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Single and Double Ended Plug Gauges

Options (mm)
Go +2.0µm No Go -2.0µm
Go +1.0µm No Go -1.0µm
Go +0.5µm No Go -0.5µm


Options (inches)
Go +0.00008" No Go -0.00008"
Go +0.00004" No Go -0.00004"
Go +0.00002" No Go -0.00002"


Ball Plug Gauges have many advantages over conventional Plug Gauges.

  • They are quick and easy to use because they can be inserted at any angle.
  • Due to the very small contact area of the ball, very good "feel" is imparted to the inspector and any roughness is easily detected.
  • They are very effective in detecting any bell mouthing or taper in the hole.
  • Tungsten Carbide Balls offer rugged resistance to impact, wear, temperature, humididty and corrosion.
  • Our standard tolerances are +2.0µm (0.00008") on the "Go" end and -2.0µm (0.00008") on the "No Go" end. However tighter tolerances are available at extra cost.
  • The Spheric-Trafalgar UKAS Laboratory can supply full Certification.
  • Handles can be engraved to your own requirements listing Part Numbers etc.
  • All stems are made from high quality stainless steel.


Construction Details

For ball sizes 5/32" (4mm) and above, the stem is inserted into a hole spark eroded into the ball and fixed using a specially developed Spheric-Trafalgar adhesive. Below 5/32" (4mm), the balls are brazed to the stems.