The field name for the matte, satin or frosted look of micropitted tooth flanks, often in a band near the root or tip. Light frosting may stabilize after running in, but frosting that spreads or deepens removes profile and leads to macropitting. Inspectors photograph it with consistent lighting so the area can be compared between inspections.
Frosting on the high-speed pinion has spread halfway up the flank since the last borescope, that's not stabilizing.
Also heard as
- frosted
- gray staining
Related terms
Micropitting
Very fine surface fatigue pits, too small to see one by one, that give tooth flanks a dull gray look.
Fingernail test
Shop check of dragging a fingernail across a tooth flank to judge whether surface damage has real depth.
Lambda ratio
Oil film thickness divided by combined surface roughness, showing how well the lubricant separates the teeth.