Counterbore Hole Size Chart for Shoulder Screws (ANSI Inch)
ANSI Inch counterbore hole size chart for shoulder screws, including pilot hole diameters for close, normal, and loose fits, counterbore diameters, and depths (inches)
Shoulder Screw Counterbore Hole Chart (ANSI Inch)
| Fastener Size (Thread) | Pilot Hole Diameter (in) | Counterbore Diameter (in) | Counterbore Depth (in) | ||
|---|---|---|---|---|---|
| Close Fit | Normal Fit | Loose Fit | |||
| #10 | 17/64 | 9/32 | 19/64 | 7/16 | 16/85 |
| 1/4 | 21/64 | 11/32 | 23/64 | 1/2 | 16/73 |
| 5/16 | 25/64 | 13/32 | 27/64 | 5/8 | 1/4 |
| 3/8 | 17/32 | 9/16 | 39/64 | 13/16 | 5/16 |
| 1/2 | 21/32 | 11/16 | 47/64 | 1 | 3/8 |
| 5/8 | 25/32 | 13/16 | 29/32 | 1 1/8 | 1/2 |
| 3/4 | 1 3/32 | 1 1/32 | 1 5/32 | 1 1/2 | 5/8 |
| 7/8 | 1 9/32 | 1 31/90 | 1 7/16 | 1 7/8 | 3/4 |
| 1-1/8 | 1 9/16 | 1 5/8 | 1 47/64 | 2 1/4 | 1 |
| 1-1/4 | 1 13/16 | 1 7/8 | 2 | 2 1/2 | 1 1/8 |
| 1-1/2 | 2 1/16 | 2 1/8 | 2 1/4 | 2 7/8 | 1 1/4 |
About ANSI Inch Counterbore Hole Sizes for Shoulder Screws
This ANSI Inch counterbore hole size chart for shoulder screws provides standardized dimensions according to American National Standards Institute (ANSI) specifications. It lists recommended pilot hole diameters for close fit, normal fit, and loose fit, along with the corresponding counterbore diameters and counterbore depths in inches.
Using accurate ANSI Inch counterbore dimensions ensures proper shoulder screw seating, head clearance, and reliable mechanical performance in inch-based fastening applications. This reference is essential for engineers, machinists, and designers working with ANSI Inch shoulder screws, including:
- Mechanical and product design projects requiring ANSI Inch shoulder screws for inch-based assemblies.
- Machining, drilling, and fabrication processes that need precise pilot hole and counterbore preparation for standard shoulder screws.
- Assembly and quality control operations ensuring proper fit, alignment, and flush seating of shoulder screw heads.
Key Terms in the ANSI Inch Shoulder Screw Counterbore Chart
- Pilot Hole Diameter: The drilled hole diameter defining shoulder clearance for the screw, categorized for close, normal, or loose fit.
- Counterbore Diameter: The circular recess machined to allow the shoulder screw head to sit flush or slightly below the surface.
- Counterbore Depth: The vertical depth of the recess matching the head height of the ANSI Inch shoulder screw.
- ANSI Standard: The American National Standards Institute specification defining dimensions, tolerances, and geometry for inch-series shoulder screws.
Referencing this ANSI Inch shoulder screw counterbore hole chart ensures consistent part design, precise manufacturing, and compliance with inch-based fastener standards. Proper use of these dimensions improves assembly quality, reduces errors, and enhances mechanical reliability.