DIN 6887 Gib Head Taper Key

A DIN 6887 gib head taper key is a steel key with a 1:100 taper on its top face and a head on the thick end. It is driven into the keyway after the hub is already on the shaft: the taper wedges the joint tight, and torque is carried by friction on the top and bottom faces. The head is there for removal: the key comes out from the head side, with no access needed to the other side of the assembly.

How the joint works

The shaft keyway has a flat bottom; the hub keyway has the same 1:100 taper as the key. Driving the key in creates radial interference: the hub is pressed onto the shaft and the joint is preloaded. The side faces of the key run with clearance. Unlike a DIN 6885 parallel key, a taper key holds the hub against axial movement as well as rotation.

The downside of that interference is that the hub is pushed off the shaft axis, which causes runout. DIN 6887 keys are therefore used in slow-running assemblies where concentricity is not critical: pulleys, sprockets, couplings, flywheels, conveyor shafts, and agricultural and road machinery. For gear drives and high-speed shafts, parallel keys (DIN 6885) or Woodruff keys (DIN 6888) are the better choice.

Fitting and removal

• The key is fitted to the hub keyway: the tapers must match, or the key will bear on only part of its length.
• Leave a gap between the head and the hub face — a drift is driven into it to remove the key.
• The head projects beyond the hub and turns with the shaft, so it must be covered by a guard: on an open shaft it catches clothing and rags.

DIN 6887 dimensions

The key section is chosen by shaft diameter, and the length by hub length, from the standard series of 14 to 400 mm. Width b tolerance is h9; height h tolerance is h9 or h11 per DIN 6880.

Section b × h, mm	Recommended shaft diameter d, mm	Length l, mm
4 × 4	over 10 to 12	14–45
5 × 5	over 12 to 17	14–56
6 × 6	over 17 to 22	16–70
8 × 7	over 22 to 30	20–90
10 × 8	over 30 to 38	25–110
12 × 8	over 38 to 44	32–140
14 × 9	over 44 to 50	40–160
16 × 10	over 50 to 58	45–180
18 × 11	over 58 to 65	50–200
20 × 12	over 65 to 75	56–220
22 × 14	over 75 to 85	63–250
25 × 14	over 85 to 95	70–280
28 × 16	over 95 to 110	80–320
32 × 18	over 110 to 130	90–360
36 × 20	over 130 to 150	100–400
40 × 22	over 150 to 170	110–400
45 × 25	over 170 to 200	125–400
50 × 28	over 200 to 230	140–400

The standard also covers larger sections, from 56 × 32 to 100 × 50 mm for shafts up to 500 mm, but sets no standard lengths for them: these keys are made to drawing.

Designation example: gib head taper key 10 × 8 × 50 DIN 6887 — width 10 mm, height 8 mm, length 50 mm.

Material and related standards

DIN 6887 keys are usually made from cold-drawn C45+C steel with a tensile strength of at least 600 N/mm².

• DIN 6886 — the same taper key without a head, used where the key can be driven out from the opposite side.
• DIN 6884 — gib head taper key for seating on a flat on the shaft.
• GOST 24068-80 — the Russian standard for taper keys with and without a head. When substituting GOST for DIN, check dimensions against the tables of both standards.

Buy DIN 6887 keys

FLOK supplies DIN 6887 gib head taper keys wholesale. To select a key, send us the shaft diameter and hub length, or a ready specification, and we will prepare a quotation.