30 Piece Specimen Comparator
This has reference plates manufactured from electro-formed solid nickel, which give improved wear characteristics and definition of surface finish. It is invaluable for tactile and visual inspection of machined component finish. Metric Ra and imperial AA samples are included. Supplied in a PVC wallet (165 x 85 x 10 closed). Production is as standardised in ANSI B46.1 - 1978 military standard 45662.
Key Characteristics
Machining method
finish
Flat lapping
2, 4, 8μ, AA
Reaming
16, 32, 63μ, AA
Grinding
2, 4, 8, 16, 32, 63μ, AA
Horitzontal milling
16, 32, 63, 125, 250, 500μ, AA
Vertical milling
16, 32, 63, 125, 250, 500μ, AA
Turning
16, 32, 63, 125, 250, 500μ, AA
Parallels, Surface Finish & Hardness
Surface Finish
Any machined component has a surface geometry which consists of three basic elements:
Form or Curvature -
Whether the surface has irregular bumps or dimensional changes
Waviness -
Whether the surface has regular repetitive ripples or patterns (e.g. milling patterns)
Roughness -
The shapes or irregularities that are smaller than, and form part of the waviness pattern (e.g. material micro-structure)
Waviness and roughness are traditionally the most difficult elements to measure when comparing surface finish, however, they have a radical effect on the performance of the finished component. Variations will cause aesthetic appearance changes, component wear variations, oil retention variation etc. Many manufacturers therefore specify a range of roughness values which their components should be manufactured to, often expressed as: Ra, Rq (RMS), RzDIN, Ry, Sm,mm.
