Plastic · Material guide
Custom Delrin (acetal) parts from independent machine shops
Delrin, DuPont's trade name for acetal (POM), is the go-to engineering plastic for gears, bushings, and low-friction parts. It is stiff, strong, wear-resistant, and machines cleanly to tight tolerances. Upload a drawing and hear back from shops that run acetal every day.
STEP · STL · IGES · DWG · DXF · PDF · and more
Uploads are secure & confidential
Delrin shops on OpenSpindle
Real shops that machine Delrin and acetal. See their equipment and talk to the person making your part.
★ Top rated
"Precision Waterjet & CNC Plasma Cutting for Any Material, Any Design."
★ Top rated
"Precision CNC Machining & Fabrication Near Austin - 40+ Years"
"Rapid Prototyping, Digital Manufacturing & CNC Machining Since 1994"
"Multi material experiential and retail fabrication in Brooklyn"
"Precision Waterjet & CNC Cutting in Central Texas"
"Retail store fixtures, POP displays, and architectural millwork built under one roof"
Grades
Delrin and acetal grades shops run most
Acetal comes in two base chemistries plus filled variants. The grade sets strength, chemical resistance, and friction; if yours is not here, ask when you request a quote.
Delrin (POM-H homopolymer)
DuPont's homopolymer acetal. Higher strength, stiffness, and hardness than copolymer, with the best surface finish and creep resistance. Can have a low-density centerline in thick sections. The default when a drawing says "Delrin".
Best for Gears, precision mechanical parts, wear surfaces
Acetal copolymer (POM-C)
The copolymer grade (Delrin is a homopolymer). Slightly lower strength but better resistance to hot water and strong chemicals, and no centerline porosity, so it is preferred for thick sections and food or medical use.
Best for Thick sections, chemical exposure, food-contact parts
Delrin AF (PTFE-filled)
Homopolymer acetal blended with PTFE fibers for a much lower coefficient of friction and better wear life. Costs more and is slightly weaker than standard Delrin. The choice for self-lubricating bearing surfaces.
Best for Bearings, bushings, sliding and low-friction parts
Delrin / acetal, black
Black-pigmented stock, usually UV-stabilized, so it holds up better outdoors and hides handling marks. Mechanically the same as natural. The most common color machined.
Best for Outdoor parts, cosmetic parts, general use
Delrin / acetal, natural
Unpigmented off-white stock. Mechanically identical to black but not UV-stabilized. Common where color does not matter or a light part is preferred.
Best for Internal parts, general mechanical use
Specs
Material properties
Representative values for acetal homopolymer (Delrin). Copolymer and filled grades vary slightly.
| Property | Typical value |
|---|---|
| Density | 1.41 g/cm³ (0.051 lb/in³) |
| Tensile strength | ~10 ksi (70 MPa) |
| Max continuous service temp | ~90 °C (195 °F); higher for short peaks |
| Coefficient of friction / wear | Low friction, excellent wear, self-lubricating |
| Chemical resistance | Good vs fuels and solvents; weak vs strong acids and oxidizers |
| Moisture absorption | ~0.2%, dimensionally stable |
| Machinability | Excellent; machines like brass, holds tight tolerances |
Acetal is stiff, strong, and fatigue-resistant, which is why it replaces metal in gears, cams, and small mechanisms. Its low moisture absorption keeps parts dimensionally stable where nylon would swell.
Stock
Forms we machine it from
Plate & block
Milled housings, manifolds, and prismatic parts from solid.
Round bar
Turned gears, bushings, rollers, and spacers.
Sheet
Routed and cut gaskets, wear strips, and flat parts.
Processes
Manufacturing methods for delrin
The right process depends on part geometry, tolerances, and production volume.
Finishing
Finishes for delrin
Acetal machines to a fine finish and is almost always shipped as-machined. It does not plate, paint, or anodize, so color comes from the stock, not a coating.
As-machined
The standard. Delrin cuts to a smooth, low-friction surface straight off the tool, ideal for gears and bearings where a coating would only add drag.
Natural vs black stock
Choose color at the stock level. Black is usually UV-stabilized for outdoor use; natural is off-white. Both are mechanically identical.
Bead blast
An even matte texture for a uniform cosmetic look. Optional, since the as-machined finish is already clean.
Skip plating and anodizing questions for acetal. If you need a specific color or UV resistance, call it out so the shop pulls the right stock.
Applications
Where delrin parts are used
Delrin shows up wherever a stiff, low-friction, dimensionally stable plastic can replace metal.
Compare
Delrin vs other materials
How Delrin stacks up against the other engineering plastics and metals shops quote most.
Delrin vs Nylon
Nylon →- Delrin is stiffer, more dimensionally stable, and has lower friction
- Nylon absorbs far more moisture, so nylon parts swell and lose tolerance in humid or wet use
- Nylon has better impact resistance and abrasion life in some applications
Choose Delrin for tight-tolerance gears and low-friction parts that must stay dimensionally stable. Choose nylon when impact resistance and toughness matter more than dimensional stability.
Delrin vs PEEK
PEEK →- PEEK handles far higher temperature (continuous ~250 °C vs ~90 °C) and more aggressive chemicals
- Delrin is several times cheaper and machines just as easily
- PEEK is stronger and stiffer, and is used in medical and aerospace parts Delrin cannot reach
Choose Delrin for cost-effective mechanical parts at moderate temperature. Choose PEEK when high heat, chemical exposure, or strength justify the premium.
Delrin vs Aluminum
Aluminum →- Aluminum is far stronger and stiffer and handles much higher temperature
- Delrin is lighter, does not corrode, runs quieter, and is electrically insulating
- Delrin is self-lubricating, so it makes better gears and bearings without added lubricant
Choose Delrin for quiet, low-friction, corrosion-free mechanical parts. Choose aluminum when you need structural strength, stiffness, or heat resistance.
Questions
Frequently asked questions
Delrin is DuPont's trade name for acetal homopolymer (POM-H); acetal is the generic material, which also comes as a copolymer (POM-C). Homopolymer Delrin is stronger, stiffer, and takes a finer finish, but can have a low-density centerline in thick sections. Copolymer resists hot water and strong chemicals better and has no centerline porosity. Both machine the same, so specify which one if it matters to your part.
Get Delrin part quotes
Upload a drawing once and compare quotes from independent shops that machine Delrin and acetal to tight tolerances.
STEP · STL · IGES · DWG · DXF · PDF · and more
Uploads are secure & confidential