90° Elbows

When To Use A 90° Elbow

A Burnett & Hillman 90° elbow is used in a hydraulic system when a fluid line needs to change direction at a right angle while maintaining a secure, leak-free connection. These elbows are especially valuable in tight or restricted spaces, where hoses or pipes cannot bend sharply without risking kinks, wear, or reduced flow. By providing a solid 90° turn, the elbow ensures that fluid flow remains efficient and controlled, while also reducing stress on hoses and fittings.

Key Features & Benefits

  • Creates a 90° turn in hydraulic lines for easier routing.
  • Prevents hose kinks and strain, helping extend hose life.
  • Compact design for tight spaces and easy installation.
  • Made from durable, corrosion-resistant steel.
  • High-pressure rated for demanding hydraulic applications.
  • Suitable for a wide range of thread standards and sizes (BSP, NPT, JIC, Metric, etc.).
  • Provides a reliable, leak-free seal when used with the correct washers, O-rings, or sealant.
  • A space-saving and cost-effective solution for routing hydraulic lines efficiently.

Effects On Pressure

  • Pressure Drop: A 90° elbow creates more resistance than a straight fitting, causing a small pressure drop.
  • Use a swept 90° elbow (longer radius) where possible, as it improves flow compared to a tight, compact elbow.
  • Only use elbows where necessary - straight adaptors are always the most efficient.
  • Ensure the elbow is correctly rated for system pressure and flow.

A 90° elbow may slightly reduce flow and increase pressure drop, but in most systems this impact is small, and the benefits of preventing hose damage or improving routing usually outweigh the drawbacks. If you are worried about a reduction in pressure, using a swept 90° elbow such as the Burnett & Hillman ones we provide will lessen the impact on the flow as it has a longer radius.

Connecting Threads Guide

Threads That Match Directly:

  • BSPP to BSPP → Seals with a bonded washer or O-ring.
  • BSPT to BSPT → Seals on the threads with PTFE tape or sealant.
  • NPT to NPT → Seals on the threads with PTFE tape or sealant.
  • JIC to JIC → Seals metal-to-metal on the 37° cone seat.
  • ORFS to ORFS → Seals on the O-ring face for a leak-free joint.
  • SAE O-Ring Boss to SAE O-Ring Boss → Seals with an O-ring at the port face.
  • Metric to Metric → Seals with an O-ring or bonded washer.

Sometimes Compatible (with care):

  • BSPT male into BSPP female → Will screw in, but must be sealed with a washer or sealant.
  • JIC and SAE 37° → Often compatible, both use a 37° flare, but check standards before use.
  • JIS BSPP to BSPP → Same thread, but JIS often seals on a 30° cone rather than a washer.

Not Compatible:

  • BSP ↔ NPT → Different angles (55° vs 60°), will not seal reliably.
  • Metric ↔ BSP/NPT → Different thread form, not interchangeable.
  • UNF ↔ BSP/NPT/Metric → Won’t seal unless part of a designed fitting.
  • NPSM ↔ anything else → Only seals with a gasket, not designed for high pressure.

Rule of thumb:

  • Tapered threads (BSPT, NPT) seal on the thread + tape/sealant.
  • Parallel threads (BSPP, Metric, SAE, UNF) need a washer or O-ring.
  • JIC and ORFS seal on the face or cone, not the thread.

 

BSPP

(British Standard Pipe Parallel) 

BSPT

(British Standard Pipe Tapered)

NPT

(National Pipe Taper)

JIC

(Joint Industry Council)

JIS

(Japanese Industrial Standard)

Metric

(mm)

Imperial (")

(UN/UNF/UNC)

SAE

(Society Of Automotive Engineers)

ORFS

(O-Ring Face Seal)

UNF

(Unified Fine Thread)

NPSM

(National Pipe Straight Mechanical)

Thread Form Parallel Tapered Tapered Parallel with 37° Cone BSPP/Metric (Parallel) Parallel Parallel Parallel (UN/UNF) Parallel (UNF) Parallel Parallel
Flank Angle 55° 55° 60° 60° 55°(BSPP) / 60° (Metric) 60° 60° 60° 60° 60° 60°
Sealing Method Washer / O-Ring Thread Interference + PTFE Tape Thread Interference + PTFE Tape 37° Cone Seat (Metal To Metal) Gasket Or 30°/60° Cone Seat Washer / O-Ring Gasket / O-Ring O-Ring Boss O-Ring On The Face Angled Cone Seat / O-Ring Gasket
Standard ISO 228 / BS 2779 ISO 7 / BS 21 ANSI B1.20.1 (USA) SAE J514 (USA) JIS B 0203 / B 2351 ISO 261 / ISO 724 ANSI B1.1 (USA) SAE J1926 SAE J1453 ANSI B1.1 (USA) ANSI B1.20.1 (USA)
Applications  Medium-high pressure hydraulics, pneumatics, water systems; common in UK/European machinery High-pressure pipework (hydraulic, steam, gas, water); widely used in construction High-pressure hydraulics; common in North American equipment  High-pressure hydraulics (up to ~420 bar); mobile plant, aerospace & automotive Medium pressure hydraulics & pneumatics; Japanese/Asian machinery & vehicles Medium-high pressure hydraulics; European industrial, agricultural & mobile equipment

Low Pressure,  for fastening & mechanical joints, not fluid sealing; general engineering & hydraulic systems

High-pressure hydraulics; common in hydraulic blocks, automotive & aerospace Very high pressure, leak-free hydraulics; common in agriculture, construction, heavy plant Medium pressure hydraulics; also used in automotive, aerospace & precision machinery Low-pressure mechanical joints; used in piping, fire protection & water systems

IMPORTANT: The technical data given on this website is for preliminary information purposes only and is published without guarantee. All line drawings are for illustrative purposes only and should not be regarded as wholly accurate in every detail. We reserve the right to withdraw or to alter the specification of any product without notice. For more information, please consult our Terms of Business.

If you require any further information, our excellent customer service team is here to help so please call us on 01794 835835.

 

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