Many gears inside a machine have no technical drawing. The builder no longer supplies spares, the drawing cannot be found, or the part was made locally years ago. In that case the practical route is to use the old part as a sample.
How production from a sample works
Module, tooth count, outside diameter, face width, bore and keyway are taken off the sample. Worn or broken teeth are reconstructed from the sound teeth using the standard tooth profile. The new part is then produced to those dimensions.
Before you send the sample
- Clean the part: oil and dirt affect measuring accuracy. Dry it and pack it clean.
- Do not forget the mating gear: if the part is badly worn, sending the mating gear too (or its dimensions) makes it much easier to get the result right.
- Describe the duty: the machine, the speed and the load the gear runs under drive the material and heat treatment choice.
- Pack it well: use a sturdy box and fill the voids so the sample is not damaged in transit.
Get a quote from photos first
You can get an indicative quote from photos before shipping anything. When taking the photos:
- Shoot the part square on, next to a ruler or caliper.
- Add a close-up where the teeth are clearly visible.
- Photograph the bore, the keyway and the hub separately.
- Use good, shadow-free light.
We send you the sample delivery address once you approve the quote.
The limits of reverse engineering
Dimensions taken from a sample may not reproduce the tolerances of the original drawing exactly. For precision mechanisms — machine tool gearboxes, for example — state your tolerance and surface finish expectations in the request. The chemical composition of the material cannot be read off a sample either; we recommend a material suited to the duty instead.
Can you have your sample back?
Yes. Ask for the sample to be returned with the new part or collected in person — a line in the description field of your request is enough.