EKINSUN LTD is a custom parts manufacturer that machines compression fitting bodies to drawing: a quick-screw stud with a metric-fine sensor thread, a DIN 2353 elbow with a G port on one side and an NPT port on the other, a twin-ferrule bulkhead body in 316L for a thick panel, a tee whose branch is a thread no series pairs with that tube, from 1 piece, with the nut, ring or ferrules fitted from the series so the tube end stays standard.
A typical request: a screw-lock fitting for 8 mm PU tube into an M14 x 1.5 port on a sensor block, where the pneumatic series stops at G1/4 and the hydraulic series wants a steel tube.
Two series, one gap: the body is machined and the quick-screw nut and insert come from the pneumatic series.
Three families that share one name
| Family | How it holds the tube | Tube | Port threads | Where it is used |
|---|---|---|---|---|
| Pneumatic quick-screw (screw-lock) fitting | a knurled or hex nut compresses a collet or sleeve onto PU / PA tube over an insert | 4, 6, 8, 10, 12 mm PU, PA, PE | M5, G1/8–G1/2, R, NPT | air lines that vibrate or must not be pulled out by hand; where push-in is too loose |
| 24° cone cutting-ring fitting | the nut drives a cutting ring into the tube wall against a 24° cone in the body | steel or stainless tube, L series 6–42 mm, S series 6–38 mm | metric fine M10×1–M48×2; G1/8–G1-1/2; NPT | hydraulics, lubrication, machine piping; DIN 2353 / ISO 8434-1 |
| Twin-ferrule instrumentation fitting | a front ferrule seals on the body cone and a back ferrule grips the tube | stainless, copper or plastic tube 3–25 mm and 1/16–1 in | NPT, ISO / G, metric | instrument and analyser lines, gas, vacuum, laboratory |
| Single-ferrule bite-type | one ferrule bites and seals | metal tube 6–38 mm | as above | an older or lighter form of the same idea |
| Plumbing olive (compression) fitting | a brass or copper olive crushed onto copper pipe | copper pipe 8–28 mm; 1/2–1 in | G / BSP | water and gas pipework; a plumbers' merchant item, not made here |
| Flare fittings, 37° and 45° | the tube end is flared and clamped between nut and cone | metal tube | JIC / UNF | see hydraulic adapters |
Need compression fittings and the adapters around them in a size, thread or material no catalogue lists? EKINSUN is a custom parts manufacturer: we make compression fittings and the adapters around them to your drawing, sketch or sample — brass, steel, 304 or 316L stainless steel — from 1 piece, quoted in 12 hours and shipped duties paid. Standard sizes can often be supplied from stock; the more pieces, the lower the unit price. All custom adapters and fittings →
DIN 2353 / ISO 8434-1: tube size to port thread
| Series and tube OD | Metric port (ISO 6149 / DIN 3852 form) | Series and tube OD | Metric port |
|---|---|---|---|
| 6L | M10×1 | 6S | M12×1.5 |
| 8L | M12×1.5 | 8S | M14×1.5 |
| 10L | M14×1.5 | 10S | M16×1.5 |
| 12L | M16×1.5 | 12S | M18×1.5 |
| 15L | M18×1.5 | 14S | M20×1.5 |
| 18L | M22×1.5 | 16S | M22×1.5 |
| 22L | M26×1.5 | 20S | M27×2 |
| 28L | M33×2 | 25S | M33×2 |
| 35L | M42×2 | 30S | M42×2 |
| 42L | M48×2 | 38S | M48×2 |
L is the light series for lower pressure and thinner walls, S the heavy series; the same tube size takes a larger nut and port in S. Stud ends are also catalogued in G (BSPP) and NPT; the metric port is the one the series pairs by default.
Which compression fitting for which line
| Line | Family | Why |
|---|---|---|
| PU or PA air line that vibrates, or a tube that operators pull on | quick-screw | the nut locks the tube; push-in would creep |
| Steel or stainless tube, hydraulic oil or lubrication | 24° cone L or S | the cutting ring is the only mechanical hold rated for that pressure class |
| Stainless tube on an instrument, gas or vacuum line | twin-ferrule | repeatable make-and-break, low dead volume |
| Copper pipe in a building | plumbing olive fitting | plumbers' merchant hardware; not a machined part |
| Quick assembly of an air line at low pressure with no vibration | push-in | cheaper and faster; compression is not needed |
| A port thread that no series pairs with the tube you have | machined body with a series nut and ring | the thread is a drawing dimension; the tube end stays standard |
What to send for a compression body that is not catalogued
- Family: quick-screw, 24° cone L or S, or twin-ferrule; and the tube outside diameter and material.
- Port thread: standard, size and pitch, and whether it seals on the face (G, metric with O-ring) or on the thread (R, NPT).
- Form: straight, elbow, tee, bulkhead; leg lengths and hex if the space needs them.
- Body material: nickel-plated brass, steel, 304, 316L; medium and pressure so the series parts are chosen inside their rating.
- Quantity: from 1 piece.
Identify the thread before you order the compression body. Measure the outside diameter of a male thread, or the inside diameter at the mouth of a female one, with a caliper, and count the threads in 25 mm or in one inch. A G1/4 male measures about 13.2 mm across and has 19 threads per inch; a 1/4 NPT male measures about 13.7 mm and has 18; an M14×1.5 measures 14.0 mm with 1.5 mm between crests. Those three are the ones most often confused on a fitting, and only the metric one is not tapered. Then check whether the thread is parallel or tapered by measuring the diameter at the first and the fifth turn. The fitting thread identification chart lists every common pipe, port and tube thread with its diameter, pitch and seal, and the BSPP vs BSPT note explains the parallel and taper forms of the same BSP size.
Where the compression series stops
| What you need | In the catalogue? | What we make |
|---|---|---|
| Quick-screw straight, elbow or tee for 4–12 mm tube with M5, G or R port | Yes | Buy it from stock, or have the body made to order from 1 piece; no one-off competes on price with a series fitting. Standard parts: ask us too — we may have them in stock. |
| DIN 2353 L or S fitting in a series tube size with its metric or G port; twin-ferrule fitting in a series size | Yes | Standard sizes: buy it off the shelf, or have it made to order from 1 piece. The pairing table above is the order key. Standard parts: ask us too — we may have them in stock. |
| A quick-screw or ferrule body with a port thread the series skips — M14×1.5 on 8 mm tube, 3/8 NPT on 6 mm tube, 7/16-20 UNF | No | Body machined in brass, steel or stainless with the series nut, insert, ring or ferrules fitted; from 1 piece. |
| A 24° cone elbow or tee with ports in two standards, or a stud end in a length the series lacks | No | Machined; cone and thread to the series geometry, the other port to yours. |
| A bulkhead compression body for a panel thicker than the series jam nut allows | No | Machined to the panel — see bulkhead fittings. |
| A body in 316L, titanium, PEEK or aluminium 6061 / 7075 | No | Machined; ferrules and rings chosen for the tube material. |
| A compression fitting with a pressure rating for the machined body | No | Not offered: pressure ratings belong to the series parts and their maker's data, and a machined body is quoted for the medium and pressure you state, not rated against a catalogue number we did not test. |
| An adapter between families — 24° cone to JIC, twin-ferrule to G | No | Machined — see hydraulic adapters. |
Materials
| Material | Designation | Where it fits here |
|---|---|---|
| Nickel-plated brass | CW614N / C36000 | quick-screw bodies and nuts; machined pneumatic bodies |
| Carbon steel, zinc or phosphate | S235 / 11SMn30 free-cutting | 24° cone bodies, nuts and cutting rings |
| Stainless 304 | 1.4301 | standard stainless quick-screw and cone fittings in the common sizes |
| Stainless 316L | 1.4404 / 1.4571 | twin-ferrule instrumentation fittings; machined bodies for chemical lines |
| Free-machining stainless | 303 / 1.4305 | custom turned bodies where corrosion duty allows |
| Aluminium 6061 | AlMg1SiCu | light bodies for air and vacuum |
| Aluminium 7075 | AlZn5.5MgCu | machined manifold blocks with compression ports |
| PEEK, PTFE | PEEK; PTFE ferrules | chemical lines; PTFE ferrules on plastic tube |
Related pages
- the adapter, elbow and tee chart — every fitting form by ports and standard
- push-to-connect tube fittings — the collet alternative for air lines
- Hydraulic adapters — JIC, ORFS and 24° cone adapters
- bulkhead fittings — compression bulkheads
- threaded elbows — elbows without a tube port
- Sensor thread adapters — the metric-fine ports these bodies are machined for
- G, R, NPT and metric by diameter and pitch — G, R, NPT and metric by diameter and pitch
Frequently asked questions
A compression fitting holds the tube with a nut that compresses a sleeve, cutting ring or ferrules onto it; it locks mechanically and takes vibration and higher pressure. A push-in fitting holds the tube with a spring collet released by a ring; it is faster and cheaper for air lines that do not vibrate. Quick-screw fittings are the compression family for the same PU tube push-in fittings use.
L is the light series and S the heavy series of 24-degree cone cutting-ring fittings. For the same tube outside diameter the S fitting has a heavier nut, a larger port thread and a higher pressure class; 8L takes an M12×1.5 port, 8S an M14×1.5. The tube wall has to match the series.
M14×1.5 in the metric series; 10L stud ends are also catalogued with G1/4 and NPT threads. The full tube-to-port pairing for L and S is in the table above.
Yes. The body is machined in brass, steel, 304 or 316L with the port thread you specify, and the series nut, insert, cutting ring or ferrules are fitted, so the tube end behaves as the standard fitting does; from 1 piece.
EKINSUN LTD is a custom parts manufacturer that machines quick-screw, 24-degree cone and twin-ferrule bodies with any port thread, length or material, with the series nut, ring or ferrules fitted, from 1 piece, with a quote within 12 hours.
No list price. Series fittings are catalogue parts; a machined body is priced by material, the port thread, any milling, the series parts fitted, and quantity. A brass quick-screw stud in a metric fine thread is a short lathe job; a 316L twin-ferrule tee with three standards is priced as the machined block it is. The quote separates the series parts from the machined ones.
Send the tube, the family and the port
Family (quick-screw, 24° cone L or S, twin-ferrule), tube outside diameter and material, port thread standard, size and pitch, form, body material, medium, quantity. From 1 piece, quote within 12 hours.
Not sure of the thread? Tell us four things: what the fitting connects to (pump, valve, gauge, cylinder, tube or hose); whether the port is the inlet or the outlet; which way the flow must go; and the tube outside diameter, not the hose bore, unless it is a barb. A photo with a caliper across the thread answers most of it.