Spur gear module 4 z=21 with hub

Product Description

Spur gear module 4, z=21, with hub

Gear module 4, z=21, with hub - a robust component for building and repairing gear transmissions, reducers and rack drives (gear rack + gear). The gear is made of C45E steel (EN 10083-1); the involute tooth profile and 20° pressure angle ensure smooth, quiet meshing with gears or racks of the same module.

Technical data

Frequently asked questions

Can module gears be bored out for non-standard shafts?

Yes, most module gears are supplied with a pilot bore, which allows them to be freely bored out, keyway-slotted and precisely fitted to the specific shaft size at the customer's premises.

How can you recognise a manufacturing defect in a gear when receiving the goods?

It is worth checking the radial runout (the gear should not "wobble" on the shaft), the uniformity of the pitch between teeth and the smoothness of the tooth surface - visible burrs, dents or uneven pitch are a signal to file a complaint.

Does a module gear require constant lubrication?

Enclosed gears (in speed reducers) run in oil or grease, while open systems (gear + rack) require periodic manual lubrication - without it, friction and tooth wear increase many times faster.

What is the module of a gear and how do you measure it correctly?

The module (m) is the basic parameter defining tooth size, i.e. the ratio of the pitch diameter to the number of teeth. The simplest way to measure it in workshop conditions is to measure the outside diameter of the gear (Dz), count the teeth (Z) and use the formula: m = Dz / (Z + 2).

Where is this product used?

Typical applications include conveyor drives, packaging machines, industrial automation and positioning systems using a gear and gear rack pair.

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.