M12 thread pitch (coarse vs fine)
M12 ISO coarse pitch is 1.75 mm; fine-series pitches are commonly near 1.5 mm when listed on drawings.
Mixing coarse and fine on the same nominal diameter yields different tap drills and gauge results.
Use the thread pitch chart tool on BoltLab, then the thread identifier if field threads look worn or double-started.
Pitch is axial distance per thread in millimeters for metric; always match tap, gauge, and nut class to the same series.
M12 pitch table
| Series | Pitch |
|---|---|
| ISO coarse (common) | 1.75 mm |
| Fine (typical when shown) | 1.5 mm |
| Tap drill (coarse) | 10.2 mm |
Design note
Fine threads allow finer adjustment and more threads in a blind hole; coarse threads strip less easily in softer materials when engagement length is short.
M12 links and tools
Open the bolt size chart (M12) for hex, pitch, and tap drill in one hub table.
Use tap drill size when pitch differs from coarse or you need a quick recalculation.
Run the thread identifier after you measure major diameter and pitch on a sample thread.
Compare stocked inch hardware with screw size conversion when you cross-shop bins.
Convert pitch units with the thread pitch chart tool when drawings mix mm and TPI.
Review metric vs unc thread naming before you mix UNC taps with metric holes.
Neighbor metric hub: bolt size chart (M11) for the next smaller shank.
Neighbor metric hub: bolt size chart (M13) for the next larger shank.