Sprocket 20B-3 z=38 with hub, Cast iron

Product Description

Sprocket 20B-3 z=38, with cast iron hub

Sprocket 20B-3, triplex (three-strand), with 38 teeth and a hub - pitch 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

In what cases are multi-strand sprockets used?

They are used to drive multi-strand chains in heavily loaded machines where there is no room for a wider sprocket with a larger pitch. Several strands distribute the load evenly, preventing premature chain breakage.

How can a sprocket and chain be protected against corrosion during storage?

After cleaning off any dirt, it is advisable to apply a layer of preservative grease or anti-corrosion oil and store the sprocket in a dry place not exposed to condensation. In the steel version (without coating), even a short damp break in the workshop can cause a rusty film on the tooth surfaces.

How can you tell whether a sprocket is still fit for further service or already due for replacement?

It is worth checking the tooth profile for visible chipping or the characteristic "hooked" shape, and also measuring the pitch circle diameter and comparing it with the catalogue dimension of a new sprocket. If the difference is visually noticeable or the chain starts to "jump", the sprocket is due for replacement.

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.

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?

20B-3 sprockets are used in industrial drive transmissions: conveyors, feeders, packaging machines and production lines where precise, repeatable torque transmission 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.