Sprocket 20B-2 z=76 with hub, Cast iron

Product Description

Sprocket 20B-2 z=76, with cast iron hub

Sprocket 20B-2 with hub, 76 teeth, duplex - a product matched to chain with a pitch of 31.75 mm (1 1/4"). Cast iron version of the sprocket - the tooth geometry is identical to the steel version with the same pitch and number of teeth; the bore in the hub is a pilot (preliminary) bore, and the exact size is achieved by turning.

Technical data

Frequently asked questions

What is the set screw hole in the hub for?

The threaded hole in the hub is used to screw in a headless screw (a so-called grub screw). It secures the sprocket against axial displacement along the shaft during machine vibration.

How does a sprocket with hardened teeth differ from the standard version (non-hardened)?

The hardened version has teeth induction-hardened to 45-55 HRC, which extends service life in drives operating continuously and under heavy load. The standard version (non-hardened) is cheaper and fully adequate for applications with moderate load or intermittent operation - our catalogue offers both variants for most pitches and numbers of teeth.

Do a newly fitted chain and sprocket require running-in after installation?

After installation, it is worth running the drive for a while without full load, observing the smoothness of operation and the bearing temperature - this allows installation errors (e.g. misalignment) to be detected before full load is applied. The tooth profile of the sprocket itself does not require running-in if the sprocket and chain have matching pitch and are made in accordance with the standard.

Can a sprocket with a technological bore be installed without additional machining?

No - the technological bore is deliberately too small to fit a typical shaft. It must be bored on a lathe to the required diameter and, if necessary, a keyway cut according to the requirements of the specific machine.

Is a duplex sprocket the same as a tandem sprocket (for two single chains)?

No, even though they look very similar. A tandem sprocket is also a single, monolithic sprocket, but with a different (wider) spacing of the toothed rims - designed specifically for two independent simplex chains running in parallel. This duplex sprocket has a rim spacing matched to a single duplex chain, in which both strands are integrated with each other. Using a duplex sprocket for two single chains is a mistake - the spacing is too narrow and the chains will rub against each other, which leads to accelerated wear and, in extreme cases, to serious drive failure.

Does a cast iron sprocket require a different chain than a steel sprocket of the same pitch?

No - the tooth geometry and pitch are identical to those of the steel version of the same size, so the cast iron sprocket works with the same chain. The difference lies in the material of the hub and rim: cast iron dampens vibrations better and is cheaper, but withstands impacts and operation at high rotational speeds less well than steel.

Where is this product used?

Typical applications of the 20B-2 sprocket: drives for pumps, mixers and industrial fans, as well as control systems for industrial gates and roller shutters, where resistance to continuous operation is required.

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.