Sprocket 12B-2 z=21 with hub, hardened

Product Description

Sprocket 12B-2 z=21, hardened hub

Duplex sprocket 12B-2 with hardened hub, 21 teeth - dedicated to a chain with a pitch of 3/4" (19.05 mm). The material is carbon steel C45E (EN 10083-1), and the teeth undergo induction hardening to 45-55 HRC - in accordance with DIN 8187 / ISO 606; the hub retains a lower core hardness, so it can be machined safely.

Technical data

Frequently asked questions

When is it worth using a clamping bush (Taper Bush) for a sprocket?

Wherever fast assembly matters. A clamping bush eliminates the need for laborious boring of the hub and cutting of a keyway - you insert the sprocket, tighten the screws and the machine is back in operation within minutes.

When does tooth wear (the "shark fin" profile) mean the sprocket must be replaced?

If the teeth resemble pointed, tilted shark fins, the sprocket must be replaced immediately. Operating on such a profile can damage even a brand-new chain within a dozen or so days.

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.

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.

Where is this product used?

12B-2 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.