Hydraulic fittings
Crimp hose fittings, DIN 2353 compression tube fittings, swivel, elbow and tee fittings, bulkhead fittings, quick couplings and flange connections; BSP, BSPT, metric and JIC threads.
The most common mistake in hydraulics is not choosing the wrong product but fitting the wrong thread because it looks right: threads look alike to the eye, turn a few times by hand, and then the connection leaks or blows off under pressure. When you send us the old fitting or a photo of it, we measure the thread and find the correct match; in hose assemblies we select the fitting from the same system as the hose and crimp it. We ship fittings and connectors from stock anywhere in Türkiye and abroad, and also sell them through our online store hidroticaret.com (Turkish).
Types
Hose fittings
Fittings crimped onto the hose: straight, 45° and 90° elbow; selected to match the hose type and inside diameter.
Compression tube fittings (DIN 2353)
Seal by tightening a cutting ring on the tube end into a 24° cone seat; light (L) and heavy (S) series.
Swivel fittings
Allow the hose or tube connection to rotate; prevent twisting and make installation easier.
Elbow, tee and cross fittings
Connectors that redirect the line and split it into branches; on adjustable types the orientation is set during installation.
Bulkhead (panel) fittings
Connections that pass through a wall, tank or chassis plate; fixed with their own nut.
Hydraulic quick couplings
Connect and disconnect the line without tools; flat face types do not spill oil or take in dirt when disconnected. Used on agricultural and construction machinery attachments.
Flange connections
Pump and valve connections on large bore, high pressure lines; SAE 3000 and 6000 psi series.
Product images: hidroticaret.com.
How to select
Three things are measured to identify the right fitting: the outside diameter of the thread, the thread pitch and where the seal is made. Parallel thread connections (BSP, metric) do not seal on the thread; the seal is made by an O-ring, a sealing washer or a cone seat. Tapered thread connections (BSPT, NPT) seal on the thread itself and need thread tape or liquid sealant.
BSP and metric are told apart by the thread pitch: BSP pitch is given in threads per inch (1/4" BSP = 19 threads per inch), metric pitch in millimeters (M18x1.5). A thread gauge separates the two with certainty. The BSP size is not the diameter of the thread but the old nominal pipe size; this is why the outside diameter of a 1/4" BSP thread is 13.16 mm, not 6.35 mm. The tables below give the most commonly encountered sizes.
DIN 2353 compression fittings are used on tube lines: the fitting is selected by tube outside diameter and comes in the light (L) or heavy (S) series. For the same tube diameter the L and S series have different threads; the heavy series carries higher pressure. The cutting ring is set onto the tube at first assembly; the correct tightening torque is the condition for a leak-free joint and for the tube not pulling out.
When a fitting leaks, first check whether the thread and the sealing method match, then the condition of the O-ring or cutting ring. Wrapping tape on a parallel thread does not fix the seal; it only makes disassembly harder, and tape fragments get into the system.
BSP (G) thread sizes
| Nominal size | Thread outside diameter (mm) | Threads per inch |
|---|---|---|
| 1/8" | 9.73 | 28 |
| 1/4" | 13.16 | 19 |
| 3/8" | 16.66 | 19 |
| 1/2" | 20.96 | 14 |
| 5/8" | 22.91 | 14 |
| 3/4" | 26.44 | 14 |
| 1" | 33.25 | 11 |
| 1 1/4" | 41.91 | 11 |
| 1 1/2" | 47.80 | 11 |
| 2" | 59.61 | 11 |
BSP parallel (G, ISO 228) and tapered (R, BSPT, ISO 7) threads have the same outside diameter and pitch; the difference is the taper. Measure the outside diameter with a caliper and find the nominal size in the table.
Tube diameter and thread for DIN 2353 compression fittings
| Light series (L): tube Ø | Thread | Heavy series (S): tube Ø | Thread |
|---|---|---|---|
| 6 mm | M12x1.5 | 6 mm | M14x1.5 |
| 8 mm | M14x1.5 | 8 mm | M16x1.5 |
| 10 mm | M16x1.5 | 10 mm | M18x1.5 |
| 12 mm | M18x1.5 | 12 mm | M20x1.5 |
| 15 mm | M22x1.5 | 14 mm | M22x1.5 |
| 18 mm | M26x1.5 | 16 mm | M24x1.5 |
| 22 mm | M30x2 | 20 mm | M30x2 |
| 28 mm | M36x2 | 25 mm | M36x2 |
| 35 mm | M45x2 | 30 mm | M42x2 |
| 42 mm | M52x2 | 38 mm | M52x2 |
DIN 2353 (ISO 8434-1). The fitting is selected by tube outside diameter; the L and S sizes on the same row are not equivalents of each other, the two series are listed separately. The heavy series carries higher pressure.
Frequently asked questions
What is the difference between BSP and BSPT threads?
BSP is a parallel thread, BSPT a tapered thread. BSP seals with a sealing washer or O-ring, BSPT on the thread itself. Because the outside diameter and pitch are the same, they appear to screw together, but they do not seal.
How do I tell whether a thread is metric or BSP?
Measure the pitch with a thread gauge: if a threads-per-inch blade fits it is BSP, if a millimeter pitch blade fits it is metric. Then compare the outside diameter measured with a caliper against the values in the table.
Should I use PTFE tape on a parallel thread?
No. On a parallel thread the seal is made by a sealing washer, an O-ring or a cone seat; tape does not fix a leak and its fragments can get into the system.
Why is the outside diameter of a 1/4" BSP thread not 6.35 mm?
The BSP size is not the diameter of the thread but the old nominal pipe size. The outside diameter of a 1/4" BSP thread is 13.16 mm.
Are JIC and ORFS fittings interchangeable in the same size?
No. JIC seals on a 37° cone seat, ORFS on an O-ring in the flat face; their threads are different as well.
I cannot measure the thread type, what should I send?
Send us the fitting itself or a clear photo of it with a ruler next to it; we measure it and find the match.
Stock, sizes and part numbers
Sizes in stock, manufacturer part numbers and brands are kept up to date in our catalog. Send us your requirement on WhatsApp or by e-mail and we will quote and ship worldwide.