Measuring eccentricity of the ends of a shaft

[bamek]

Hi!
My name is Daniel and I'm new to this forum.

I work as a mechanical engineer at a machining workshop in Norway. We are currently producing some steel shafts that require a high level of accuracy.

The shafts are about 1500mm long, and has a diameter of 40mm h6 (+0,000mm, -0,011mm) all over. The ends of the shaft are required to be eccentric within 0,02mm (I don't know if this is the right way to explain it, but I hope you understand.)

Because of the length and the difficult tolerance of the diameter, the shaft has to be machined in two operations, and this makes the eccentricity hard to achieve, but I believe that I have found a way to machine the part within all given tolerances.

My question is, does anybody have an idea how I can measure the eccentricity of the ends accurately?

Best regards
Daniel

 

[pantaz]

Precision v-blocks and a dial/digital indicator of sufficient resolution -- generally 10 times the required precision. (E.g., For a required 0.02mm, an indicator of 0.002mm resolution.)

 

[Bandit127]

Welcome to the forum Daniel.

Just to check my understanding here... By eccentricity do you mean that the ends of the bars have to be on the same centreline to within a total of 0.02 mm?

If so, the V blocks and indicator might work but you will need to support one half of the shaft while measuring the end of the other.