BIZOMAT MAKEOS · Manufacturing
Tapping Feed and Thread Lead
What synchronous feed matches this thread lead?
Relate thread pitch, number of starts and spindle speed to axial tapping or threading feed.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Thread pitch | mm | Axial spacing of adjacent thread crests from the drawing; convert TPI first if needed. |
| Thread starts | starts | Number of independent helices on the thread. |
| Spindle speed | rpm | Actual machine setting, checked against tooling and machine limits. |
| Axial feed distance | mm | Travel during the forward feed; not the required full-thread depth. |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Thread pitch
- What it is
- The axial distance between neighbouring thread crests, as given in the thread designation (for example the 1.5 in M10 × 1.5).
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.000001 mm to 1000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1.5 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Lead and synchronous feed are directly proportional to pitch.
- Get it right
- Imperial threads are given in TPI: pitch in mm is 25.4 divided by TPI.
What this means: Thread starts
- What it is
- The number of separate thread helices wound side by side on the thread. Most screws and taps are single-start.
- Units and format
- Enter a number in starts: a number of thread starts. The form accepts 1 starts to 100 starts. Use a whole number. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1 starts as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Lead and feed are directly proportional to the number of starts.
- Get it right
- Count the thread ends visible at the end of the screw; a multi-start thread moves several pitches per turn.
What this means: Spindle speed
- What it is
- The spindle speed used while tapping or threading.
- Units and format
- Enter a number in rpm: revolutions per minute. The form accepts 0.001 rpm to 1000000 rpm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1000 rpm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Synchronous feed is directly proportional to spindle speed.
- Get it right
- For rigid tapping the feed must follow the spindle exactly; check the controller feed mode.
What this means: Axial feed distance
- What it is
- The distance the tap travels forward along its axis during the feed stroke before reversing.
- Units and format
- Enter a number in mm: millimetres. The form accepts 0.001 mm to 1000000 mm. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 15 mm as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- It changes only the forward feed time, which is directly proportional to it.
- Get it right
- This is the programmed feed distance, which can differ from the required full-thread depth because of the tap lead-in.
Method and formulas
- Lead = pitch × starts.
- Synchronous feed (mm/min) = RPM × lead.
- Forward feed time = distance ÷ feed. Example: 1.5 mm single-start at 1000 rpm gives 1500 mm/min; 15 mm takes 0.6 s.
Limitations
- No tap-drill selection, thread tolerance, torque prediction or controller-specific cycle is provided.
- Excludes reversal, acceleration, chamfer allowance and return.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- rigid tapping
- thread lead
- multi-start
Who it is for
- CNC programmers
- Machinists
What you get
- Thread lead
- Synchronous feed
- Forward feed time
Interpreting the result
- Check whether the control expects feed per minute or feed per revolution and verify synchronisation.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1071, 1808, 2027–2044. Topic reference; no source tables or recommended settings are reproduced.
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