Material guide
Delrin vs UHMW for Wear Parts
Delrin and UHMW are both slippery, wear-resistant plastics, but one holds tight tolerances and the other shrugs off abrasion and impact. Here's how to choose for bushings, guides, rollers and wear strips.
Choose Delrin (acetal) for precise parts that carry load: bushings, gears, rollers, cams and anything with tight tolerances. Choose UHMW for parts that slide, scrape or take impact: wear strips, guides, liners and bumpers, especially in large sizes where low cost and toughness matter more than precision.
The short version
Both materials are slippery, machine easily and show up all over conveyors and packaging lines. The difference is rigidity. Delrin is hard and stiff, so it holds its shape and tolerances under load. UHMW is softer and much tougher, so it absorbs abrasion and impact that would wear or chip acetal.
| Delrin (acetal homopolymer) | UHMW | |
|---|---|---|
| Tensile strength | ~10,000 psi | ~5,000 psi or less |
| Stiffness | High | Low |
| Machined tolerances | ±0.001–0.002" routinely | Looser; moves with temperature |
| Abrasion resistance | Good | Excellent |
| Impact resistance | Good | Excellent |
| Coefficient of friction | Low | Very low |
| Moisture absorption | Very low (~0.2%) | Near zero |
| Chemical resistance | Good; attacked by strong acids, bases and chlorine | Excellent |
| Max service temp | ~180°F (82°C) | ~180°F (82°C) |
| Relative cost | $$ | $ |
Typical values for unfilled stock shapes. Confirm with the datasheet for your grade.
Load and precision: Delrin's territory
Acetal is one of the most dimensionally stable, easy-to-machine plastics there is. It holds threads, press fits and tight bores, barely absorbs moisture, and doesn't creep much under load. That's why it's the default for bushings and bearings on steel shafts, gears, rollers, cams, valve components and precision fixtures.
UHMW in the same roles tends to deflect, creep out of round under load, and grow or shrink noticeably with temperature.
Abrasion and impact: UHMW's territory
When the job is surviving abuse, UHMW wins. It handles abrasive product sliding across it, chains and belts running on it, and impacts that would crack a stiffer plastic. It's also cheaper per pound and easy to get in big sheets, so long wear strips, chute liners and bumpers are almost always UHMW.
Friction and running dry
Both are self-lubricating and run without grease in most applications. UHMW is a bit slipperier and more forgiving on rough or dirty surfaces. Delrin runs very well against smooth, hardened metal and keeps a consistent fit, which matters more for rotating parts. For heavier loads or higher speeds, ask about PTFE-filled acetal or lubricated UHMW grades.
Food processing and washdown
Both come in FDA-compliant natural grades, and both are common on food and beverage lines. If parts see hot water, steam or caustic and chlorinated sanitizers, UHMW and acetal copolymer generally hold up better than Delrin homopolymer.
When to choose each
Choose Delrin for
- Bushings and bearings on metal shafts
- Gears, sprockets, cams and rollers
- Tight-tolerance machined parts and fixtures
- Threaded parts and press fits
- Parts that carry steady load
Choose UHMW for
- Wear strips, chain and belt guides
- Chute, hopper and bin liners
- Bumpers, guards and impact pads
- Large, low-cost sliding parts
- Harsh chemical or washdown environments
Tip from the counter: on a conveyor, it's common to use both: UHMW for the long wear strips and guide rails, and Delrin for the idler rollers, bushings and small precision parts.
Comparing UHMW with its cheaper cousin? See UHMW vs HDPE.
Common questions
What is stronger, Delrin or UHMW?
Delrin, by a lot. Acetal has roughly twice the tensile strength and several times the stiffness of UHMW, so it carries loads without deflecting or creeping. UHMW is tougher, meaning it absorbs impact and resists abrasion better, but it's soft and will deform under sustained load.
Is Delrin the same as acetal?
Delrin is the brand name for acetal homopolymer. Generic "acetal" usually means acetal copolymer. They're very similar: homopolymer (Delrin) is a bit stiffer and stronger, while copolymer has better chemical resistance and no center porosity in thick rod.
Which has lower friction, Delrin or UHMW?
UHMW generally has the lower coefficient of friction and is more forgiving running dry against itself or on rough surfaces. Delrin also has low friction and runs very well against smooth metal shafts, which is why it's common for bushings and gears.
Can UHMW hold tight tolerances?
Not as well as Delrin. UHMW is soft, moves with temperature (high thermal expansion) and can relax after machining. Expect to hold a few thousandths at best on small UHMW parts, while Delrin routinely holds ±0.001" to ±0.002". If a print calls out tight tolerances, Delrin is the safer material.
Is Delrin food safe?
Natural Delrin and acetal copolymer are available in FDA-compliant grades and are widely used in food equipment. So is natural UHMW. Ask your supplier for a compliance letter for the exact grade, and note that copolymer acetal holds up better to hot water and caustic washdowns.
Values in this guide are typical figures for common unfilled grades, for general comparison only. Properties vary by manufacturer, grade, filler, and shape. Before you specify, buy or machine a material for an application, check the manufacturer's datasheet and the material certifications for the exact grade you're getting, and confirm suitability with your supplier.
Who stocks and machines it
Distributors that stock these materials and shops that machine or fabricate them, from the Stock & Shape directory.
Acetal (Delrin)
- Cope Plastics – Hiawatha Hiawatha, IA
- Interstate Advanced Materials – Portland Portland, OR
- Laird Plastics – Orlando Orlando, FL
- Piedmont Plastics – Westchester Thornwood, NY
- Ehren-Haus Industries Fort Mill, SC
- J & N Metal Products Brazil, IN
- Maximum Industries Irving, TX
- Miles Products Brunswick, OH
UHMW
- Calsak Plastics – Tucson Tucson, AZ
- Laird Plastics – Detroit Shelby Township, MI
- Piedmont Plastics – Dallas Grand Prairie, TX
- Total Plastics – Indianapolis Indianapolis, IN
- CGR Products – Greensboro Greensboro, NC
- Hi Rel Plastics & Molding Riverside, CA
- K&E Plastics Bennington, VT
- Portland Precision Manufacturing Portland, OR