Timing pulley H300 z=30 for 3" (76.2 mm) belt, C45 steel, pilot bore

Product Description

Timing pulley H300 z=30 for 3" (76.2 mm) belt, C45 steel, pilot bore is a timing (synchronous) pulley for belts with the imperial H profile: pitch 1/2" (12.7 mm), 30 teeth, belt width up to 3" (76.2 mm). It is made of C45 steel.

The pitch diameter is 121.28 mm and the outside diameter 119.9 mm. The pulley has a hub with a pilot bore Ø19 mm, which is bored out to the shaft size and completed with a keyway or a set screw hole. The flanges (Ø128 mm) guide the belt and stop it running off the pulley.

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, 30 teeth and a pitch diameter of 121.28 mm?

This is the timing pulley H300 z=30 for 3" (76.2 mm) belt, C45 steel, pilot bore. The outside diameter (over the tooth tips) is 119.9 mm. The pitch diameter is calculated as Dp = pitch × z / π = 12.7 × 30 / 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 Ø19 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 (80 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. 30 / 18 = 1.67. A timing belt drive has no slip, so the ratio is constant.

What are the flanges for?

The flanges guide the belt and prevent it from running off the pulley. In a typical drive it is enough for one of the two pulleys, usually the smaller one, to have flanges.

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.