Tapping
Tapping creates internal threads in a hole to allow attachment of threaded fasteners.
While the principle is simple, achieving a reliable joint in sheet metal or technical plastics requires
following several criteria: choice of thread type, engagement depth, minimum
distances between holes, and matching material thickness to thread depth.
Holes are machined at the same time as the profile, either by laser or CNC router, and threads are
made in a subsequent step.
Our application automatically filters available thread sizes according to material,
thickness and required clearances relative to other elements.
Thread Engagement
Thread engagement represents the percentage of screw threads that properly mesh with
the tapped hole threads. To ensure required mechanical strength, tension and
shear factors must be considered according to application. Adequate engagement ensures forces are
distributed evenly across multiple threads, avoiding stress concentration.
Thread Pitch and Standards
Thread pitch indicates the number of threads in a given space. We support three systems:
- SAE: Format ½-20 (½" diameter, 20 threads/inch)
- Metric: Format M10-1.5 (10 mm diameter, 1.5 mm between threads)
- ANSI: Format 10-32 (standardized size 10, 32 threads/inch)
Coarse vs Fine Thread
Coarse threads have a wider pitch (fewer threads per inch), while fine threads
have a reduced pitch (more threads). Coarse threads are more common and more resistant to
stripping. Fine threads offer a more precise fit but require greater engagement
depth and are more sensitive to galling during high-speed tightening.
Minimum thickness and alternatives
Tapping directly into sheet metal requires enough material to form at least 2 complete threads —
the threshold our application guarantees. Below that thickness, there aren't enough engaged threads left to
hold the load and the screw eventually strips out. The thread pitch therefore sets the minimum thickness: a coarse
pitch needs more material than a fine pitch to reach the same number of threads.
When the sheet is too thin for direct tapping, prefer:
- a self-clinching (PEM) nut or another press-installed insert — see the hardware section;
- a welded nut on the back of the part when the thread has to carry higher loads.
Where tapping isn't offered: on 304 and 316 stainless steel, direct tapping is replaced by
PEM inserts
(the tap tends to gall and break in stainless). On galvanized steel, tapping options are limited.
The application automatically filters the material/thickness combinations that are actually available.
Tapped parts may have a slight cutting oil film around holes. All threads are right-hand, made through the full
thickness and perpendicular to the surface.