AN Fitting Assembly Tool Guide: Crimping and Installing Hose Ends

Braided AN hose ends push into the fitting with an assembly tool; crimp-style ends need a crimper loaded with the manufacturer’s exact die set.

One wrong detail — a slanted cut, a 45-degree line forced onto a 37-degree seat — turns a finished AN hose assembly into a leak that shows up at the worst moment. Two tool families cover the job, and which one you reach for depends on the style of hose end on your bench.

Braided stainless steel lines go together with a push-on assembly tool that drives the hose into the fitting socket quickly and evenly. Crimped hose ends take a different route: a crimper squeezes the ferrule onto the hose using the die set and crimp setting listed for that exact hose and fitting series. Both routes share the same non-negotiables — a square cut, the correct series, and a final check that the joint is seated, aligned, and crimped to the listed diameter.

How Does A Push-On Assembly Tool Work?

A push-on assembly tool seats braided AN hose inside the fitting socket by letting you twist the hose into a tapered throat until it bottoms out at the fitting’s internal lip.

Work through it in this order:

1. Cut the hose square with a sharp blade or fine-tooth saw, then trim burrs and frayed stainless strands off the end.
2. Clamp the tool in a vise, but only snug it. The plastic body can crack if you overtighten the jaws.
3. Set the fitting socket into the tool with the tapered end facing out.
4. Twist the hose into the tapered end and keep pushing until it stops against the internal lip of the fitting.
5. Pull the assembly free and check that no braid bunched up behind the socket.

When it’s seated, the hose stops dead at the lip and refuses to turn further by hand — that’s your confirmation it went in all the way.

One current tool sold as the AN Hose Assembly Tool – Braided Stainless Steel Lines covers sizes -4 through -16. If you’re still picking a kit, there’s a tested roundup of AN fitting tools that compares what each one handles before you commit.

Crimping And Installing Hose Ends: What The Crimp Chart Decides

Crimped assemblies live or die by the chart: you need the correct ferrule, die set, crimp setting, and finished crimp diameter for your hose and fitting series before the machine ever closes.

1. Pull the ferrule, die, approximate crimp setting, and target crimp diameter from the crimp data chart for your hose series.
2. Load and lubricate the dies as the manufacturer directs, then position them in the machine.
3. Set the fitting’s orientation now. A crimped coupling won’t rotate later, so get the clock angle you want before anything squeezes down.
4. Insert the hose assembly and align it on the die step. Parker’s PHastkrimp instructions use PARKALIGN to rest the coupling on that step correctly.
5. Fit the die ring on top if your machine uses one, then put on safety glasses and keep hands and clothing clear of the moving parts. Parker’s hose assembly and crimping guide spells out the machine sequence.
6. Hold the down button until the die ring contacts the crimper bowl. Press up to retract the ram and release the finished assembly.
7. Measure the crimp diameter against the chart. If it’s outside range, the die or setting was wrong.

Thermoplastic and fluoropolymer hose follows the same logic: match the fitting series to the hose, inspect the threads and through-hole, oil the inside of the hose end with SAE 20 weight lubricating oil where specified, then tap the fitting on until the shell bottom meets the insertion depth mark.

The Mistakes That Ruin An Otherwise Good Assembly

Nearly every leaking AN joint traces back to a bad cut, a mismatched flare, or a crimp that never matched the chart — not to cheap parts.

• Cutting unevenly or leaving burrs and frayed braid on the end.
• Forcing a 45-degree line onto a 37-degree AN/JIC fitting. The seat takes damage and the joint weeps.
• Overtightening the tool in the vise until the body cracks.
• Running the wrong die, ferrule, or crimp setting for the hose series.
• Skipping lubrication where the manufacturer specifies it.
• Tightening the finished fitting with whatever wrench is closest — use the correct size and soft jaws so anodized surfaces stay intact.
• Calling the job done without confirming full seating and alignment first.

Run the whole thing in order: square cut, matching series, 37-degree flare, lubrication where the chart asks for it, seating and alignment, then crimp or push-on to the listed spec. That final measurement is what tells you the assembly will hold instead of weeping at the first pressure test.