61900 Series Deep Groove Ball Bearings

One step up from the ultra-thin 61800 series, and still much thinner than a 6000. It buys back ring section — and with it real radial capacity — for a modest increase in outside diameter, which is why it is the usual answer when a 618 is too weak and a 6000 will not fit.

The 61900 series sits one step in from the ultra-thin 61800 series, and that step is worth understanding because it is the one people actually weigh. At a 25 mm bore a 61905 is 42 mm across and 9 mm wide; the 61805 is 37 × 7 and the 6005 is 47 × 12. So the 61900 gives up 5 mm of outside diameter to the 61800 and takes 5 mm off the 6000 — and the ring section it gains over the 61800 is what turns a bearing that merely locates a shaft back into one that can carry a load.

That is the whole argument for the series. Where a 61800 is chosen by space and accepts a low rating, and a 6000 is chosen as the default with capacity to spare, the 61900 is chosen when the housing is tight but the bearing still has to do work: small gearmotors, pumps, fans — the everyday case of a shaft that is thin because the machine is small, turning in a housing that is tight because the machine is small too.

The series runs from 61900 (10 mm bore, 22 mm outside diameter, 6 mm wide) to 61920 (100 mm bore, 140 mm outside diameter, 20 mm wide) in the 21 designations tabulated here. The progression is regular: the radial section grows from 6 mm at the 10 mm bore to 20 mm at the 100 mm bore, staying narrower than the equivalent 6000 at every bore in between.

Every designation in the table below links to its own page with the ISO 15 dimensions, the bore-code arithmetic, the ISO 5753-1 clearance ranges for its bore, and the same-bore comparison against every other series.

This series runs from a 10 mm to a 100 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, D = outside diameter, B = width. All of them are ISO 15 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 6 series whose type has no bore are not rows here: they are indexed by the shaft they run on, and their chart is above.