Sprocket 12B-3 z=21 with hub

Product Description

Sprocket 12B-3 z=21, with hub

Triplex (three-strand) sprocket 12B-3 with hub, 21 teeth - designed for chain with a pitch of 3/4" (19.05 mm). Manufactured in accordance with DIN 8187 / ISO 606 from C45E structural steel (EN 10083-1), without tooth hardening - as a Polish manufacturer, Ozdowski supplies an economical version that is fully dimensionally interchangeable with the hardened variant of the same pitch.

Technical data

Frequently asked questions

How do I check the radial and axial runout of a sprocket after mounting it on the shaft?

A dial indicator on a magnetic stand is used for the measurement. Place the tip against the circumference of the sprocket or its side face, rotate the shaft and check the deviations. Excessive runout indicates faulty installation or a damaged shaft.

What does the marking "z=X" on a sprocket mean and why is it so important when ordering?

"z" is the number of teeth of the sprocket - together with the pitch and the number of chain strands, it unambiguously defines the sprocket geometry (pitch circle and outside diameter). Ordering a sprocket with the wrong "z" usually means that it will not work correctly with the second sprocket already in the machine, and a different transmission ratio than intended will result.

Do I need to select dedicated bearings for a sprocket with hub?

A sprocket with hub mounted with a key does not require its own bearings - the load is carried by the bearings of the shaft on which the sprocket is mounted. A dedicated bearing built into the sprocket is only needed for tensioning or guide sprockets mounted on an axle without its own drive.

Can I replace a simplex sprocket with a duplex one without changing the other drive components?

No - switching to a duplex chain and sprocket requires replacing the entire set (the sprockets on both sides of the drive and the chain) with a duplex version of the same pitch, because the rim spacing and chain width differ from those of the simplex version.

Where is this product used?

12B-3 sprockets operate in drives of construction machinery, goods lifts, aggregate conveyors and woodworking machines - wherever tooth durability under load matters.

When placing your order, please check the current stock level of this gear - the lead time depends on it and is clearly stated according to the quantity available in the given warehouse.

Product photos are for illustrative purposes only.