Mandrel
Glossary · Workholding & Setup
At a glance
- Category /
- Workholding & Setup
- Related /
- 2 terms
- Source /
- Written in the shop
A mandrel is a precisely sized shaft that a part is mounted on by its bore so that its outside features can be machined true to that bore.
In practice
Used when the bore is the important reference. The part is fitted onto the mandrel, and the mandrel is held between centres or in a chuck, so everything cut afterwards is concentric to the bore.
Why it matters
It is the standard answer to "this outside diameter has to run true to the bore". Trying to achieve the same by gripping the outside and hoping is how concentricity requirements get missed.
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