Enter a bush with or without its bore or a shaft, or pick the size from the list. If the size on the bush has worn off, enter the large end and the length you measured in the fields below: the reader finds the size. Below, an offered bush can be checked against the result.
On the designation alone: the material, the keyway and the condition are checked separately.
Taper bushes hold V-belt pulleys, sprockets and coupling halves on the shafts of pumps, fans and compressors all over a ship, and a bush is named by a four-digit size and its bore. Enter a bush (2012-30, TB 2517-40, 2012-1 1/4) or a shaft (shaft 30 mm), pick the size from the list or enter the large end and the length you measured: the reader says what the digits mean and which bores the size takes in millimetres and inches, gives the large-end diameter and the length, the number and size of the screws and the hex key, says what keyway the bore has, draws the bush, checks an offered bush and writes an RFQ line.
Catalogues also list these bushes as taper lock bushes; Taper Lock and Taper-Lock are trade marks of their respective owners, named here only to identify the size system. QD bushings, flanged bushes and sizes above 5050 (6050, 7060, 8065, 10085) are not in this reader. Screw tightening torques and transmitted torques are not given here.
The outside of the bush is a taper of 8°, as two makers give it; one of them calls it the included angle. The hub of the pulley or sprocket is bored with the same taper for one bush size; as the screws are tightened, the split bush is drawn into the hub and grips the shaft.
The bush is split along its length, so it closes on the shaft. A finished bore has a keyway: metric bores to DIN 6885-1, inch bores on European bushes to BS 46. At the largest bores of some sizes the keyway is shallow and takes a flat key.
The screw holes are half in the hub and half in the bush. The screws draw the bush into the hub; turned into the push-out holes, they press it out again. Up to 3030 two grub screws, from 3525 three cap screws; BSW threads on European bushes, UNC on American ones.
| Size | Large end, mm | Length, in (mm) | Bore, mm | Bore, in | Screws | Hex key, mm |
|---|---|---|---|---|---|---|
| 1008 | 35 | 7/8 (22.2) | up to 25 | up to 1 | 2, 1/4 x 1/2 | 3 |
| 1108 | 38 | 7/8 (22.2) | up to 28 | up to 1 1/8 (more in one table) | 2, 1/4 x 1/2 | 3 |
| 1210 | 47.5 | 1 (25.4) | up to 32 | 1/2 to 1 1/4 | 2, 3/8 x 5/8 | 5 |
| 1215 | 47.5 | 1 1/2 (38.1) | up to 32 | up to 1 1/8 (more in one table) | 2, 3/8 x 5/8 | — |
| 1310 | 50.8 | 1 (25.4) | 14 to 35 | 1/2 to 1 3/8 | 2, 3/8 x 5/8 | — |
| 1610 | 57 | 1 (25.4) | up to 42 | 1/2 to 1 5/8 | 2, 3/8 x 5/8 | 5 |
| 1615 | 57 | 1 1/2 (38.1) | 14 to 42 | 1/2 to 1 5/8 | 2, 3/8 x 5/8 | 5 |
| 2012 | 70 | 1 1/4 (31.8) | 14 to 50 | up to 2 | 2, 7/16 x 7/8 | — |
| 2017 | — | — | — | — | 2, 7/16 x 7/8 | — |
| 2517 | 85.5 | 1 3/4 (44.5) | 16 to 60 (65 in two tables) | up to 2 1/2 | 2, 1/2 x 1 | 6 |
| 2525 | 85.5 | — | — | 3/4 to 2 1/2 | 2, 1/2 x 1 | — |
| 3020 | 108 | 2 (50.8) | up to 75 | up to 3 | 2, 5/8 x 1 1/4 | 8 |
| 3030 | 108 | 3 (76.2) | 35 to 75 | up to 3 | 2, 5/8 | 8 |
| 3525 | 127 | — | 35 to 90 (more in one table) | up to 3 1/2 (more in one table) | 3, 1/2 x 1 1/2 | 10 |
| 3535 | 127 | 3 1/2 (88.9) | 35 to 90 | up to 3 1/2 | 3, 1/2 x 1 1/2 | 10 |
| 4030 | 146 | 3 (76.2) | — | — | 3, 5/8 | 12 |
| 4040 | 146 | 4 (101.6) | 40 to 100 | up to 4 | 3, 5/8 x 1 3/4 | 12 |
| 4535 | — | 3 1/2 (88.9) | — | — | — | 14 |
| 4545 | 162 | 4 1/2 (114.3) | up to 110 | up to 4 1/2 | 3, 3/4 x 2 | 14 |
| 5040 | — | 4 (101.6) | — | — | 3, 7/8 x 2 1/4 | 14 |
| 5050 | 177.5 | 5 (127) | up to 125 | up to 5 | 3, 7/8 x 2 1/4 | 14 |
A value is given only where at least two independent tables give it; values the tables do not agree on are left out. The metric tables round the diameter and the length differently, by up to 1 mm; the length is given in inches, as the inch tables give it. Where some tables bore a size larger than the others, the cell gives the bore every table reaches and, in brackets, the larger bore of two tables (2517) or a note that one table goes further. The smallest bore differs by maker and is given only where the tables agree. Left out: the diameter and length of 2017, the length of 2525 and 3525 (63.5 or 65 mm), the diameter of 4535 and 5040, the metric bores of 2017, 2525, 4030, 4535 and 5040 and the inch bores of 2017, 4030, 4535 and 5040 (one table), the screw length of 3030 and 4030 and the screw size of 4535 (the tables differ), and the hex key of 1215, 1310, 2012, 2017 and 2525.
The values come from published taper bush tables of makers and distributors, European ones with BSW screws and American ones with UNC, and are given only where at least two independent tables agree. The hex keys are checked against two screw tables, the shallow keyways against a key table and a bore table that gives the keyway depth, and the meaning of the four digits against two descriptions of the designation.
It is the size of the bush. Two tables explain the number like this: the first two digits give the largest bore and the last two the length, both in tenths of an inch, so a 2012 takes bores up to about 2.0 in and is about 1.2 in long. The dimension tables give 2 in and 1 1/4 in (31.8 mm). The bore follows the size: 2012-30 is a 2012 bush bored 30 mm, 2012-1 1/4 one bored 1 1/4 in.
No. The pulley, sprocket or coupling hub is bored with the taper of one bush size, and only that size fits it. Sizes such as 1610 and 1615 share the large-end diameter but not the length, so they do not take each other's place either. Read the size off the old bush or the hub, then choose the bore for the shaft.
Two grub screws up to size 3030 and three cap screws from 3525; turned into the other holes, the same screws push the bush out. On bushes made in Europe the screws are BSW (Whitworth), on American ones UNC: the threads do not mix, so keep the screws that came with the bush. A 2012 takes two 7/16 x 7/8 in screws.
A finished bore comes with one. Metric bores are keyed to DIN 6885-1 in three tables; British tables cite BS 4235-1. Inch bores on European bushes are keyed to BS 46. At the largest bores of some sizes the keyway is shallow and takes a flat key: two tables show this for 1008-24, 1108-28, 1610-42 and 1615-42. The key for a metric bore is in the parallel key finder.
The size, the bore with its unit, the keyway and the quantity: Taper bush 2012 with a 30 mm bore and a keyway to DIN 6885. If the size on the old bush has worn off, read it off the hub, or measure the large-end diameter and the length of the bush and the shaft, and attach a photograph.
A row of the tables is a cross-check of sizes, not a part selection. Attach the photograph and your measurements, and Vessel Core checks them before an offer goes back.
