Product and application brief
A flat countersunk self-drilling screw has a flat top and conical underside at the head, a tapping thread and a cutting drill point. The matching countersink is part of product selection: a drill point alone does not define the head seat or guarantee a flush finished connection.
Product forms and reference names
| Product form / field | Reference and distinguishing details |
|---|---|
| Cross-recessed flat countersunk | ISO 15482:1999 identifies cross-recessed countersunk-head drilling screws with tapping screw thread. ISO confirms the edition was reviewed in 2024. Specify the exact selected recess and requirements. |
| Phillips and Pozi catalogue forms | Bossard identifies BN 1879 as a Phillips form H flat countersunk drill screw and separately lists a Pozi form Z variant. Cross-recess names and drive sizes should be stated explicitly, not substituted on appearance. |
| Six-lobe flat countersunk | Bossard BN 33071 is a flat countersunk drill screw with hexalobular socket. Its approximate ISO catalogue reference does not establish cross-recess standard conformity for another drive. |
| Raised countersunk is a separate form | A raised or oval countersunk top is not the flat-top form shown here. ISO 15483 is a separate raised-countersunk drilling-screw reference; identify which head profile the drawing requires. |
Head-seat geometry
Identify the head diameter, height and included angle using the selected specification or drawing. Confirm the mating countersink geometry and material thickness. Do not assume that every metric, inch or drawing-defined countersunk screw uses the same angle.
Length measurement and thread designation
Provide length with units and the selected measurement convention. For a flat countersunk head, clarify whether the quoted dimension includes the head; do not transfer a pan-head under-head measurement without checking the drawing. Tapping-thread designation is distinct from a metric machine-thread designation.
Drilling point and material stack
Provide the point style or drawing and the sheet/support materials with individual thicknesses. Required drilling range belongs to the exact selected screw documentation; head shape or overall length does not establish a universal drilling capacity.
Reference names and production requirements
DIN 7504 P appears as a withdrawn legacy reference in Bossard catalogue listings with approximate ISO cross-references. Do not treat legacy and ISO names, proprietary codes or different drives as guaranteed equivalents. Specify material, construction, finish and inspection requirements independently of the generic illustration.
Specification fields
| Product form / field | Reference and distinguishing details |
|---|---|
| Identity | Flat countersunk head, exact drive, standard/edition or controlled drawing and revision. |
| Head and mating seat | Head diameter/height, included angle and the required countersink geometry from the selected specification. |
| Thread | Tapping-thread designation or specified inch system, diameter, profile/pitch and thread length where applicable. |
| Length | Nominal length and units with explicit measurement convention, plus drill-point and threaded lengths when specified. |
| Point and substrate | Drill-point type, documented required drilling range, sheet/support materials and individual thicknesses. |
| Material and finish | Required material/construction, coating and inspection documentation; no inferred hardness, corrosion life or assembly approval. |
| Quantity and attachments | Quantity in pieces, exact part designation and drawing or matching countersink/material-stack information. |
Common product questions
Is countersunk self-drilling the same as countersunk self-tapping?
Not necessarily. A drill-point screw has cutting-point geometry; a simple pointed tapping screw or countersunk machine screw is a different product identity even if the heads look alike.
Does every countersunk drill screw use the same head angle?
No universal angle is prescribed here. Select the required specification and verify the head and mating countersink geometry together; metric, inch and special drawing parts should not be assumed equivalent.
Is a raised countersunk head the same as a flat countersunk head?
No. Raised countersunk has a raised top profile. Specify the intended profile and reference; it is not automatically interchangeable with the flat-top form illustrated here.
Related self-drilling screw types
Product references
References checked 6 October 2026 explain product identity. Third-party model names and approvals are not FastenerBridge brand affiliation, stock or certification claims. Final geometry and requirements follow the selected specification.
Related specification guides
- Read standard numbers, editions and proposed alternatives
- Identify the thread system, pitch and mating fit
- Identify assembly inputs and product-specific installation instructions
- Explore related connection arrangements
These guides explain specification choices; they are not an approval, substitution rule or installation value for this product.