DN-TAP-M14X1.25
The Plug Hole — M14×1.25 Tap
The spark plug thread. Restored, not forgiven.
- Spark plug thread — the most common of the four SAE sizes
- 14 mm diameter, 1.25 mm pitch
- Fine pitch — the coarse M14 is 2.0 mm, and that tap will not cut this hole
- High speed steel, M2 grade — 65 HRC hardened
- Holds its cutting edge to about 600 °C; plain carbon steel softens from 200 °C
- Titanium nitride coated — about 2,300 HV, three times the hardness of the steel beneath
- Coating 2–5 microns thick
- Tap drill 12.75 mm (75% thread)