Stainless Flareless Bite Type Fittings

A bite-type fitting works on a difference in hardness. Tightening the nut drives a cutting ring down the tapered bore until its edge cuts into the tube wall, raising a collar of material that grips and seals. The ring must be harder than the tube for that to happen cleanly, and with a stainless ring on stainless tube the margin narrows — the bite goes shallower and less predictably than in steel.

That is why pre-assembly matters more here: setting the ring in a hardened tool rather than the fitting body gives a controlled first bite and leaves the cone unmarked. Dimensions follow DIN 2353 and ISO 8434-1. Against the grade's price and lower pressure ceiling, the payoff is a joint made from plain cut tube, no flaring or welding.

Where it's specified

• Metric plant built to DIN — imported machinery arrives with these ports and stays on them
• Stainless tube runs in chemical service — tube and fitting match, so the joint is not the corroding link
• High-pressure circuits on the S series — the heavy series takes thicker wall and a deeper bite
• Field-made and repaired lines — lines can be made up on site without flaring gear

Range and materials. Straights, 45° and 90° elbows, run and branch tees, bulkheads, adjustable stud ends and reducers in 316/316L, in light (L) and heavy (S) series metric tube sizes, converting to NPT, BSPP, JIC 37° and SAE ORB. Nuts and rings ship with the body.

Ordering notes. Cut the tube square, deburr it, and pre-assemble in a setting tool where one is available; confirm a visible collar has been raised ahead of the ring. Lubricate the cone, ring and nut thread — stainless galls on stainless here as everywhere. Wall thickness must suit the series: thin wall collapses instead of cutting, and an L ring on heavy wall will not set.