M42 Metric Thread Dimensions and Pitch

Below are the key dimensions for M42 metric threads: pitch, tap drill and clearance drill according to ISO 724:2023.

M42 Coarse (standard)

M42 Pitch:  4.5mm
M42 Tap Drill:  37.5mm
M42 Clearance Drill:  45mm
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M42 Metric Thread

M42 ISO metric thread profile illustration

Welcome to our M42 Metric Thread Page, your comprehensive reference for swift assessments on M42 metric threads. We've compiled an exhaustive database for all common metric threads you'll implement in your parts, outlining crucial measurements such as thread pitch, tap drill, and clearance drill. This page is an all-in-one solution for engineers, machinists, and hobbyists seeking dependable, precise data.

M42 Coarse Pitch Dimensions

Nominal Size
d=D
p
r
d2=D2
d3
D1
h3
H1
Tap Drill
M42
42
4.5
0.65
39.077
36.479
37.129
2.76
2.436
37.5
All dimensions stated in are mm (millimetre)

M42 Fine Pitch Dimensions

| Nominal Size | d=D | p | r | d2=D2 | d3 | D1 | h3 | H1 | Tap Drill | |--------------|-----|-----|-------|--------|--------|--------|-------|-------|-----------| | M42x1.5 | 42 | 1.5 | 0.217 | 41.026 | 40.16 | 40.376 | 0.92 | 0.812 | 40.5 | | M42x2.0 | 42 | 2 | 0.289 | 40.701 | 39.546 | 39.835 | 1.227 | 1.083 | 40 | | M42x3.0 | 42 | 3 | 0.433 | 40.051 | 38.319 | 38.752 | 1.84 | 1.624 | 39 | | M42x4.0 | 42 | 4 | 0.577 | 39.402 | 37.093 | 37.67 | 2.454 | 2.165 | 38 |

All dimensions stated in are mm (millimetre)

ISO Metric Thread profile

d=D: Major Diameter
p: Pitch
r: Root Radius
d2=D2: Pitch Diameter
d3: Minor Diameter Male Thread
D1: Minor Diameter Female Thread
h3: Thread Height Male
H1: Thread Height Female

Major Diameter

The Major Diameter is the largest diameter on the thread and is measured from the thread crest to crest (peak of the thread).

Pitch

This is the distance (mm) from one thread to the next, this can be measured from tip to tip or groove to groove. Pitch can also be defined as TPI, which stands for threads per inch.

Minor Diameter

Minor Diameter is the smallest diameter on the thread and is measured from the thread root to root (Bottom of the thread).

Thread Angle

The angle between the thread faces. 60 degrees in the example above.

Right-Hand Thread

The thread will assemble when rotated clockwise. "righty tighty lefty loosely"

Left-Hand Thread

The thread will assemble when rotated counter-clockwise.

Frequently Asked Questions

What is the pitch of an M42 thread?

The pitch for an M42 thread is 4.5 mm.

What is the tap drill for an M42 thread?

The tap drill for an M42 thread is 37.5 mm.

What size is a clearance hole for an M42 thread?

The clearance drill for an M42 thread is 45 mm.

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