Custom Size Drill Bits: When Standard Diameters Are Not Enough
Custom size drill bits solve non-catalogue diameters and tolerance targets without awkward workarounds. This guide covers diameter control, point styles, and quoting inputs.
Custom size drill bits are ordered when your print calls for a diameter that is not a standard catalogue step, or when you need a controlled tolerance band that standard drills cannot hold reliably in your material. The goal is not only to “hit a number once”, but to run production holes with predictable size and life.
What to Specify for Custom Diameter Drills
- Nominal diameter + tolerance (e.g. h7/H7 target hole strategy if applicable).
- Depth and required flute length; through vs blind holes.
- Material + hardness and whether you peck or continuous drill.
- Coolant method and pressure available for through-coolant tools.
- Any special point requirement (split point, flat-bottom, forming, etc.).
Diameter Control and Runout Reality
Even the best drill cannot overcome a high-runout holder. If you need tight hole size, specify your holder system and typical spindle runout so the tool and process are engineered together.
Related Products — Drills
Through-coolant drills for deeper holes where chip control drives size stability.
Production drills with predictable geometry for standard depth ranges.
Compare drill families and decide whether custom diameter is required.
See Our Custom Tooling Real Cases
Examples of large diameter and special drilling projects: https://solidcarbidedirect.com/custom-tooling-cases
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