A plastic fastener insulates, does not corrode, weighs a fraction of steel and is invisible to a magnet. It also creeps, softens with heat and holds a tenth of the load, so it is chosen for what it keeps apart, not for what it clamps. The catalogue stocks nylon in every common form, PC in a few and PEEK in the small sizes; a PEEK nut above M10, a PTFE washer of an odd size or a nylon standoff longer than 60 mm is the part that gets machined.
EKINSUN LTD is a custom parts manufacturer that machines plastic fasteners to drawing: PEEK and PTFE screws and nuts above the stock sizes, nylon and POM standoffs to length, insulating washers and bushes to your bore and outside diameter, glass-filled or conductive grades. The plastic table below gives the property each grade is chosen for; the stock table is read from a 2026 catalogue; the negative-space table marks the border.
"M12 PEEK nuts for a 200 degree oven fixture. Stock PEEK stops at M10 and nylon melts."
Temperature and size are where plastic fasteners leave the shelf.
| Plastic | Chosen for | Continuous service, approx. | Watch | Stock parts |
|---|---|---|---|---|
| Nylon 66 (PA66) | toughness, low cost, insulation | up to about 100 °C | absorbs moisture and swells; creeps under load | screws, nuts, washers, standoffs, rivets, clips |
| Polycarbonate (PC) | transparency, impact strength | up to about 120 °C | cracks with some solvents and oils | transparent screws and nuts M2–M10 |
| PEEK | heat, chemicals, strength, cleanliness | up to about 250 °C | cost; the strongest plastic fastener | screws M1.4–M10, nuts M4–M10, washers M2–M20 |
| PTFE | chemical inertness, low friction, temperature | up to about 260 °C | soft; cold-flows under load | washers; machined parts to order |
| POM (acetal) | stiffness, low friction, dimensional stability | up to about 100 °C | not for hot or wet-alkaline service | plungers, spacers; machined parts to order |
| PVC | cost, chemical resistance | up to about 60 °C | soft; low temperature limit | soft and hard washers M1.2–M20 |
| Silicone, EPDM, NBR, FKM | sealing | silicone to about 200 °C | not fasteners; seals under them | O-rings M3–M100, silicone washers and pads |
| Fibre, mica, ceramic | electrical insulation at temperature | mica and ceramic to several hundred °C | brittle | insulating pads for TO-220 / TO-3P, fibre washers M2–M20 |
Service temperatures are indicative continuous values for unfilled grades; short peaks and filled grades differ. A plastic fastener under load is derated with temperature.
| Family | Stock range | Plastic and colour | Notes |
|---|---|---|---|
| Phillips pan and countersunk screws | M2–M8 | nylon 66 white and black; PC transparent M2–M6; PEEK M1.4–M8 | ISO 7045 / 7046 forms |
| Hex head screws | M3–M12 | nylon white and black; PEEK M3–M10 | — |
| Socket cap and countersunk socket screws | M3–M12 | nylon; PEEK M2–M10 | — |
| Slotted set screws | M3–M12 | nylon; PEEK M3–M6 | — |
| Slotted pan and cheese head screws | M2–M10 | PEEK | — |
| Hex nuts | M2–M20 | nylon white and black; PC M2–M10; PEEK M4–M10 | — |
| Flange, wing and cap nuts | M3–M12; M3–M12; M3–M20 | nylon | — |
| Protective nut caps | M3–M24 | PE in white, black, grey, blue, red, yellow | cosmetic and finger protection |
| Flat and thin washers | M1.4–M20; Ø2–Ø24 | nylon in white, black, blue, red, yellow; PEEK M2–M20; PVC M1.2–M20 | — |
| Shoulder (T-type) insulating bushes | TW/2 – TW/1618 | nylon | isolate a screw from a panel |
| Hex standoffs, male-female and female-female | M2–M6, lengths to 60 mm | nylon black and white | — |
| Round spacers and tubes | Ø4–Ø18 | nylon, ABS, natural | — |
| PCB supports, snap-in and screw-lock | 1.6–36 mm | nylon | MAD, MCS, SS, RC, AS, LCF, PS series |
| Push rivets, snap rivets, panel clips | 3–19 mm | nylon | R2024–R6080; RC M3–M19 |
| Cable-tie mounts, cable clamps, clips, grommets, hole plugs | various | nylon; PE | cable management |
| O-rings and gaskets | M3–M100 | NBR, FKM, silicone | sealing under plastic and metal fasteners |
Read the pitch before you order the plastic nut. Lay a steel rule along ten thread crests and divide by ten: 10 mm over ten pitches is a 1 mm pitch (M6 coarse), 12.5 mm is M8 coarse, 15 mm is M10 coarse, 17.5 mm is M12 coarse. A reading that is not a round number of millimetres is an inch thread, and a reading that is shorter than the coarse pitch for that diameter is a fine thread. If diameter, pitch and the size range in the table all agree, buy the stock part. If any of the three is off the shelf, that is the one we make. The full measuring routine, including the inch traps →
| What you need | In the catalogue? | What we make |
|---|---|---|
| Nylon screws M2–M12, nuts M2–M20, washers M1.4–M20, standoffs M2–M6 to 60 mm | Yes | Buy it from stock. No one-off competes with a moulded nylon fastener. |
| PEEK screws M1.4–M10, PEEK nuts M4–M10, PEEK washers M2–M20; PC screws and nuts M2–M10 | Yes | Stocked; buy it. |
| PEEK screws or nuts above M10, or in a fine or inch thread | No | Machined from PEEK rod to your reading, from 1 piece. |
| PTFE, POM or PVDF screws, nuts, washers and bushes in any size | No | Machined from rod or sheet; PTFE sections sized for cold flow. |
| A nylon or POM standoff longer than 60 mm, or in an odd thread combination | No | Machined to length. |
| An insulating washer or bush to a bore and outside diameter the stock does not carry | No | Turned or cut from nylon, PEEK, PTFE, fibre or mica sheet. |
| A glass-filled, carbon-filled or conductive (ESD) grade | No | Machined from the filled grade the drawing names. |
| A plastic fastener for a preloaded or hot structural joint | No | Not offered: we quote the part in 304, 316L, brass or aluminium 6061 / 7075 with an insulating washer or bush beside it, and say why — see brass fasteners. |
| Material | Designation | Where it fits here |
|---|---|---|
| Nylon 66 | PA66, unfilled and 30 % glass-filled | stock fasteners; machined standoffs and bushes |
| Polycarbonate | PC | transparent fasteners; machined covers |
| PEEK | PEEK, natural and glass-filled | high-temperature and chemical-duty fasteners, machined above M10 |
| PTFE | PTFE | washers and bushes machined to size |
| POM | POM-C | machined spacers and plungers |
| Stainless 304 | 1.4301 / A2 | the metal partner when load or heat exceeds the plastic |
| Stainless 316L | 1.4404 / A4 | as above, for chemical service |
| Aluminium 6061 | AlMg1SiCu | light metal standoffs where nylon creeps |
| Aluminium 7075 | AlZn5.5MgCu | the hard light alloy beside PEEK in instrument work |
| Brass | CW614N | the conductive partner |
About a tenth of a steel screw of the same size, and less as it warms or absorbs moisture. Nylon fasteners are chosen to insulate, isolate or avoid corrosion and magnetism, and the joint is designed around that; where the joint needs preload, the plastic part becomes a washer or a bush beside a metal screw.
About 250 °C continuous for unfilled PEEK, which is why PEEK is the plastic fastener for ovens, autoclaves and chemical plant; nylon 66 is limited to about 100 °C and polycarbonate to about 120 °C.
Washers are stocked in PTFE and PEEK; PTFE screws, nuts and bushes are machined to order because PTFE cold-flows and the section has to be sized for the load.
Yes. PEEK screws, nuts and standoffs above the stock sizes, in any pitch, are machined from natural or glass-filled PEEK rod from 1 piece.
EKINSUN LTD is a custom parts manufacturer that machines fasteners, standoffs, washers and bushes in nylon 66, PC, PEEK, PTFE and POM, unfilled or filled, in any thread and size, from 1 piece, with a quote within 12 hours.
No list price; PEEK rod is the main driver, then the thread and features, then quantity. A batch of nylon standoffs to length is a short job; a single M12 PEEK nut is priced by the rod it comes from and the lathe time. The quote states the drivers.
Plastic or the property that picks it, thread and pitch or bore and outside diameter, length, temperature and load, colour, quantity. From 1 piece, quote within 12 hours.
Plastic fasteners, standoffs, washers and bushes machined to thread, size, plastic and temperature — from 1 piece, quote in 12 hours.