V-Belt Sheave Sizes and Browning Sheave Numbers

A Browning sheave number states the number of grooves, the belt section the grooves are cut for, a diameter, and how the sheave mounts to the shaft. Once those four pieces are read, the size tables below give the outside, datum and pitch diameters and the bores each part is stocked in. This guide covers the FHP sheaves in the AK and BK series, the V-belt sheaves in the B5V, TB, TC and Q-D families, the Split Taper bushings and Q-D bushings that bushed sheaves mount on, and the variable pitch range.

How do you read a Browning sheave number?

Read it in four pieces, left to right: a leading digit for the number of grooves where the sheave has more than one, letters for the groove section, digits for a diameter, and a trailing letter or an x-dimension for the bore. A trailing letter is a bushing designation; an x followed by a fraction is a finished bore machined to that size. The digits mean a nominal diameter reference on the AK and BK series, a datum diameter on the classical A, B and C bushed series, and an outside diameter on the narrow-groove and variable pitch series.

Diameters are stated as a datum diameter for the A, B and C sections and as a pitch diameter for the 3L, 5V and 8V sections, so a sheave cut for two sections carries two figures for the same groove.

What is the difference between an AK and a BK sheave?

An AK sheave has one groove cut for a 4L or A section belt, and a 3L belt may also be used in it. A BK sheave has a single combination groove that takes a 4L or A belt and a 5L or B belt, which is why a BK number lists two datum diameters, one for each section. Both are cast iron sheaves and both carry the same keyseat schedule. The AK series is machined from fine grained cast iron, statically balanced, painted and individually packaged, and is furnished with standard keyseats and hollow head setscrews.

Because the two sections ride at different depths, the same physical sheave reads as one diameter for an A belt and a larger one for a B belt. An AK64X1 is the 1 inch finished bore version of the AK64: a 6.25 inch outside diameter with a 1/4 by 1/8 inch keyseat. The keyseat follows the bore rather than the diameter and is omitted at 1/2 inch, 3/16 by 3/32 inch from 5/8 to 7/8 inch, 1/4 by 1/8 inch from 15/16 to 1 1/4 inch, and 3/8 by 3/16 inch at 1 7/16 inch.

The same diameters repeat in two and three groove form. Finished-bore 2AK sizes run 2AK20 through 2AK184 and 2BK sizes 2BK25 through 2BK190, both in bores from 1/2 to 1 7/16 inch; the three groove combination groove is stocked as 3BK and 3BKH.

What does the H at the end of a sheave number mean?

H is a bushing designation, not a diameter: an AK89H is the AK89 sheave bored to take a Browning Split Taper H bushing instead of being machined to one finished bore. The H bushing covers bores from 3/8 to 1 1/2 inch, so one sheave casting serves that whole range and the bore is decided when the bushing is chosen. An AK89H lists exactly that: an 8.75 inch outside diameter, an 8.50 inch datum diameter for an A belt, an 8.16 inch pitch diameter for a 3L belt, and a bushing bore range of 0.375 to 1.500 inch.

A Split Taper bushing is keyed to both the shaft and the sheave hub, so the external key drives the sheave and no torque is carried by the cap screws, and its double split barrel clamps concentrically on the shaft. The taper is 3/4 inch per foot on diameter across the whole line, which runs from 3/8 inch through 7 7/16 inch bores in inch sizes, 10 mm through 95 mm in metric, and 5/8 inch through 1 3/8 inch in spline bores. The bushings that carry the stock A and B section sheaves are the six below; the AKH and BKH series take the H bushing and nothing else.

What belts does a B5V sheave take?

A B5V sheave has one combination groove that accepts 4L, A and AX belts, 5L, B and BX belts, and 5V and 5VX belts, so a single sheave covers the classical B section and the narrow 5V section. The line runs from one through six grooves and up to 125 horsepower, on Split Taper bushings with a 1/2 to 3 3/4 inch bore range. A B5V sheave can be the driver or the driven sheave in a drive that already uses traditional A and B sheaves, and takes the same belts; because B and 5V grooves use different spacing, B5V sheaves are not designed for banded belts.

The digits after B5V are the datum diameter for a B belt in tenths of an inch, so a 1B5V44 is a single groove sheave with a 4.4 inch B datum diameter, a 4.0 inch A datum diameter and a 4.5 inch 5V pitch diameter, on a P1 bushing. The single groove sizes are below. The same diameters are stocked in two, three and four groove form, and all of them except B5V234 and B5V278 in five and six groove form.

What are TB and TC sheaves?

TB and TC are Gripbelt sheaves on Split Taper bushings, separated by the belt section they are cut for. A TB sheave takes all A and B section belts and runs from one to six grooves, 3.75 to 38.35 inch outside diameter, with a 1/2 to 2 11/16 inch bore range. A TC sheave takes all C section belts, also one to six grooves, 7.40 to 24.40 inch outside diameter, with a 1/2 to 2 5/8 inch bore range.

On both, the digits are the datum diameter in tenths of an inch for the section the sheave is named after. A 1TC70 is a single groove C sheave with a 7.0 inch C datum diameter, a 7.40 inch outside diameter and a 1 1/4 inch face width, on a Q1 bushing. Neither TB nor the related B Gripbelt sheave may be used with 5V belts — that is what the B5V combination groove above exists for. Matching V-belts are sized by section and length, which the guide to FHP V-belt sizes sets out.

How do you read a Q-D sheave number?

A Q-D sheave number ends in the Q-D bushing it is bored for, and that suffix is the part of the number that decides the shaft size. A 1B34SH is a single groove B section sheave with a 3.4 inch datum diameter for a B belt, a 3.0 inch datum diameter for an A belt and a 3.75 inch outside diameter, bored for an SH bushing and therefore covering 1/2 to 1 5/8 inch shafts. Change the suffix and the same diameter covers a different shaft range: a 1B46SDS carries an SDS bushing and reaches 2 inches.

On the classical A, B and C section sheaves the digits are the datum diameter in tenths of an inch; on the narrow 3V, 5V and 8V sheaves they are the outside diameter in hundredths, so a 13V220JA is a single groove 3V sheave of 2.20 inch outside diameter on a JA bushing. A Q-D bushing can be reverse mounted, its cap screws are reached from the outside either way round, and every designation except JA has a setscrew over the keyway. Stock bores run 1/2 to 7 inch.

Which sheaves have the same datum diameter?

Six single-groove families reach the same diameters by different mounting methods, so a drive ratio can usually be held while the bore arrangement changes. The table lists, for one datum diameter, the finished-bore AK and BK sheave, the H-bushed AKH and BKH sheave, the B5V sheave, the TB sheave and the Q-D sheave. A dash means no stock sheave in that family lands on that diameter.

An A belt will run in a B sheave, but a B belt will not run in an A sheave, so the A and B columns are not interchangeable in both directions. The AK and BK columns are finished bore and the AKH and BKH columns take the H bushing; the B5V, TB and Q-D columns are bushed, and the bushing decides the shaft size.

What is a variable pitch sheave?

A variable pitch sheave has movable flanges, so its pitch diameter is adjusted in place rather than fixed at manufacture. Turning the threaded collar clockwise moves the angular faced flanges closer together and the belt rides higher in the groove, increasing the pitch diameter; turning it counter clockwise lets the belt ride lower and the diameter falls. The diameter is infinitely adjustable between the minimum and maximum setting, and a locking collar holds the flanges once the setting is reached.

Four families cover the range. VL and VM are single groove sheaves with a 1.6 to 4.7 inch pitch diameter range, for light duty applications up to 5 horsepower. VP is single and double groove, 3.4 to 8.4 inch, for heavier service up to 30 horsepower. MVP is multiple groove, up to five grooves and a 3.4 to 17.2 inch range, for multiple belt drives up to 230 horsepower, and every MVP sheave is dynamically balanced. A 1VP50X1 is a single groove VP with a 1 inch finished bore and a 4.75 inch outside diameter, cut for 3L, 4L or A and 5L or B belts. VL, VM and VP sheaves are available in finished bore, and the bushed and MVP versions take Split Taper or Q-D bushings.

To find a replacement, read the number off the sheave and match the diameter and bore in the tables above, then filter the V-belt sheaves or FHP sheaves category by groove count and bore. If the number is worn off, measure the outside diameter, the groove count and the shaft, and send those three figures through the technical support form and we will confirm the sheave and the bushing before you order.

Which AK, BK and variable pitch sheave numbers do we stock?

AK64 and BK50 are sizes rather than whole part numbers: a stocked sheave always ends in the bore it is machined to or the bushing it takes, so the parts at that size are AK64X1, AK64X15/16 and AK64H. The 1,011 endings below are the ones we hold. Read the series from the row and the ending from its cell, run the two together, and the result is the part number the link opens. Endings climb by sheave diameter, an H takes a Split Taper H bushing, and an X and a fraction is a finished bore machined to that size.

These are the sizes we hold now, not every size a series covers — the published ranges are in the tables further up. A size marked BULK or CLEAR PK is the same sheave in a different pack, and a size stated in millimeters is bored to that metric size rather than to the nearest inch.

Which bushed V-belt sheaves do we stock?

1,690 of them, in 25 groove sections. A bushed sheave number states its groove count first and its groove section next, so the table below gives, for each section, the groove counts we stock it in and how many sheaves that comes to. There are far too many numbers to print here, so the parts themselves stay in the V-belt sheaves category, which filters by groove count and bore.

A section is the belt the grooves are cut for, so B, C, TB and TC carry classical belts, 3V, 5V and 8V carry narrow belts, and a section written with letters on either side of one of those, such as B5V or R5V, is a combination groove. The counts are what we hold now and move with each price change. A further 10 parts filed in these two categories carry numbers neither table reads, and are listed in the V-belt sheaves and FHP sheaves categories rather than here.