Describe more than the diameter
Provide length, wall thickness where relevant and the features available for gripping. A thin sleeve and a solid shaft with the same diameter are not equivalent workholding problems. Show any cosmetic or functional surfaces that cannot contact a fixture. Include the weight and any off-center attachments that affect support.
Define the coverage
A short identifier on one side differs from a graphic or scale extending around the circumference. Specify the start position, orientation and relationship to features such as flats or holes. If multiple marks must align, include the positional requirement. Ask the supplier how the part will be located and how the finished orientation will be inspected.
Review repeat loading
For recurring production, loading should be considered along with marking. An example trial can show whether the fixture reliably locates the same feature each time. Agree on how parts are identified before and after processing, especially where serial data is involved. Keep the approved workholding concept associated with the part revision so later geometry changes receive a review.