Delrin vs Nylon for Custom Machined Parts: Which Engineering Plastic Is Right for Your Application? 

You often see Delrin vs Nylon for custom machined parts listed as material options for the same components, yet they behave very differently once they’re in service. That leaves many engineers wondering how to choose between them without trial and error. This guide compares both materials across the properties that matter most so you can make the right decision the first time. 

What Are Delrin and Nylon, and Why Are They Used in Machined Parts? 

Delrin (acetal homopolymer / POM‑H) is a semi‑crystalline thermoplastic known for high stiffness, low friction, and excellent dimensional stability. It’s widely used for Delrin machined components that need precision and smooth motion. 

Nylon (polyamide, including PA6 and PA66) is a tough, wear resistant thermoplastic with strong fatigue resistance and a wide range of grades. It’s often selected for parts that need impact strength or vibration dampening. 

Both materials are chosen over metal because they offer: 

• Lower weight 

• Natural self lubrication 

• Corrosion resistance 

• Easy machinability 

These advantages make them popular engineering plastic for custom parts across many industries. 

You’ll see them used in bushings, gears, rollers, spacers, and many custom plastic parts for industrial use where performance and reliability matter. 

How Do Delrin and Nylon Compare on Key Mechanical Properties? 

Delrin and Nylon share some similarities, but their mechanical behavior differs enough to affect performance in critical ways. This is especially important when comparing acetal vs nylon machined parts or evaluating Delrin vs nylon bearings for your design. 

Tensile Strength and Stiffness 

Delrin is stiffer and holds its shape better under load. Nylon is more flexible and absorbs impact without cracking. 

Hardness and Wear Resistance 

Delrin performs well in abrasive sliding conditions and maintains a consistent friction profile. Nylon handles cyclic fatigue better and can take repeated impacts. 

Compressive Strength 

This matters for bushings, bearings, and load bearing surfaces. Delrin typically offers higher compressive strength, making it a better fit for precision bearing surfaces. 

Delrin vs Nylon Mechanical Comparison Table 

Property	Delrin (Acetal/POM‑H)	Nylon (PA6/PA66)
Tensile Strength	High	Moderate–High
Flexural Modulus	Very high	Moderate
Hardness (Rockwell)	M80–M90	R110–R120
Max Continuous Service Temp	~90–100°C	~120°C
Friction Coefficient	Very low	Low–moderate
Moisture Absorption	0.2–0.5%	Up to 7%
Machinability Rating	Excellent	Good–fair

These differences matter when selecting the best plastic for machined bearings or comparing low-friction engineering plastics for sliding components. 

Which Material Handles Moisture and Chemicals Better? 

Moisture is one of the biggest dividing lines between Delrin and Nylon, especially when evaluating moisture resistant plastic for machined parts. 

Nylon’s Hygroscopic Nature 

Nylon absorbs moisture from the air and from direct water exposure. This causes: 

• Dimensional changes 

• Swelling 

• Loss of tight tolerances 

• Reduced stiffness 

This can lead to early failure in precision parts. 

Delrin’s Moisture Advantage 

Delrin absorbs very little moisture, so it maintains: 

• Shape 

• Strength 

• Tolerances 

This makes it ideal for humid, wet, or washdown environments. 

Chemical Resistance 

• Both resist oils, fuels, and many solvents. 

• Delrin performs better in acidic environments. 

• Nylon performs slightly better in some alkaline conditions. 

These differences align with the typical comparison of acetal homopolymer vs polyamide in industrial applications. 

Practical Guidance 

Choose Delrin for: 

• Outdoor equipment 

• Food processing machinery 

• Washdown environments 

Choose Nylon when: 

• Chemical exposure is controlled 

• Moisture is not a concern 

Which Is Easier to Machine to Tight Tolerances? 

Delrin 

Delrin is one of the easiest engineering plastics to machine. It: 

• Cuts cleanly 

• Produces crisp edges 

• Holds tight tolerances 

• Causes minimal tool wear 

This makes it ideal for precision Delrin machined components and custom plastic parts for industrial use. 

Nylon 

Nylon is machinable, but it requires more care: 

• It absorbs coolant and can expand 

• Pre drying stock is recommended 

• Chips tend to be stringy 

• Heat buildup can cause warping 

Surface Finish 

Delrin typically produces a smoother finish in CNC milling and turning. 

When Nylon Still Wins 

If your part needs toughness more than precision—like gears, cams, or impact‑loaded components—Nylon may still be the better fit. 

How Do They Perform in Bearing and Bushing Applications? 

Both materials are used for nylon bushings vs Delrin bushings, but their performance differs depending on load, speed, and environment. 

Self Lubrication 

Both offer low friction, but Delrin’s friction coefficient is lower and more consistent. 

Load and Speed 

• Delrin is preferred for lighter loads at higher speeds. 

• Nylon handles heavier intermittent loads and shock better. 

Temperature Limits 

• Delrin: ~90–100°C continuous 

• Nylon (PA66): ~120°C continuous 

Noise and Vibration 

Nylon’s elasticity helps dampen vibration, which can reduce noise in some assemblies. 

These differences matter when selecting low-friction engineering plastics or choosing the best plastic for machined bearings. 

Which Engineering Plastic Should You Choose for Your Application? 

Here’s a simple decision guide for Delrin vs Nylon for custom machined parts. 

Choose Delrin for: 

• Tight tolerance parts 

• Humid or wet environments 

• Food processing equipment 

• Precision sliding components 

• Outdoor machinery 

• Stable, repeatable performance 

Choose Nylon for: 

• Impact resistant parts 

• High temperature environments 

• Heavy intermittent loads 

• Cost sensitive, high volume production 

• Parts where vibration dampening matters 

Specialty Grades to Consider 

• Glass‑filled Nylon for added stiffness 

• Oil‑filled Delrin for enhanced lubrication 

• Cast Nylon (MC901) for large or heavy duty parts 

These options help you fine tune performance when comparing acetal vs nylon machined parts or evaluating Delrin vs nylon bearings. 

Why Source Custom Machined Plastic Parts from Bearings Direct? 

Bearings Direct supports engineers, machinists, and OEM buyers with: 

• A wide range of Delrin and Nylon stock shapes (rod, sheet, tube) 

• Custom machined bushings, sleeves, spacers, and wear pads 

• Expert material selection guidance 

• Fast turnaround for OEM and MRO procurement 

• Reliable supply and consistent quality 

Whether you need a single prototype or a full production run, you get parts that meet your exact specifications. 

Ready to Order Custom Machined Parts in Delrin or Nylon? 

If you’re ready to move forward, Bearings Direct can help you source the right material and get your parts machined to print. Explore the custom parts catalog, send your drawings, and get fast turn quotes backed by expert guidance. 

FAQ: Delrin vs Nylon for Custom Machined Parts 

1. Is Delrin stronger than Nylon?

Delrin is stiffer, while Nylon is tougher and more impact resistant. 

2. Does Nylon absorb moisture?

Yes. Nylon can absorb up to 7% moisture, which affects dimensions and stiffness. 

3. Is Delrin good for bearings and bushings?

Yes. Delrin’s low friction and stability make it ideal for dry-running bearings. 

4. Which material do machines better?

Delrin machines cleaner and holds tighter tolerances. 

5. Is Nylon cheaper than Delrin?

Generally yes, especially in high volume applications. 

6. Which material is better for outdoor use?

Delrin performs better because it resists moisture and dimensional changes. 

7. Can both materials be used for gears?

Yes, but Delrin is preferred for precision gears; Nylon works well for impact loaded gears. 

8. Which material handles heat better?

Nylon (PA66) has a higher continuous service temperature than Delrin. 

9. Do both materials offer self lubrication?

Yes, but Delrin’s friction profile is more consistent over time. 

10. Which material is better for food processing equipment?

Delrin is typically preferred due to its moisture resistance and dimensional stability.