ANSI external · DIN 471 external · ANSI internal

Retaining ring groove dimensions

Groove diameter, width, depth and ring thickness by shaft or bore size for the three retaining-ring series the configurator cuts, with the groove tolerances the ANSI rows carry. The same rows the engine applies when you place a ring on a diameter.

A retaining ring is a purchased part; what the shop machines is the groove it snaps into. The ring maker publishes, for each shaft size, the groove diameter, groove width, the depth that follows from the two, and the ring thickness the width must clear. Cut the groove to those numbers and the ring seats and holds; cut it to a general-purpose tolerance and it may stand proud or walk.

Three series are tabled here, named as the engine stores them. ANSI external covers shaft diameters from 1/8″ to 10″ (76 of 95 sizes shown, to 4″; the CSV has all of them). DIN 471 external covers metric shafts from 3 to 200 mm, stored in inches as the configurator applies them (74 of 109 shown, to 100 mm). ANSI internal covers housing bores from 1/4″ to 2″; there the groove cuts outward from the bore wall. External groove depth is (shaft Ø − groove Ø) / 2, measured in from the OD; internal depth is (groove Ø − bore) / 2.

Place a retaining ring on a diameter in the configurator and it emits the groove from the matching row: width and depth, and on the ANSI series the groove-diameter and width tolerances as well, so the drawing carries the ring maker's band rather than the part's default tolerance.

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ANSI external retaining ring grooves, shaft Ø to 4″

Inches. Groove Ø tolerance is ± on the diameter; width tolerance is plus-only. Depth = (shaft Ø − groove Ø) / 2. The CSV carries all 95 sizes to 10″.

Download this table (CSV)

DIN 471 external retaining ring grooves, shaft Ø to 100 mm

Metric shaft sizes; the groove values are stored and applied in inches (converted from the metric table). No tolerance is seeded for this series.

ANSI internal retaining ring grooves (housing bore)

Inches. The groove cuts outward from the bore wall: depth = (groove Ø − bore Ø) / 2.

Catalog parts whose ring groove is a table row

Computed from the part data: listed only where the shaft diameter, groove width and depth all equal the ANSI external row.

The two tolerances, and why width is plus-only

On the ANSI series every row carries a groove-diameter tolerance (95 of 95 external rows, all 19 internal rows) and a groove-width tolerance (90 external rows; the largest shafts have none seeded). The diameter band is symmetric: at 3/4″ it is ±0.003 on a 0.704″ groove diameter, which is half that, ±0.0015″, on the 0.023″ depth the lathe actually cuts. The width band is not symmetric: +0.003 / −0 at the same size. A groove may be wider than nominal (the ring gains axial play) but never narrower, because the ring will not enter.

The DIN 471 rows carry no tolerance in the data (0 of 109); a metric groove loads with its width and depth and the part's own tolerance until that series' table is seeded. The configurator applies what the row holds and nothing it does not.

Catalog parts cut to these grooves

The parts table lists the 14 catalog parts (Gear-Box Plug-In Shafts) whose retaining-ring groove is the ANSI external row for its shaft diameter, width and depth exactly. Other catalog shafts with a ring groove (the idler shafts, for one) take the groove from the OEM or cross-reference catalog they reproduce, so they are not listed against this table.

Related: Gearbox shafts · Idler shafts · Shaft fits and tolerances.

Frequently Asked Questions

These references are for specifying a part; every value here is one the configurator applies when you build one. Numbers are representative of the standard; check them against your part and its mating components before ordering. See all guides on the guides page.