A 45 mm shaft falls in the 44–50 mm range for a 14 × 9 mm parallel key, with 5.5 mm shaft keyseat depth and 3.8 mm hub keyway depth [S2][S4].
The selected 14 mm width, 9 mm height and two mating groove depths control key seating, radial engagement and torque transfer in a keyed hub connection [S2][S5].
14 × 9 mm Dimensions at a 45 mm Shaft Diameter
A 45 mm shaft is within the 44–50 mm nominal diameter range assigned a 14 × 9 mm parallel key. The standard shaft keyseat depth is 5.5 mm, while the corresponding hub keyway depth is 3.8 mm [S2][S4].
The dimensions resolve as follows: 5.5 mm shaft depth plus 3.8 mm hub depth equals the 9 mm key height. The remaining 0.3 mm accommodates the specified dimensional clearance represented by the depth limits, with Hallite listing shaft depth limits of 5.5–5.7 mm and hub depth limits of 3.8–4.0 mm [S2].
For procurement and inspection, state all four values on the drawing: shaft diameter 45 mm, key section 14 × 9 mm, shaft keyseat depth 5.5 mm and hub keyway depth 3.8 mm. The shaft key itself should be specified by width, height and required length, not by shaft diameter alone.
Compare Shaft and Hub Depth Requirements
The 14 × 9 mm key is the common 44–50 mm size in the DIN 6885 and ISO 773 dimensional arrangement, while the published coupling table gives the 5.5 mm shaft depth and 3.8 mm hub depth for that same size [S4][S5].
For a coupling bore, Rexnord lists the 14 mm keyway width with a tolerance of −0.0215/+0.0215 mm, hub depth limits of 3.8–4.0 mm and a keyway radius of 0.25–0.40 mm [S5]. These limits are product-table requirements and should be checked against the purchased coupling drawing rather than assumed to apply to every 45 mm hub.
How the Key Seats in a 45 mm Hub
The 9 mm key height is divided between the 5.5 mm shaft keyseat and the 3.8 mm hub keyway, leaving 0.3 mm for clearance. This arrangement positions the key partly in the shaft and partly in the hub while leaving the 14 mm side faces available for tangential force transmission [S2][S4].
The practical selection rule is that hub keyway depth is approximately half the key height plus a small clearance allowance. For the 9 mm key height, the selected 3.8 mm depth is close to the half-height value of 4.5 mm, with the difference allowing for the shaft keyseat and assembly clearance [S4].
Do not deepen the hub groove merely to compensate for a shaft keyseat made too shallow. That practice reduces the key engagement available in the hub and shifts the fit toward a shaft-side condition. The shaft collar or other axial retention feature is a separate design decision and does not change the 14 × 9 mm groove geometry.
Fit, Tolerance and Inspection Decisions
Hallite gives the 14 × 9 mm BS 4235 key width as 13.979–14.021 mm and the corresponding hub keyway width as 13.957–14.000 mm. Its shaft depth limits are 5.5–5.7 mm, while its hub depth limits are 3.8–4.0 mm [S2].
The listed keyway corner radius for the 14 × 9 mm BS 4235 size is 0.40 mm [S2]. Rexnord’s coupling dimensions instead list a 0.25–0.40 mm radius for the 14 mm coupling keyway, reflecting a different product envelope and fit arrangement [S5].
For inspection, record the shaft diameter, key width, key height, shaft keyseat depth, hub keyway depth and groove radius on the component inspection sheet. ISO/R 773 Js9 width tolerance is used for metric keys and keyways in the cited coupling table, with DIN 6885/1 compliance stated; however, the purchase specification and the component drawing remain the controlling documents [S5].
Where This Key-and-Keyway Arrangement Fits
This geometry is suitable for a conventional parallel-keyed shaft and hub connection using a 14 × 9 mm key, including the 44–50 mm shaft range identified in DIN 6885/1 and ISO 773-based tables [S4][S5]. It is not a 14 mm square key, because the standard key height is 9 mm rather than 14 mm [S2].
A 45 mm shaft paired with a 38–44 mm-size 12 × 8 mm key is undersized for the nominal shaft range, while a 50–58 mm-size 16 × 10 mm key is oversized. The difference is not cosmetic: the 12 × 8 mm size has 3.3 mm nominal shaft depth and 3.3 mm hub depth, while the 16 × 10 mm size has 6.0 mm shaft depth and 4.3 mm hub depth [S2].
The arrangement is intended for a keyed hub, not a design that relies on key friction as a substitute for a defined torque capacity. For applications where axial retention also matters, compare the keyed interface with a locking assembly rather than adding an unrelated retaining feature that changes the groove geometry.
Standards and Machining Documentation
DIN 6885 relates the shaft diameter to the key section for normal applications, while IS 2048 defines parallel-key and keyway dimensions, tolerances and key types. IS 2048 identifies a 50 mm-long, 12 × 8 mm Type A key as “Parallel Key A 12 x 8 x 50,” demonstrating that designation format should state type, width, height and length [S3][S8].
For this 45 mm shaft, the metric section remains 14 × 9 mm, but the required key length must come from the connection geometry. IS 2048 distinguishes keys with round ends, square ends, retaining-screw holes, jacking-screw provisions and other configurations, so a drawing must identify the required key type rather than order a generic blank [S3].
Any production drawing should therefore call out the 45 mm shaft, 14 × 9 mm key, 5.5 mm shaft keyseat depth, 3.8 mm hub keyway depth, applicable tolerances and groove radius. The traceable check is to measure the finished shaft and bore after machining, then confirm that the assembled key meets the stated width and depth limits [S2][S5].
The next trackable check is straightforward: verify the assembled key projection, groove widths and shaft-to-hub fit against the drawing, using the 14.000 mm nominal key width, 5.5–5.7 mm shaft depth range and 3.8–4.0 mm hub depth range as inspection limits [S2].