Specsheet
Concentricity matters when you want shafts and bushes to run true. Getting it right stops vibration, wear, and callbacks for repair.
By Mr Riaan Swanepoel, MD, Specs
Concentricity is about keeping a shaft and its mating bore sharing the same centre, so parts rotate smoothly with no wobble or uneven wear. On South African floors, especially in repair and custom runs, a bush or bearing that is even a fraction off-centre can cause vibration, noise, and premature failure.
Unlike basic diameter checks, concentricity means the whole fit is true to one axis. A shaft that runs out, or a bore that's off, turns into callbacks and downtime. With smaller teams and mixed work, it is easy for a key fit decision to get lost between drawing, machine, and bench.
In our experience, getting consistent concentricity in the workshop is a matter of clear habits more than fancy gauges. Here is a step-by-step to pin up near the lathe or mill.
If you are not sure where your reference axis should be, or how to clock a part, ask us. We can show you the best way for your lathe, mill, or press. It is also worth checking if your measuring kit is accurate and if your machine beds or chucks are worn or need service.
In coastal cities like Durban or Gqeberha, ask about protecting your reference surfaces from rust, as even a small amount can throw off accurate concentricity. We can advise on covers and oiling routines.
One of the biggest mistakes is assuming the chuck or vice is running perfectly true, always check runout before starting. Another common slip is skipping the final check after assembly, especially on urgent jobs.
If power cuts hit during a job, always re-home your axes and double-check your zero and datum after restarting. Do not rely on memory or rough marks. It is easy to lose a reference and scrap a part.
Continue with equipment, bays, or use our contact form.
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