KEVOS® MAKEOS · Threads
Helical Milling Lead and Change Gears
What lead does this helix have, and which change gears cut it on the dividing head?
Lead of a helix from the work diameter and helix angle, the table swivel angle, and the closest compound change-gear train between the table feed screw and the dividing head.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Work diameter (pitch diameter for gears) | mm | Diameter at which the helix angle is specified (pitch diameter for helical gears). |
| Helix angle (from the axis) | ° | Helix angle measured from the work axis. |
| Lead of the machine | mm | Table travel for one dividing-head spindle turn with equal gears (254 mm = 10 in on many machines). |
| Change gears available | choice | Change gears available. |
Method and formulas
- Lead = π D ÷ tan β.
- Gear ratio (driven product ÷ driver product) = required lead ÷ machine lead.
- Search all four-gear combinations of the set for the closest ratio.
- Example: 60 mm at 30° needs a 326.48 mm lead; drivers 24 and 56, driven 24 and 72 (error 0.026814%).
Limitations
- Gear fit on the quadrant is not checked.
- The swivel is set to the helix angle at the cutting diameter.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Mill helical gears, flutes and cams
- Find change gears for a required lead
- Check the lead error of a gear train
Who it is for
- Machinists
- Toolmakers
What you get
- Required lead
- Table swivel angle
- Best compound gear train and lead error
Interpreting the result
- Multiply the percentage error by the face width to see the lead error over the part.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2060–2062, 2205. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
