Browning Q-D Bushing Sizes

A Q-D bushing is a tapered, flanged bushing that clamps a sheave, sprocket or pulley onto a shaft. Browning builds the system in twelve series, from the JA 1/2 at the small end to the P series at the large end, covering a 1/2 inch to 7 inch bore range and a 24 mm to 100 mm metric bore range. The series letter is the first part of the bushing number and the bore is the second, so an E 2 is an E series bushing bored 2 inches. This guide gives the bore range of every series, the stock metric bores, how the bushing mounts, and how to read the bushing out of a sheave part number. The full range is in the Q-D bushings category, alongside the Split Taper bushings in the same bushings section.

What are the standard sizes of Browning Q-D bushings?

There are twelve standard series: JA, SH, SDS, SD, SK, SF, E, F, J, M, N and P. Each one covers its own bore range, and the ranges overlap, so more than one series can take the same shaft — the choice is made by the hub the bushing has to fit and by the torque the drive has to carry. Across the whole set the inch bore range runs from 1/2 inch to 7 inches.

The four small series sit close together and are separated by what they will carry rather than by the bore: an SH 1 1/8 and an SDS 1 1/2 carry 3,500 and 5,000 inch-pounds respectively, and the SD is the longer-barrelled version of the SDS on the same cap screw circle. Step up through the SK 1 1/2 and the SF 2 7/16 and the torque capacity goes 7,000 then 11,000 inch-pounds. The rest of the range is numbered the same way, series letter then bore: an SD 1 1/2, an F 2 1/2, a J 3, an M 3, an N 3 and a P 4. Every series but JA carries a set screw over the keyway.

Which Q-D bushing bores do we stock?

The bores below are the ones we hold, series by series, and every one of them is a link to that bushing's product page. Take the series from the sheave and the bore from the shaft, then open the part from its row. Inch and millimeter bores are listed together and climb by shaft size, so a 38 mm bore sits between 1 7/16 and 1 1/2 inches. Where a second fraction follows the bore — 1 3/8 5/16 — the first figure is the bore and the second is the keyway it is cut for.

The list states the bores we hold now, not every bore a series covers — the published range for each series is in the table further up. A bore given in millimeters is bored to that metric size rather than to the nearest inch.

How does a Q-D bushing mount on the shaft?

The bushing is drawn into the tapered bore of the sheave hub by cap screws, and the taper squeezes the split barrel onto the shaft. Align the tapped holes in the bushing flange with the drilled holes in the sheave hub, insert the cap screws through the hub and thread them loosely into the flange, then position the assembly on the shaft and tighten the cap screws progressively and uniformly. Torque them to the wrench figure for the series in the table above.

Removal reverses the same screws. Take the cap screws out, thread them into the tapped holes in the sheave hub, and tighten progressively until the bushing is free of the sheave taper; the assembly then comes off the shaft. The cap screws are always accessible from the outside, whichever way round the bushing is fitted.

Can a Q-D bushing be mounted in reverse?

Yes. A Q-D bushing mounts either way: flange toward the machine or motor, or flange away from it. Both orientations are standard, and the bushing, the sheave and the cap screws are the same parts in each.

The two orientations differ only in which part holds the threads. With the flange toward the machine, the cap screws pass through the drilled holes in the sheave hub into the tapped holes in the flange. With the flange away from the machine, align the drilled holes in the bushing flange with the tapped holes in the sheave hub and pass the cap screws the other way. In both cases the screws go in loosely first, the assembly is positioned on the shaft, and the screws are then tightened progressively and uniformly. To release a bushing mounted flange-away, thread the cap screws into the tapped holes in the flange instead of the hub.

What metric bores are stocked in Q-D bushings?

Stock metric bores run from 24 mm to 100 mm. Each bore is stocked in several series, with the keyseat set by the bore rather than by the series, and the larger bores narrow to the F and J bushings.

Inch bores are stocked in 1/16 inch steps through most of the range. A bushing listed with a shallow keyseat is supplied with a rectangular key cut to fit a standard keyseat in the shaft, and at 1 5/16 and 1 3/8 inches a 5/16 by 5/32 keyway is supplied unless the 3/8 by 3/16 keyway is asked for on the order.

How does a sheave part number say which Q-D bushing it takes?

On a Q-D sheave the bushing series is the letter suffix at the end of the part number. A 1B34SH is a one-groove B sheave that takes an SH bushing, a 1B46SDS takes an SDS, a 2B200SF takes an SF and a 3B380E takes an E, so the suffix tells you the bore range available before you look anything up.

The sheave itself is sold without the bushing, which is what makes one sheave fit a whole range of shafts: pick the V-belt sheave for the ratio and the belt section, then the bushing for the shaft. The same sheave body is also built for the Browning Split Taper system, where the bushing appears in brackets after the part number instead of as a letter suffix; the Split Taper bushing guide covers that range. Shaft diameters stated as a bore code rather than in inches are decoded in the shaft size conversion chart.

Which Q-D bushing fits my sheave and shaft?

Two things have to agree: the bushing series must match the one the sheave hub is bored for, and the bore must match the shaft. The series comes from the sheave part number and the bore from the shaft diameter. The product page states the bore, the keyseat, the cap screw size and the wrench torque the manufacturer publishes for that part.

Reading it off a part you already have

A Q-D bushing is numbered by the series letter and the bore, in the same form used throughout this guide. If the number is unreadable, measure the shaft for the bore and count the cap screws — three on the JA through J series, four on M, N and P — then match the cap screw size against the table above. Send the sheave number and the shaft diameter through the technical support form if that does not settle it and we will confirm the series before you order.