Timing pulley H300 z=118 for 3" (76.2 mm) belt, cast iron, pilot bore

Product Description

Timing pulley H300 z=118 for 3" (76.2 mm) belt, cast iron, pilot bore is a timing (synchronous) pulley for belts with the imperial H profile: pitch 1/2" (12.7 mm), 118 teeth, belt width up to 3" (76.2 mm). It is made of EN-GJL-200 grey cast iron.

The pitch diameter is 477.02 mm and the outside diameter 475.65 mm. The pulley has a hub with a pilot bore Ø28 mm, which is bored out to the shaft size and completed with a keyway or a set screw hole.

Technical data

Applications

Medium and high power industrial drives, agricultural machinery, machine tools, pumps, compressors and conveyors.

Frequently asked questions

Which timing pulley has the H300 profile, 118 teeth and a pitch diameter of 477.02 mm?

This is the timing pulley H300 z=118 for 3" (76.2 mm) belt, cast iron, pilot bore. The outside diameter (over the tooth tips) is 475.65 mm. The pitch diameter is calculated as Dp = pitch × z / π = 12.7 × 118 / π.

Which timing belt fits this pulley?

A belt with the imperial H profile (pitch 1/2" = 12.7 mm) and a width of up to 3" (76.2 mm) - in the belt designation the width 3" is written as 300 (e.g. belt 450H300, where 450 is the belt length in tenths of an inch). A narrower belt of the same profile will also run correctly.

Does this pulley work with a metric T10 or HTD belt?

No. The H profile has an imperial pitch of 12.7 mm and a trapezoidal tooth shape, so it does not mesh correctly with metric belts (T, AT) or with HTD belts with rounded teeth. The pulley and the belt must have the same profile.

How do I prepare the bore for the shaft?

The pilot bore Ø28 mm is bored out on a lathe to the shaft size (usually to tolerance H7) and a keyway is cut to DIN 6885. The pulley is secured axially with a set screw in the hub. The maximum bore depends on the hub diameter (120 mm) - enough wall thickness must remain after machining.

How do I calculate the ratio of a drive with this pulley?

The ratio is the number of teeth of the driven pulley divided by the number of teeth of the driving pulley, e.g. 118 / 18 = 6.56. A timing belt drive has no slip, so the ratio is constant.

How does a cast iron pulley differ from a steel one?

EN-GJL-200 grey cast iron damps vibration well and is used mainly for larger pulleys. C45 steel pulleys are chosen for smaller diameters and where shock loads occur.

What does the lead time depend on?

When ordering, please check the current stock level of this pulley - the lead time depends on it and is clearly stated according to the quantity available in each warehouse. The stock level is shown above the product price and may differ between warehouses.

Product photos are for illustration purposes only.