What the Push-In Elbow Does
This push-in elbow is the tool-free half of a two-page elbow pair. The tube enters the fitting and is held by a grab ring, while an NBR seal closes against the tube outside diameter. No wrench is needed at the tube port. The mating port is threaded, and the body is available as a fixed or swivel (rotating) style. The swivel version lets you orient the run without re-bending the tube. Where a wrench-tightened compression joint is preferred by site practice, see the threaded brass elbow, which is covered on its own page.
Declared Specifications
| Body material | nickel-plated brass |
| Seals | NBR |
| Release ring | POM |
| Tube sizes | outside diameter 4, 6, 8, 10, 12 mm and 1/4 inch |
| Threads | M6, M8, M10x1, R1/8, R1/4 (BSPT form), NPT, UNF |
| Standard version working pressure | 30 to 60 bar |
| High-pressure version | up to 250 bar |
| Temperature | -20 to +70 °C, some sizes to +80 °C |
| Insertion depth | 15 mm for 4 mm tube, 17 mm for 6 mm tube |
| Body styles | fixed or swivel (rotating) |
Preparing and Inserting the Tube
Tube condition decides whether the joint holds. Cut the tube square with a proper tube cutter, not side cutters. After cutting, check the end: no burrs, no oval bore, no score marks along the sealing zone.
Push the tube into the fitting until it stops. Insertion depth is 15 mm for a 4 mm tube and 17 mm for a 6 mm tube. Then give a slight pull-back check: pull gently and the grab ring should hold with no movement at the seal. If the tube slides back, it was not fully inserted, so withdraw it and repeat.
Reuse and Service
Depressurise the line before any work. Press the release ring squarely with a finger or a small flat tool, then withdraw the tube. The POM release ring pushes the grab ring clear, so no force on the tube is needed. Never pull a pressurised joint apart.
On re-insertion, the old grab-ring marks will sit in the seal zone. Cut off the marked section with a tube cutter and re-insert fresh tube. The body itself can be reused when the seal and grab ring are sound. Inspect the seal for cuts, hardening or embedded grit, and check the grab ring teeth for damage. If either part is suspect, replace the fitting. Do not re-insert a tube over grab-ring marks and expect a quiet joint; that is how weeping starts. For additional push-to-connect grease line fittings and matching components, review the range before planning a rebuild.
Pressure and Temperature Limits
The standard version works from 30 to 60 bar and covers normal oil mist and return lines. The high-pressure version reaches up to 250 bar, but that figure is conditional on the tube: material, wall and grade of PA or PE tubing all set the real limit. Temperature acts on the same tube, so confirm tube and temperature together when ordering. Temperature range is -20 to +70 °C, with some sizes to +80 °C.
Thread forms available are M6, M8, M10x1, R1/8, R1/4 in BSPT form, plus NPT and UNF. Match the port form exactly; forcing a mismatched thread damages the body. For a quotation on a specific size, contact the team with the tube size, thread and medium.
Keeping Lines Reliable
Never let the elbow carry bending load. Leave a straight run of tube after the fitting, then clip the line so vibration and machine movement stop at the clip. A bending moment fed into the grab ring works the seal and shortens service life.
NBR seals suit mineral oils generally. For lubricants with aggressive additives or for synthetic media, confirm compatibility before assembly, because a swollen seal will weep. Swivel bodies help orientation without re-bending the tube, which keeps the seal zone straight and undisturbed. Choose a threaded elbow instead for permanent installations, for higher cyclic loads, or where a wrench-tightened joint is the preferred site practice. Review the full lubrication fittings range when specifying a complete line.
Frequently Asked Questions
Is the 6 mm size the tube outside diameter?
Yes, all listed sizes are tube outside diameter, including 4, 6, 8, 10 and 12 mm.
Can the high-pressure version reach 250 bar with any tube?
No. The limit depends on tube material, wall and temperature; contact the team to confirm.
Can fittings be reused after a tube change?
Yes, if the seal and grab ring are sound. Cut off the marked tube section first.
How deep should the tube be inserted?
Push until it stops: 15 mm for a 4 mm tube and 17 mm for a 6 mm tube.
How is a tube released?
Depressurise, press the release ring squarely, then withdraw the tube by hand.
Are inch tube sizes available?
Yes, 1/4 inch tube outside diameter is listed alongside the metric sizes.
How do I avoid side loads on the fitting?
Leave a straight tube run after the fitting and clip the line close by.
Which media suit the NBR seals?
Mineral oils generally. Confirm compatibility for additive-heavy or synthetic media before assembly.
When should I choose a threaded elbow instead?
For permanent installations, higher cyclic loads, or where site practice prefers a wrench-tightened joint.
How do I get specifications and a quotation?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
