Point Larger than Shank Ball-Lock Punches
Punches with a working tip diameter larger than the retainer shank — pierce larger holes through standard-bore retainers without tooling modifications. Available in ejector and regular types, Heavy Duty only, with 14 coating options in inch and metric.
Coating Selection for Point Larger Punches
Point larger punches experience higher lateral forces due to the overhang between tip and shank. Coatings with low friction coefficients reduce bending stress at the transition zone:
| Coating | Hardness (HV) | Key Benefit for Point Larger |
|---|---|---|
| CRN | 1,750 | Good general protection, cost-effective baseline |
| TiCN (XCD) | 3,000 | Low friction reduces lateral load on overhanging tip |
| TiAlN (XNA) | 3,300 | Best heat resistance for high-speed stamping |
Why the Point Is Larger than the Shank
Standard ball-lock punches have a working tip equal to the shank diameter. This limits the hole size to the maximum retainer bore available. Point larger punches solve this constraint:
- Problem: You need a 20mm hole but your retainer system only accommodates 16mm shank punches.
- Solution: A point-larger punch with a 20mm tip on a 16mm shank. The retainer holds the 16mm shank; the 20mm tip pierces the larger hole.
- Structural design: The transition from larger tip to smaller shank is precision-ground with a radius to minimize stress concentration. M2 HSS at HRC 62-64 provides adequate strength for the reduced cross-section.
- Maximum ratio: Typical maximum point-to-shank ratio is 1.5:1 for Heavy Duty applications. Beyond this ratio, consider a larger retainer system instead.
When to Use Point Larger Punches
Mixed Hole Size Progressive Dies
Progressive dies with both small and large holes where standardizing on one retainer bore size simplifies tooling inventory.
Why point larger fit: Run all punches through the same retainer system — small holes use standard punches, large holes use point larger. One retainer size, one punch puller, one maintenance procedure.
Retrofit Without Reboring
Existing die sets where enlarging retainer bores would compromise punch plate strength or require expensive reboring.
Why point larger fit: Drop-in replacement using existing retainers — no reboring, no plate modification. The oversized tip handles the new hole requirement while the standard shank fits existing hardware.
Engineering Resources
Application Scenarios
Point-larger-than-shank punches solve specific geometric constraints:
Tight Station Spacing
Progressive die layouts where hole diameter exceeds the maximum shank size allowed by station pitch.
The oversize head creates the required hole diameter while the smaller shank fits through the available punch plate spacing. No die redesign needed.
Multi-Diameter Stepped Holes
Applications requiring a larger piercing diameter with a smaller shank to clear adjacent punches or die features.
The head-to-shank diameter ratio allows punching larger features while maintaining clearance to neighboring stations in crowded die layouts.
Retrofit of Existing Dies
Upgrading existing dies where punch plate holes are a fixed size but larger piercing diameters are needed.
Point larger punches fit existing retainer bores while piercing larger holes — avoiding the cost of re-boring punch plates or replacing retainers.
Frequently Asked Questions
What is the maximum point-to-shank ratio available?+
Can point-larger punches be used in standard retainers?+
What applications require a point larger than the shank?+
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