EKINSUN LTD is a custom parts manufacturer that machines threaded tees and crosses to drawing: an MFF tee with a male run end for a pump outlet and two female ports for the line and a gauge, a tee with three ports in three standards, a two-step reducing tee, a tee with a metric-fine branch for a sensor, a cross from square bar, from 1 piece in brass, 304, 316L or steel.
A typical request: G3/8 male into the pump, G3/8 female out to the regulator, and a 1/4 NPT female on the branch for the gauge — three ports, two standards, no catalogue.
That is an MFF tee with a mixed branch, and it is what a pump outlet usually needs.
Tees named by their ports
| Notation | Ports (run end, run end, branch) | Also called | Where it is used |
|---|---|---|---|
| FFF | female, female, female | female tee, equal tee, pipe tee | joining three male pipe ends or nipples |
| MFF | male, female, female | male-female-female tee, one male two female tee, branch tee, street tee | screwed into a pump, valve or manifold port; the line and a gauge or second line on the females |
| FMM | female, male, male | female-male-male tee, one female two male tee | between two female ports with a female branch |
| MMM | male, male, male | male tee | three female ports around it; rarely catalogued |
| FFM | female, female, male (branch male) | male branch tee | a male branch into a port with the run on the line |
| Reducing tee | any, branch smaller | reducing branch tee | a smaller line or gauge off a larger run |
| Gauge tee | MFF or FFF with a G1/4, G1/8 or 1/4 NPT branch | pressure gauge tee, gauge branch fitting | adding a gauge to a pump outlet or a line |
| Cross | four ports | four-way, cross union | two lines crossing, or a run with two branches |
Run ends first, branch last: a G1/2 × G1/2 × G1/4 tee has a 1/4 branch. When the run ends differ, say which is which.
Need threaded tees in a size, thread or material no catalogue lists? EKINSUN is a custom parts manufacturer: we make threaded tees to your drawing, sketch or sample — brass, 304 or 316L stainless steel — from 1 piece, quoted in 12 hours and shipped duties paid. If the size is standard, ask anyway — it may be in stock, and the unit price drops as the quantity rises. All custom adapters and fittings →
Standard sizes and ranges
| Thread standard | Standard forms | Catalogue sizes | Common materials |
|---|---|---|---|
| G (BSPP) female, R (BSPT) male | EN 10241 (steel), ISO 49 / DIN 2950 (malleable), brass fitting forms | FFF 1/8–1 in; MFF 1/4–3/4 in; reducing FFF with one-step branch | brass, nickel-plated brass, 304, 316, malleable iron |
| NPT | ASME B16.11 (forged), B16.15 (cast brass), B16.3 (malleable) | FFF 1/8–1 in; larger in iron and forged steel | brass, 304, 316, forged steel |
| Metric fine | maker series; DIN 3852 port forms | hydraulic tees M10×1–M22×1.5, one standard per tee | steel |
| Crosses | EN 10241 / ASME B16.11 forms | FFFF 1/4–1 in | brass, 304, iron |
| Mixed standards, two-step reductions, MMM | none | not catalogued | machined |
The tee on a pump outlet
| Position | Port | What sits there | Tee port |
|---|---|---|---|
| Run end 1 | male, the pump outlet thread (often G3/8 or G1/2 on small pumps) | screws into the pump | M |
| Run end 2 | female, the line size | regulator, valve or the pipe onward | F |
| Branch | female, G1/4 or 1/4 NPT | pressure gauge, or a second line | F |
| Result | MFF tee, often with a mixed branch | one part instead of nipple + tee + bushing | machined when the standards differ |
A pump outlet rarely ends with the tee: after it come a regulator connection, a 90° elbow and a tube fitting. The pump fittings page walks that chain port by port; the tee is the part most often machined because it is the one with three chances to be off the shelf.
What to send for a tee that is not catalogued
- All three ports in order: run end, run end, branch; male or female; standard, size and pitch; parallel or tapered.
- Centre-to-end lengths if the tee must fit a space, and which port must face which way.
- Hex or flats, and the bore if flow matters.
- Material and seal: brass, 304, 316L; bonded washers, O-rings, tape or machined seats.
- Quantity; a single tee for a pump that is stopped is a normal order.
Identify the thread before you order the tee. 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 tee catalogue stops
| What you need | In the catalogue? | What we make |
|---|---|---|
| FFF tee, one standard, one size, 1/8–1 in in brass, 304 or iron | Yes | Buy it from stock, or have it made to order from 1 piece. No one-off competes on price with a forged or cast tee. Standard parts: ask us too — we may have them in stock. |
| MFF tee 1/4–3/4 in in one standard, or a reducing FFF with a one-step branch | Yes | Standard in the common sizes: buy it off the shelf, or have it made to order from 1 piece. |
| A tee with ports in two or three standards — G run, NPT branch, metric gauge port | No | Machined from square or hex bar, each port cut to its own standard, from 1 piece. |
| A two-step reducing tee, or a reducing MFF / FMM tee | No | Machined; the branch single-pointed or tapped to size. |
| An MMM tee, an FFM tee, or any combination the series skips | No | Machined. |
| A cross with mixed ports, or a cross in 316L | No | Machined from square bar. |
| A tee with centre-to-end lengths, a hex position or a bore chosen for the space | No | Machined to the drawing; ports standard. |
| A tee in 316L above 1/2 in, titanium, PEEK or aluminium 6061 / 7075 | No | Same geometry, your material; aluminium for air and vacuum lines only. |
Materials
| Material | Designation | Where it fits here |
|---|---|---|
| Brass | CW614N (CuZn39Pb3) / C36000 machined; CW617N forged forms | standard brass tees and machined tees for air, water and oil |
| Stainless 304 | 1.4301 | standard stainless tees 1/8–1 in |
| Stainless 316L | 1.4404 | machined tees for marine, chemical and washdown lines |
| Free-machining stainless | 303 / 1.4305 | custom turned and milled tees where corrosion duty allows |
| Forged and zinc steel | S235; A105 | hydraulic and structural tees |
| Malleable iron | EN-GJMB / EN-GJMW | standard pipe tees above 1 in |
| Aluminium 6061 | AlMg1SiCu | light pneumatic and vacuum tees |
| Aluminium 7075 | AlZn5.5MgCu | machined manifold blocks with several ports |
Related pages
- fitting types chart — every fitting form by ports and standard
- threaded elbows — two-port corners
- pump fittings — the whole outlet chain
- Pressure gauge adapters — the gauge on the branch
- push-to-connect tube fittings — push-in tees for tube
- quick-screw and cutting-ring fittings — compression tees
- Liquid cooling fittings and manifolds — when the tee becomes a manifold
- fitting thread identification chart — G, R, NPT and metric by diameter and pitch
Frequently asked questions
One male port and two female ports, written in port order: run end, run end, branch. An MFF tee screws its male run end into a pump, valve or manifold port and offers two female ports for the line and a gauge or second line. FMM is the reverse: one female, two male.
Usually an MFF tee: male into the pump outlet, female onward to the regulator or line, and a smaller female branch for a pressure gauge. When the pump is G and the gauge is NPT, or the branch is a size the series skips, the tee is machined with each port to its own standard.
Not as standard parts, where all three ports share one standard and, apart from a one-step reducing branch, one size. A tee with a G run, an NPT branch and a metric gauge port is machined from bar with each port cut separately, from 1 piece.
A tee whose branch, or one run end, is smaller than the others: G1/2 × G1/2 × G1/4 for a gauge, for example. Catalogue reducing tees cover one-step reductions in one standard; two-step reductions and mixed standards are machined.
EKINSUN LTD is a custom parts manufacturer that machines FFF, MFF, FMM, MMM, reducing and gauge tees and crosses with ports in G, R, NPT, metric or UNF threads, in brass, 304 / 316L stainless, steel, aluminium and PEEK, from 1 piece, with a quote within 12 hours.
No list price; the drivers are material, three thread operations, the milling of the body, and quantity. A brass MFF tee with a mixed branch is a short milling and tapping job; a 316L cross with four standards is priced as the machined block it is. The quote states which.
Send the three ports in order
Run end, run end, branch: male or female, standard, size, pitch; centre-to-end lengths if they matter; material; quantity. A photo of the pump or valve port works. 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.