What Plastics Are Used In Machine Shops?

Industry Spotlights

By B. Decker  •  Updated August 2026   •  9 min read

Machine shops use engineering plastics, ABS, nylon, acetal (Delrin), UHMW, PTFE, polycarbonate, and PVC among them for bearings, bushings, gears, wear strips, machine guards, and electrical insulation. Each material trades off differently on machinability, wear resistance, and heat tolerance, so the right choice depends on the specific part, not a single "best" plastic.

Ask five machinists which plastic belongs on the shop floor and you'll get five different answers, because the honest answer is "it depends on the part." A wear strip and a precision gear have almost nothing in common as machining problems, and the plastic that's right for one is often wrong for the other. This guide breaks down the materials machine shops actually reach for, what each one is good at, where each one falls apart, and which part of the shop each one tends to end up in.

Why Machine Shops Run on Plastic, Not Just Metal

Metal isn't going anywhere in a machine shop, but plastic solves problems metal creates. A bronze bushing needs grease; an acetal bushing runs dry and doesn't seize when the lubrication schedule slips.

A steel guide rail scores and rusts; a UHMW liner shrugs off the same abrasive load for years without a corrosion concern. Plastic parts cut noise on high-cycle equipment, run lighter for less strain on drive components, and in a lot of cases, cost a fraction of the machined-metal equivalent. None of that means plastic replaces metal everywhere, it means the two materials solve different halves of the same problem.

Quick-Reference Comparison

Figures below are typical for general-purpose grades. Always confirm against the specific manufacturer datasheet for the grade you're ordering — filled, glass-reinforced, and specialty grades shift these numbers meaningfully.

Material Profiles

ABS

ABS is the shop's default when the part just needs to hold a shape and take some abuse without costing much. It machines with low tool wear, thermoforms without drama, and takes an impact without cracking the way a more brittle plastic would. Control panels, machine housings, storage cases, jigs, and prototype fixtures are where it ends up most often. It comes in general-purpose, machine, and fire-rated grades — pick the grade based on what the part actually has to survive, not just what's cheapest on the shelf.

Nylon vs. Acetal: The Bearing and Bushing Decision

These two get compared constantly because they compete for the exact same parts: bushings, gears, wear pads, rollers, and anything replacing a metal bearing surface. Nylon absorbs moisture up to around 8% by weight at saturation and that moisture uptake changes its dimensions and softens it slightly, which sounds like a flaw until you need a part that takes shock loads without cracking.

That toughness is nylon's real advantage. Acetal barely absorbs moisture at all, holds tolerance across humidity swings, and machines cleaner, with small discrete chips instead of the stringy mess softer plastics produce.

If the part sees dynamic impact loads, nylon usually wins. If it has to hold ±0.001″–0.002″ tolerance regardless of shop humidity, acetal is the better bet. Both will lower noise and vibration compared to a metal-on-metal bearing surface, and both eliminate the grease fitting a bronze bushing needs.

UHMW

UHMW is the material you reach for when abrasion, not precision, is the problem. Its wear resistance runs roughly six times that of unfilled nylon, and its coefficient of friction is about as low as any unfilled plastic gets. That's the whole pitch for wear strips, chute liners, guide rails, and star wheels parts that take constant sliding contact and need to survive it for years, not just pass a first inspection.

The trade-off shows up the moment you try to hold a tight tolerance on it. UHMW is soft and deflects away from the cutting tool, so precision machined parts aren't its strength.

It also cold-flows under sustained compressive load and isn't UV-stable outdoors without a stabilized grade. Use it where durability matters more than dimensional precision, not the other way around.

PTFE

Nothing in a machine shop beats PTFE's coefficient of friction, and its chemical resistance covers nearly everything a shop floor throws at it solvents, acids, fuels, you name it. It handles continuous service up to roughly 500°F (260°C), which puts it in a different temperature class than every other material on this list. The catch is machinability.

PTFE is soft enough that it creeps under vice pressure during machining, which makes holding tolerances tighter than about ±0.005″ a genuine fight. It's the right call for seals, gaskets, and low-friction guides. It's the wrong call for anything needing precision fit.

Polycarbonate

Polycarbonate is doing a different job than everything above it on this list — it's not a wear or bearing material, it's a protection material. Machine guards, viewports, face shields, and conveyor guarding are where it earns its keep, because its impact resistance runs roughly 250 times that of standard glass and about 30 times that of acrylic. That's the number that matters when someone's standing in front of the guard while the machine is running. It stays clear enough for an operator to actually see through, handles heat better than acrylic, and flexes under impact instead of shattering.

Rigid PVC

PVC is the budget-conscious, chemically resistant option for fluid handling and electrical work around the shop. It resists corrosion from most common chemicals, comes in sheet and rod stock in gray and white, and fabricates without needing anything exotic in the way of tooling. Valves, fittings, cable insulators, tanks, air scrubbers, and piping are the usual applications. It's not a structural or wear material — it's a workhorse for anything moving fluid or isolating a live conductor.

Beyond the Core Seven

A few more materials show up often enough to mention. PEEK covers the territory none of the above can touch — continuous service near 480°F and strong chemical resistance, at roughly 10–15 times the cost of acetal. That premium keeps it reserved for applications that genuinely demand it. PPS competes in a similar high-heat, high-chemical-resistance niche. Acetal-family PET and PTFE-filled tapes round out most shops' specialty inventory.

Acrylic, by contrast, rarely shows up on the machining side of a shop floor, it's brittle enough that vibration and impact from nearby equipment make it a poor fit for structural or wear parts, even though it's a fine choice for a static viewing window.

Where Plastic Shows Up on the Shop Floor

Plastic isn't a single-part material in a machine shop, it's threaded through almost every moving system. The list below covers where it typically ends up, and which material family usually fills the role:

Bearings & bushings — nylon or acetal
Gears — acetal, nylon
Star wheels & sprockets — UHMW, acetal
Slide pads & wear strips — UHMW
Valve components — PVC, PTFE
Wheels, rollers & pulleys — nylon, UHMW
Manifolds — PVC, acetal
Electrical insulation — PVC, nylon
Seals & gaskets — PTFE

Notice the pattern: every one of these is a moving or wear-facing part. That's not a coincidence. Plastic's real advantage over metal in a machine shop isn't cost, even though it usually is cheaper it's that plastic parts move against each other, and against metal, with less friction, less noise, and no lubrication schedule to maintain.

Frequently Asked Questions

Bottom Line

There's no single best plastic for a machine shop, only the best plastic for a specific part. Acetal and nylon split the bearing and gear work between shock resistance and dimensional stability. UHMW takes the abrasion-heavy jobs nothing else survives. PTFE covers the seals and low-friction points nothing else can match on friction alone. Polycarbonate protects operators where impact resistance is non-negotiable. PVC handles the fluid and electrical work at a price point metal can't touch. Match the material to the failure mode you're actually worried about, and the choice usually gets easier fast.

Related reading: ABS Sheet Guide  •  Acetal Guide  •  Polycarbonate Sheet Guide  •  MRO & Manufacturing Plastics