NA 69 Series Needle Roller Bearings

The widest of the three needle dimension series tabulated here. Width series 6 against the 49's 4 and the 59's 5, still on diameter series 9, so a NA6903 is 17 mm bore, 22 mm across the needle complement and 30 mm outside like its NA4903 and NA5903 partners and differs only in its 23 mm width. A NA6900 is 10 mm bore, 14 mm across the needle complement, 22 mm outside and 22 mm wide, where the NA4900 on the same envelope is 13 mm. The series carries the three slash bores as well, NA69/22, NA69/28 and NA69/32, and stops at NA6919 — 95 mm bore, 130 mm outside, 63 mm wide — because the catalogues stop there; the 49 and 59 series both run on to 140 mm.

Reading the designation. NA6903 is NA, then 6, then 9, then 03. NA is the type — a needle roller bearing with machined rings, complete with its inner ring. The 6 is the width series and the 9 the diameter series, both of them ISO 15's digits, and only the width digit differs from the 49 and the 59: a NA6903, a NA5903 and a NA4903 are all 17 mm bore and 30 mm outside and stand 23, 18 and 13 mm wide. The bore code follows the same ladder as the other two series, including the three bores that are not multiples of five and are written NA69/22, NA69/28 and NA69/32.

Same envelope, same seat, the most axial room of the three. Because d, Fw and D are identical to the 49 and 59 rows, a NA6903 mounts on the same 17 mm shaft in the same 30 mm housing bore as either of them, and the whole difference is the 23 mm it stands. Against the 49 series that difference runs from 9 mm at the 10 mm bore to 28 mm at the 95 mm one — the wider series gain more as the bores grow, so the gap is not a step you can carry in your head. Take the width off the row.

What the extra width buys. A needle complement carries load along the line where its rollers touch the raceway, so the longest complement of the three sits in this ring and it is the one to reach for when the radial section is fixed and the axial room is not. The cost is the same list as every needle roller bearing: a complement tolerates very little shaft deflection, and the ring offers no self-aligning seat. Load rating and limiting speed are catalogue values for the individual part rather than properties the boundary dimension plan fixes, so neither appears here.

Why this series stops at a 95 mm bore. The 49 and the 59 both run to 140 mm; this one ends at NA6919, 95 mm bore, 110 mm across the needle complement, 130 mm outside and 63 mm wide. That is where the published range ends rather than a line this library drew: the catalogues that carry the series at all stop at the same row. A twentieth bore code does appear in one catalogue on its own, without the needle complement diameter and without a chamfer — three cells of five from a single source, which under this library's two-source rule is not enough to publish. So the ladder stops where the agreement stops.

One chamfer value, and it is the 49 series' value. The pages carry a single r s min, which is what ISO 1206 lays out for this type, with the numeric limits from ISO 582. Same envelope, same corner: a NA6903 takes the same 0.3 mm minimum as a NA4903 and a NA5903, and that holds at every bore the three series share. The build compares each shared bore code cell by cell, so the chamfer has to come out identical and the width has to come out different — a row copied wholesale from the 49 series fails the build rather than publishing a NA6903 that is 13 mm wide.

Why no clearance table is printed on these pages. ISO 5753-1 gives needle roller bearings a radial clearance table of their own and these bores fall inside it, so the figure exists — but the catalogue reproductions of it disagree in every clearance group, so none can be confirmed as the standard's own. The table is left out under this library's two-source rule and the ISO 5753-1 page shows both readings instead.

What is beside it. The same envelope is tabulated narrower as the NA 49 series and the NA 59 series, and without its inner ring as the RNA 69 series, which is this table with the inner ring left out and a hardened, ground shaft taking its place as the raceway. The 48 series is a different envelope altogether — diameter series 8, the 61800 outside diameters, opening at a 110 mm bore — so no row on this page has a partner there. What is not in this series is the drawn cup needle roller bearing, which belongs to ISO 3245 rather than ISO 1206.

Every designation in the table below links to its own page with the ISO 1206 boundary dimensions, the bore-code arithmetic, the needle complement diameter and the same-bore comparison against every other series and type.

This series runs from a 10 mm to a 95 mm bore. The sub-library as a whole reaches 300 mm of bore, and the widest single bearing in it is a 6360, 620 mm across, in the 6300 series. This one stops short of it.

d = bore diameter, Fw = needle complement diameter, D = outside diameter, B = width. All of them are ISO 1206 standard values and are the same for every manufacturer. r s min is the minimum single chamfer dimension the plan gives; its matching maximum is in ISO 582, which is why the column says “min” and not an equality. The last column is derived: radial section = (D − d) / 2, the wall thickness you are working with when you size the housing. No load rating and no limiting speed appears here — see the bearings index for why.

Outside diameter × overall size in millimetres, for the 5 smallest bores in this database. The full charts, one per type, are on the bearings index. Reading a row is what a machine designer does when the shaft is already fixed: the bore does not change, the housing bore does. Across the type boundary the last number changes meaning — it is a width above and a height below — so compare within a type, then decide whether the job wants a ball bearing, a tapered roller or a thrust bearing at all. The 4 series whose type has no bore are not rows here: they are indexed by the shaft they run on, and their chart is above.