic
  • Flat Trim - same as 82 degree except diameter and countersink depth reduced
  • Flat Undercut - standard 82 degree with lower 1/3 countersink removed for short screws
  • Hexagon - manufactured as trim hex or indented hex
  • Hex Washer - same as hexagon with washer section
  • Oval - same as flat head with rounded surface for appearance
  • Oval Undercut - similar to flat undercut with rounded surface
  • Oval Trim - same as oval - smaller diameter and countersink
  • Pan - recommended to replace round, truss binder
  • Round - general purpose (see pan head)
  • Round Countersunk - bolts only - similar to flat head with no driving recess
  • Round Washer - same as round head with integral washer for bearing surface.
  • Square Bolts - large bearing surface for wrench tightening
  • Square Countersunk - for use on  plow bolts
  • Square w/Set Screw - recommended for high torque assembly
  • Truss - similar to round head with larger diameter (see pan head)