KEVOS® MAKEOS · Threads
Threading Roll Pitch Diameter
What pitch diameter should a single- or multiple-start threading roll have for this screw thread?
Pitch diameter of a threading roll for a screw machine from the pitch diameter of the thread to be rolled, the single depth of thread and the number of starts on the roll, by the handbook formula, with the roll lead.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Pitch diameter of the screw thread | mm | Pitch diameter of the thread to be rolled. |
| Single depth of thread | mm | Single depth of the thread form. |
| Starts on the roll | Number of single threads (starts) on the roll, chosen to give a convenient roll diameter. | |
| Thread pitch | mm | Pitch of the screw thread. |
Method and formulas
- D = N (d − T ÷ 2) − T, as in the handbook (a double roll for a ½-in. thread with d = 0.4500 in and T = 0.0499 in gives about 0.800 in).
- Roll lead = N × thread pitch, so the helix angles of roll and work nearly match.
- Example: a 2-start roll for a 11.43 mm pitch diameter needs a 20.325 mm pitch diameter.
Limitations
- One screw machine maker’s recommendation; follow the roll supplier where it differs.
- Single-start roll for external threads on screw machines.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Specify a threading roll for an automatic screw machine
- Choose the number of starts for a practical roll diameter
- Check a supplied roll against the thread
Who it is for
- Screw machine setters
- Tooling engineers
- Machinists
What you get
- Roll pitch diameter
- Roll lead
- Roll diameter ratio
Interpreting the result
- Add starts to obtain a larger, stronger roll that still matches the work’s helix angle.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2050–2051. 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.
