Cast Nylon 6 Tube

Cast nylon 6 tube - the same family as extruded nylon but made a different way, and the difference matters. Cast nylon is polymerized directly in the mold rather than melted and pushed through a die, which gives higher crystallinity, almost no internal stress, and the ability to make thick-wall sections and large diameters that extrusion cannot reach. It machines more predictably and holds tolerance better because there is no extrusion stress waiting to relax.

Published figures for cast nylon 6: tensile strength around 11,000 to 12,000 psi, flexural modulus about 450,000 psi, Rockwell R around 115 to 120, and a service ceiling near 210F. Specific gravity is 1.15, a shade heavier than extruded nylon 6/6 at 1.14 - the higher crystallinity. Wear resistance and load-bearing capacity are better than extruded, which is the reason it is specified for bearings.

Where it goes: large bushings and journal bearings, wear rings, thick-wall sleeves, rollers and sheaves, gear blanks, and any bearing part big enough that extruded stock is not available in the size.

How tube is specified, because it trips people up. We list bore, outside diameter and wall thickness for every size so you can see all three at once - the trade more often quotes ID plus wall, or OD plus wall, and the two conventions get confused in both directions. Tell us which dimension is the critical one for your part and we will quote to that one.

Same moisture caveat as all nylons, and it is the thing to plan around: it absorbs water from the air and grows as it does, a few thousandths per inch, with strength and stiffness falling as toughness rises. A part machined dry to a tight bore will not stay that size. Condition for moisture before final machining if the tolerance is tight, and read the published dry figures as a best case.

Machining notes: cast nylon is the easiest nylon to machine well - low stress, consistent through the section, and it takes a good finish. Sharp tools, positive rake, generous chip clearance. Avoid strong acids and oxidizing agents, and do not specify it for sustained hot water or steam. Large cast sections can retain a little molding stress at the very center, so rough out and let a big part settle before finishing.