KEVOS® MAKEOS · Threads
Thread Rolling Set-up (Blank Diameter, Roll Size, Starts)
For rolling this metric thread with cylindrical dies, what blank diameter do I turn, how many starts must the rolls have to fit my machine, and what roll pitch diameter results?
Set-up for cylindrical-die thread rolling of an ISO metric thread: pitch diameter, thread height and stress area of the thread (as the metric thread tool), the blank diameter taken at about the pitch diameter, the roll pitch diameter and lead for the number of starts on the rolls (as the threading roll size tool), and the range of starts that gives a roll inside the machine’s roll diameter range.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Nominal diameter | mm | Nominal diameter of the metric thread. |
| Pitch | mm | Pitch of the thread. |
| Starts on the roll | Number of starts on each roll. | |
| Smallest roll pitch diameter for the machine | mm | Smallest roll pitch diameter the machine spindles accept. |
| Largest roll pitch diameter for the machine | mm | Largest roll pitch diameter the machine accepts. |
Method and formulas
- Pitch diameter d₂ = d − 0.6495P; external thread height h₃ = 0.6134P; stress area from d₂ and d₃ (as the metric thread tool).
- Blank diameter ≈ pitch diameter, adjusted on trial for full form.
- Roll pitch diameter = N_s (d₂ − h₃ ÷ 2) − h₃; roll lead = N_s × P (as the threading roll size tool).
- Example: turn the blank to about 10.863 mm; 10-start rolls have a 102.19 mm pitch diameter; 8 to 17 starts fit the machine.
Limitations
- Blank diameter is a starting value; material flow and the class of fit set the final size.
- Cylindrical dies; flat dies and planetary heads use other relations.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Set up a thread rolling machine
- Order thread rolls for a new thread
- Turn blanks for rolled threads
Who it is for
- Setters
- Manufacturing engineers
- Tool buyers
What you get
- Thread pitch diameter, height and stress area
- Blank diameter
- Roll pitch diameter, lead and suitable starts
Interpreting the result
- Rolls with more starts are larger and last longer, but must fit between the spindles.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2050–2051, 1867–1890. Topic reference; no source tables or recommended settings are reproduced.
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Open the Thread Rolling Set-up (Blank Diameter, Roll Size, Starts) calculator
