Part design and parts made from samples

Plenty of equipment outlives its paperwork. The manual is gone, the maker has stopped supporting the model, or the part was always made one at a time. A sample in your hand is enough to begin, and the shop handles the steps between that sample and a finished replacement.

At a glance

• A sample, a worn original or a sketch is enough to start
• The original is measured and the part drawn up
• Help choosing the material and the fit
• The drawing is kept for the next time

How is a part drawn up from a sample?

In plain words, the shop measures the original. Diameters, lengths, hole positions, threads and fits are taken with gauges and calipers and written down. If the sample is worn, the measurements are taken from the unworn areas and corrected for the loss.

From those numbers the part is drafted, on paper or on a computer, so it can be machined and checked. The finished part is compared back to the sample, and the drawing is kept in case you need the part again.

Material and fit decisions

A sample shows shape, but not always what it is made from or how tightly it fits its neighbor. Your knowledge of how the machine runs tells us a good deal. Where a part sees wear, the question becomes whether to copy the original material or choose one that lasts longer.

The sizes a part needs to hold often follow standard fits. The glossary entry on interference fits explains the idea, and the tolerance entry covers allowed variation.

• Copy the original material, or choose one that wears better
• Match the fit of the mating part, not the worn sample
• Decide which surfaces need a finish and which do not

Design help for new ideas

Not every job starts with an old part. Sometimes the customer has a problem and a rough idea of the answer. The shop's own words are: "We can also assist you in designing your product or part." For an automated fixture, for example, that assistance is part of the job, as described on the automated machines and fixtures page.

If the idea is still unproven, begin with a prototype and refine the design from there.

What to bring or send

The ideal sample is the part itself. Bring it to 4812 Longley Ln, or send photos with a ruler in the shot, the machine it comes from, and the sizes you can measure. The photographing and measuring article shows how. Use the quote request or call (775) 359-5570, Monday to Friday, 7:00 am to 3:30 pm. See also the answer on making a part without a drawing.