Hollow Form Calculator

Wall thickness and depth from form dimensions.

Outer diameter (in)

Overall height (in)

Opening diameter (in)

Target wall thickness (in)

Neck length (in)

Tab to move between fields

Interior diameter (in)

5.5

Interior depth (in)

6.75

Interior volume (cu in)160.4

Tool reach needed (in)9.75

Depth-to-opening ratio3.38

Difficulty (1-3)2

Min tool bar dia (in)0.61

Max hollowing RPM667

Shell Volume65.83

Removed Weight (lbs)3.71

How to Use This Calculator

How the result changes with Outer diameter (in)

Outer diameter (in): Maximum outer diameter of the vessel.
Overall height (in): Total height of the form from base to rim.
Opening diameter (in): Diameter of the top opening for tool entry.
Target wall thickness (in): Desired uniform wall thickness (3/16" to 3/8" typical).
Neck length (in): Length of the neck/collar above the hollow body.

Interior diameter (in): Maximum internal width of the hollow cavity.
Interior depth (in): Depth of the hollow cavity.
Interior volume (cu in): Approximate interior cavity volume.
Tool reach needed (in): Minimum hollowing tool bar length needed (depth + neck + 2" clearance).
Depth-to-opening ratio: Higher ratio = harder to hollow. Under 2 is manageable, 2-4 challenging, over 4 expert.
Difficulty (1-3): 1 = manageable, 2 = challenging, 3 = expert level.
Min tool bar dia (in): Minimum tool bar diameter for rigidity at this reach.
Max hollowing RPM: Recommended maximum RPM for hollowing operations.

Identify Input Parameters
4 parameters
Outer diameter (in) = 6, Overall height (in) = 8, Opening diameter (in) = 2, Target wall thickness (in) = 0.25 = 5 input(s) provided
Calculate Interior diameter
Interior diameter = outerDiameter - 2 * targetWall
5.5 = 5.5
Calculate Interior depth
6.75 = 6.75
Calculate Interior volume
Interior volume = π * interiorRadius * interiorRadius * safeInteriorDepth
160.4 = 160.4
Calculate Tool reach needed
Tool reach needed = safeInteriorDepth + neckLength + 2
9.75 = 9.75