PRU-100Heuristic screen

Countersink depth

Sheet metal · Machining

Scope and limits

Countersink depth versus local sheet thickness (knife edge / > 0.6 t) on recognised countersinks.

Standards and references

No standards reference is assigned to this check. The scope described above applies.

STEP examples for this check

Sheet metal · CC0-1.0

Countersink consumes the whole sheet

Model example

Look at the Ø8 mm countersink from above, then at the underside: the 90° cone is 2 mm deep in 2 mm sheet, so it ends in a sharp ring edge with no cylindrical land left.

Dimensions (approx.): 60 × 40 × 2 mm

Expected check result

PRU-100 should warn (not error) that the countersink leaves no land: the screw head would seat on a sharp edge and the hole can grow; a formed countersink, thicker sheet or a smaller screw are the alternatives. The countersink is also listed under detected features.

Finding expected

PRU-100

Compare: Countersink well inside the sheet

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Sheet metal · CC0-1.0

Countersink well inside the sheet

Model example

The 90° countersink is 1.8 mm deep in 4 mm plate (45 %), leaving a 2.2 mm cylindrical land.

Dimensions (approx.): 60 × 40 × 4 mm

Expected check result

PRU-100 must stay silent; this is the control for the knife-edge example.

No finding expected

PRU-100

Compare: Countersink consumes the whole sheet

Try in the viewer Download STEP