Shop Math Worksheet Generator — Tap Drill, Counterbore, Hardness & Material Data

How It Works

1. Fill In Tap Drill Section

   Select thread type, size, and engagement %. Skip if no tapped holes in the job.

2. Fill In Counterbore Section

   Select screw type, size, and fit class. Skip if no counterbored holes.

3. Use Hardness Conversion

   Enter a value on any scale (HRC, HRB, HB, HV) and convert to all others.

4. Identify Material Grade

   Browse 20 common grades with machinability, hardness, and properties.

5. Print Combined Worksheet

   Summary section shows all filled-in values in compact printable format.

Built For

• Machinists preparing reference worksheets for each new job
• Shop foremen standardizing job packet documentation
• Apprentices learning machine shop reference calculations
• Quality inspectors converting hardness values for material verification
• Tool crib operators looking up requirements for job kitting
• Maintenance mechanics creating reference sheets for repairs

Features & Capabilities

Four Combined Sections

Tap Drill, Counterbore/Clearance, Hardness Conversion, and Material ID — the four calculations used most during setup.

Collapsible Sections

Each section collapses with completion indicators showing which have data.

ASTM E140 Hardness

Polynomial curve fits per ASTM E140 for accurate conversion across full range of each scale.

20 Material Grades

1018, 1045, 4140, 4340, 303, 304, 316, 17-4PH, A2, D2, and more with machinability and hardness.

Combined Summary

Bottom section collects all results for single-page printing.

PDF Export

Export complete worksheet as branded PDF for job packets.

Assumptions

• Tap drill calculations use ASME B1.1 minor diameter formula: Minor Dia = Major Dia - (1.0825 x Pitch)
• Counterbore dimensions per ASME B18.3 (SHCS) and ASME B18.2.1 (hex cap screws)
• Hardness conversions use ASTM E140 polynomial curve fits for Rockwell C, Rockwell B, Brinell (HB), and Vickers (HV)
• Material properties database covers 20 common steel grades with published nominal composition and machinability data
• Each worksheet section operates independently; unfilled sections are omitted from the combined summary
• Hardness conversion valid within the standard ranges defined by ASTM E140 (HRC 20-68, HRB 0-100, HB 100-739)

Limitations

• Hardness conversions are approximate; ASTM E140 explicitly states that conversions are not mathematically exact and vary by material
• Tap drill section is simplified; advanced tap drill calculator provides more sizes, engagement options, and drill cross-referencing
• Material database covers 20 common grades only; specialized alloys require the full steel grade decoder
• Hardness conversion outside published ASTM E140 ranges (below HRC 20 or above HRC 68) uses extrapolation with reduced accuracy
• Combined summary is designed for shop floor reference; not intended as formal quality documentation
• Does not include surface finish, tolerance, or dimensional measurement calculations

References

• ASTM E140 - Standard Hardness Conversion Tables for Metals (Rockwell, Brinell, Vickers, Knoop)
• ASME B1.1 - Unified Inch Screw Threads (tap drill sizing formulas)
• ISO 261 - ISO General Purpose Metric Screw Threads (metric tap drill basis)
• ASME B18.3 - Socket Head Cap Screws (counterbore dimensions)
• ASME B18.2.1 - Square and Hex Bolts and Screws (hex cap screw head dimensions)
• Machinery's Handbook, 31st Edition - Hardness Testing, Thread Data, and Fastener Dimensions

Frequently Asked Questions