# item.guide
Side-by-Side Comparison Metric Threads (ISO)

M1.6 Thread vs. M4 Thread

Comparing 2 standards across 8 specifications. 8 key differences identified.

Comparing:
M1.6 Thread
M4 Thread

M1.6 is a miniature ISO metric machine screw thread with a nominal major diameter of 1.6 mm and a standard coarse pitch of 0.35 mm. Requiring a 1.25 mm tap drill, it is the standard fastening thread for precision optical equipment, wristwatches, and micro-electronic assemblies.

View full M1.6 Thread spec sheet →

M4 is an ISO metric machine screw thread with a nominal major diameter of 4.0 mm and a standard coarse pitch of 0.70 mm. Requiring a 3.30 mm tap drill, it is the mandated standard fastener for VESA MIS-D (75×75 mm and 100×100 mm) computer monitor and small TV wall mounting brackets.

View full M4 Thread spec sheet →

Specification Comparison Table

8 Parameters
Parameter / Spec
Nominal Major Diameter
1.60 mm 4.00 mm
Standard Coarse Pitch
0.35 mm 0.70 mm
Fine Pitch (Optional)
0.20 mm 0.50 mm
Tap Drill Diameter
1.25 mm (75% thread engagement) 3.30 mm (75% thread engagement)
Minor Diameter (Internal)
1.221 mm 3.242 mm
Tensile Stress Area
1.27 mm² 8.78 mm²
Thread Profile Angle
60 degrees
Common Drive Size
PH2 / PZ2 / 3.0mm Allen / T20