Sprocket 20B-2 z=45 with hub, Cast iron

Product Description

Sprocket 20B-2 z=45, with cast iron hub

The sprocket 20B-2 shown is a duplex sprocket with 45 teeth, made with a hub, for chain with a pitch of 1 1/4" / 31.75 mm. The sprocket is made of grey cast iron - a traditional material for sprockets in applications with moderate loads and lower rotational speeds; the bore in the hub is a pilot bore intended to be machined to the shaft size.

Technical data

Frequently asked questions

What does the pitch of a sprocket mean and how can it be checked?

The pitch of a sprocket corresponds to the chain pitch - it is the theoretical distance between the centres of adjacent teeth on the pitch circle. The easiest way to check it is to place a section of matching chain on the sprocket - it should sit perfectly, without tension.

How do you cut a keyway in the hub of a sprocket?

We cut keyways precisely on slotting machines according to DIN 6885. If you do it yourself, maintain axial alignment and the correct width and depth of the keyway so that the key sits securely and is not sheared off.

How do sprockets for roller chains differ from sprockets for toothed chains (silent chain)?

A sprocket for roller chain has a rounded tooth root matched to the chain roller (profile according to DIN 8187), whereas a sprocket for toothed chain (silent chain) has a flat, trapezoidal tooth profile that engages the chain plates instead of rollers. These two systems are not interchangeable.

Will a sprocket from another manufacturer work properly with the chain I already have?

If the sprocket is made to the same standard (DIN 8187/ISO 606) and has the same pitch and number of strands, it should work properly with a chain of another brand - that is the purpose of standardisation in this industry. However, differences between manufacturers may concern, for example, hub dimensions or material, so these parameters are worth checking separately.

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.