cadSet/text-to-cad/skills/cad/references/cad-skillx/atomic/counterbored-hole-creation.atomic.md

Counterbored Hole Creation Atomic Skill

When to use

• A fastener hole needs a cylindrical recess so a socket head, cap screw head, or flat seating surface sits flush or below the top face.
• The request mentions counterbore, counterbored hole, socket head screw, cap screw, recessed screw head, or flat-bottom screw seat.

Do not use when

• The screw head requires a conical countersink rather than a cylindrical counterbore.
• The feature is a bearing pocket, large cylindrical recess, decorative ring, or simple through hole.
• The part has no fastener-seat function.

Recognition features

• Through hole plus larger coaxial shallow cylindrical recess.
• HoleWzd evidence for counterbored screw holes.
• Descriptions mention recessed screw heads, socket head screws, counterbore depth, or flush mounting.
• Often appears on mounting plates, brackets, flanges, and covers.

Core invariants

• Counterbore axis and through-hole axis are identical.
• Counterbore diameter must be larger than through-hole diameter.
• Counterbore depth must be enough for the screw head but not cut through the part unless requested.
• Create the hole as one standard feature when possible to preserve fastener intent.
• Pattern the complete counterbored hole feature when repeated.

Parameter roles

• through_hole_diameter defines screw clearance.
• counterbore_diameter defines head clearance.
• counterbore_depth defines head seating depth.
• fastener_size defines standard screw selection.
• placement_point defines hole center.
• end_condition defines through, blind, or up-to-next behavior.

Construction sequence

1. Select the mounting face where the screw head sits.
2. Place the hole center from datums or pattern references.
3. Create a counterbored hole feature with through diameter, counterbore diameter, and counterbore depth.
4. Confirm the counterbore opens on the correct face.
5. Pattern or mirror the full counterbored hole feature if repeated.
6. Add small entrance chamfers only after the counterbore is correct.

Common failures

• Modeling only a shallow large circle without the through hole.
• Reversing the counterbore to the wrong side of the part.
• Making counterbore and through-hole diameters equal.
• Using countersink geometry for a socket head screw.
• Patterning only the through hole and forgetting the recess.

Evidence summary

• Latest run evidence: 49 accepted atomic insights matched counterbored hole creation.
• Strong repeated names include create_counterbored_hole, use_hole_wizard_for_counterbored_holes, and create_counterbore_hole_for_socket_head_screw.
• Frequent operations in the latest run: HoleWzd, Cut, LinearPattern, MirrorPattern, Chamfer.
• Source model examples: 020555, 028735, 031527, 079425, 080632, 086114, 096301, 144289, 146696, 174675, 202122, 211326, 217613, 225627, 227232.
• Source: CAD-SkillX offline review of SCAD58 descriptions, STEP summaries, and SolidWorks feature evidence.

Retrieval metadata

Triggers:

• counterbored hole
• counterbore
• socket head screw
• cap screw
• recessed screw head

Secondary triggers:

• flush screw
• counterbore depth
• counterbore diameter
• mounting hole
• fastener seat

Operation triggers:

• hole wizard counterbore
• cut counterbore
• pattern counterbored hole
• chamfer hole edge

Exclusions:

• countersink
• bearing pocket
• decorative ring
• plain through hole