Shaft Keyway Depth Calculator
This shaft keyway depth calculator is for calculating keyway depths from the outside diameter of a shaft to the bottom of a keyway. Once this is known, the cutter can be fed down to the required depth without taking any measurements other than that indicated by the graduations or scale on the machine.

To determine the total keyway depth one must calculate the height of the arc of the shaft which is designated as dimension A.  This shop aid will calculate dimension A after given the diameter of the shaft D, and the width of the key W.


1. Enter the width of key W.

2. Enter the diameter of shaft D.

3. Click Calculate to get dimension A.

4. Add A to the desired keyway depth H to get the total keyway depth.

W      D      A =

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A Right-angled Triangle Calculator and More handy Calculators can be found by clicking the Shop Aides menu item!

Note: Great care has been made to make sure this calculator is accurate. However, due to human error, the user agrees to accept full responsibility to verify that the calculated results meet their requirements before using them.