Master knurling patterns with our complete guide to types, grip ratings, design rules, and custom solutions for engineers and machinists.

What Is Knurling

Knurling is a machining process that creates a patterned texture on metal or plastic surfaces. Its main goals are improving grip, enhancing appearance, and helping with assembly by adding surface roughness to otherwise smooth parts.

Here’s why knurling matters:

• Grip: Makes it easier to hold or turn handles, knobs, and tools.
• cURL Too many subrequests.: Adds a professional, industrial look to finished parts.
• Assembly aid: Provides extra surface friction to prevent slipping during installation.

Material Compatibility

Knurling works differently depending on the material. Here’s a simple guide:

Material	Suitability for Knurling	cURL Too many subrequests.
Aluminum	Excellent	Soft, takes patterns well
Steel	Excellent	Durable, great for grip
cURL Too many subrequests.	Good	Shiny finish, can deform easily
Polymers	Variable	Depends on hardness, watch for melting

CNC vs Manual Knurling

Choosing between manual and CNC knurling depends on your needs:

• CNC Knurling
  • Pros: Consistent pattern, quick set-up, repeatable quality
  • Cons: Higher upfront cost, less flexible on small runs
• Manual Knurling
  • Pros: Low cost, flexible for custom jobs, works well for low volume
  • Cons: Inconsistent patterns, slower, operator skill matters

Both have their place depending on your part volume, tolerance needs, and budget.

In short, knurling adds function and style without much fuss, and picking the right method and material makes all the difference.

6 Core Knurling Patterns Visual-First Breakdown

Here’s a quick look at the six main knurling patterns, their pitch, grip rating, best uses, and how vast tooling options support them.

Straight Pattern

• Pitch: Medium to coarse
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• Best Use: Ideal for grips that need a firm hold without being too aggressive—think tool handles or knobs.
• Vast Tooling: Easily available, simple setup, great for high-volume runs.

Diamond Pattern

• Pitch: Fine to medium
• Grip Rating: High
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• Grip Rating: Moderate to high
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• Grip Rating: High
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When designing knurling, stick to these straightforward guidelines to get consistent, high-quality results:

• Pitch depends on material hardness and diameterSofter materials and smaller diameters call for a finer pitch to avoid tearing. Harder materials can handle coarser pitches. Adjust pitch accordingly to balance grip and tool wear.
• Knurl depth should be about 0.4 times the pitchFollow ISO 13443 standards for depth: the depth of the knurl should be roughly 40% of the pitch. This keeps the pattern effective without damaging the surface.
• Tool overlap strategy: 2 pass vs 3 passUse 2 passes for faster production and moderate surface finish where speed matters.
  Opt for 3 passes when you need sharper, cleaner edges and smoother, more uniform patterns.Tolerance stack-up mattersEnsure your design accounts for dimensional tolerances. Use a tolerance stack-up calculator or interactive widget to predict cumulative variations and avoid fit or function issues.

Following these rules guarantees knurling that looks good, performs well, and lasts longer without costly rework.

Industry Applications Matrix

Knurling patterns show up across different industries, each with specific benefits and proven ROI. Here’s a quick look at how some common patterns deliver real value:

Firearms – Diamond Pattern

• Used on AR-15 grip surfaces
• Boosts torque control and grip stability
• Results in better handling under wet or gloved conditions

Medical – Barley Pattern

• Applied to syringe plungers and handheld tools
• Increases slip resistance without extra force
• Helps reduce user fatigue during repetitive tasks

Automotive – Helical Pattern

• Common on shift knobs and control levers
• Speeds up assembly by improving tool engagement
• Enhances overall driver grip comfort, especially during longer drives

Each pattern fits specific material and ergonomic needs, making knurling more than just an aesthetic choice—it’s a functional upgrade that pays off with better safety, performance, and efficiency.

Common Knurling Failures and Fixes

Knurling can sometimes go wrong, but most issues have straightforward fixes:

• Peeling: If the knurl pattern lifts or peels, increase the form roll pressure between 8% and 12%. This extra pressure helps the tool bite deeper into the material for a clean, lasting pattern.
• Uneven Depth: Uneven knurl depth often points to the wheel not running true. Check the wheel’s concentricity and make sure it’s within 0.01 mm tolerance. Proper alignment prevents inconsistent patterns.
• Surface Cracking: When knurling hardened alloys like 6061 T6 aluminum, surface cracking can happen. A simple fix is to pre-anneal the material. This softens the surface and reduces cracking risks during knurling.

Addressing these common problems early ensures a quality knurl finish that holds up in everyday use.

How to Specify Knurling on Drawings ASME Y14 5

When adding knurling to your drawings, following ASME Y14.5 standards ensures everyone reads it right the first time. Here’s a quick guide to get your knurling callouts clean, clear, and ready for production.

Callout Syntax Examples

Use simple, standardized notes like this:

• KNURL DIAMOND MEDIUM R0.8
  This means a diamond knurl with a medium pitch and a radius of 0.8mm.

Keep it short but descriptive enough for tooling and operators to understand.

GD&T Integration for Knurling

If you want tighter control, incorporate profile tolerances from GD&T:

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Ready to see how custom knurling can improve your project? Get your free pattern sample today and experience the difference firsthand.

Knurling Patterns FAQ

Here are quick answers to common questions about knurling patterns:

Best knurling pattern for grip on aluminum

Diamond knurling is the top choice for aluminum. It offers excellent slip resistance without damaging the softer metal. The crisscross pattern grips well and works for everything from tool handles to knobs.

Can you knurl titanium?

Yes, titanium can be knurled, but it’s harder than aluminum or brass. You’ll need sharp, high-quality knurling tools and slower feed rates to avoid tool wear and work hardening the surface. Manual or CNC knurling works with proper setup.

Difference between raised vs depressed diamond knurl

• Raised diamond knurls leave a pattern that sticks out from the surface, giving a tactile grip feel.
• Depressed diamond knurls press inward, creating indentations that are less aggressive but still improve grip.
  Raised is better for maximum grip, while depressed is often preferred when avoiding surface damage matters.

If you want help choosing the right pattern or specifying knurl details, check out our detailed guides and knurling design rules.