The main comparison is the complete geometry
An undercut PCB drill has a reduced body behind the cutting section. When comparing it with a standard drill, look at the cutting section, body geometry and working length together. The name alone does not establish which tool will perform better in a particular process.
Compare the catalogue families
| Specification | Standard drills | Undercut drills |
|---|---|---|
| Catalogue cutting diameter | 0.075–3.175 mm | 0.25–1.20 mm |
| Listed shank | 3.175 mm | 3.175 mm |
| Listed overall length | 38.1 ± 0.1 mm | 38.1 ± 0.1 mm |
| Geometry to check | Full drill drawing and flute dimensions. | Cutting section plus reduced body dimensions. |
These figures describe the standard and undercut families in our catalogue. They are not industry-wide limits or a live stock list.
Use the board and process to frame the choice
Record the board material, stack thickness, required holes and machine setup. If replacing an existing tool, compare the actual drawing. Identical nominal diameters do not mean the cutting and body geometries are interchangeable.
A useful trial keeps the comparison controlled
- Agree the hole-quality and inspection requirements.
- Record tool dimensions, material and machine settings.
- Use comparable board stacks and inspection conditions.
- Document tool condition and any changed process variables.
- Review the findings before extending the trial into production.
Questions buyers often need to resolve
Is an undercut drill always better?
No universal ranking follows from the family name. Evaluate the full tool and application against defined acceptance criteria.
Can a standard and undercut drill share a shank size?
Yes. Both catalogue families shown here list a 3.175 mm shank, while their cutting diameter ranges and geometry differ.
Does a geometry change guarantee less breakage?
No. Breakage also requires inspection of the tool, holder, spindle, workpiece support and operating conditions. Use the PCB drill breakage checklist to gather evidence.
Read the dimensions guide or send your application brief before selecting a trial tool.
Discuss your application
Share the board material, tool dimensions and the issue you are seeing.
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