Calculator Inputs
Example Data Table
| Pitch | Starts | Lead Per Revolution | RPM | Linear Feed | Common Use |
|---|---|---|---|---|---|
| 2 mm | 1 | 2 mm | 300 | 600 mm/min | Fine positioning |
| 2 mm | 2 | 4 mm | 300 | 1200 mm/min | Faster slide travel |
| 8 TPI | 1 | 3.175 mm | 300 | 952.5 mm/min | Imperial screw setup |
Formula Used
Lead: Lead = Pitch × Number of starts.
TPI pitch: Pitch in inches = 1 ÷ TPI.
Travel revolutions: Revolutions = Travel distance ÷ Lead.
Linear feed: Feed = Screw RPM × Lead.
Required RPM: RPM = Desired feed ÷ Lead.
Steps per unit: Steps per unit = Motor steps × Microsteps × Drive ratio ÷ Lead.
Distance per step: Distance per step = Lead ÷ Steps per screw revolution.
Thrust from torque: Force = 2π × Efficiency × Torque ÷ Lead in meters.
Torque for load: Torque = Load × Lead in meters ÷ 2π × Efficiency.
How To Use This Calculator
Choose the unit system first. Enter pitch directly or use threads per inch. Add the number of starts because this changes lead. Enter travel distance, rpm, feed, motor step data, backlash, torque, efficiency, and load. Press calculate. Review the result above the form. Download the CSV or PDF report when needed.
Lead Screw Distance Per Revolution Guide
Lead Screw Distance Planning
A lead screw changes rotary motion into straight motion. The distance moved in one full turn is called lead. Lead depends on pitch and the number of starts. A single start screw moves one pitch per turn. A two start screw moves two pitches per turn. This calculator helps compare those details before hardware is chosen.
Why Distance Per Revolution Matters
Distance per revolution controls speed, force, and resolution. A larger lead moves the nut farther with each turn. It can raise travel speed, but it lowers mechanical advantage. A smaller lead gives finer motion. It can also demand more revolutions for the same travel. CNC slides, actuators, jigs, printers all depend on this balance.
Motor And Drive Effects
The screw is only one part of the motion chain. Motor step angle, microstepping, and belt ratio also change final resolution. The calculator estimates steps per unit and distance per step. It also converts travel distance into revolutions. This helps check whether the motor can complete the required move without wasting time or losing accuracy.
Speed And Feed Checks
Linear feed is found from screw lead and revolutions per minute. If the rpm is fixed, the calculator predicts travel speed. If a desired feed rate is entered, it estimates the rpm required. These checks are useful when setting machine limits, selecting drivers, or testing motion programs.
Force And Torque Review
Lead screw force depends on torque and efficiency. Friction reduces the ideal output force. The calculator uses efficiency to estimate thrust from torque. It estimates torque needed for an axial load. A safety factor is included, so the suggested torque is more practical. This does not replace machine design review. It gives a clear starting point.
Backlash And Practical Accuracy
Backlash can reduce positioning accuracy when direction changes. Entering backlash helps show the likely lost motion. The value can be used for notes, compensation planning, or maintenance checks. Measure backlash under real load when possible.
Use The Results Carefully
The results are estimates. Real screws bend, wear, heat, and deflect. Lubrication, bearing alignment, nut style, and load direction also matter. Use the CSV or PDF report to compare options. Then verify the chosen screw with supplier data.
FAQs
What is lead screw distance per revolution?
It is the linear distance traveled by the nut during one full screw turn. It is also called lead. For a single start screw, lead equals pitch. For multi-start screws, lead equals pitch multiplied by starts.
Is pitch the same as lead?
Pitch and lead are the same only for a single start screw. Pitch is thread spacing. Lead is actual travel per revolution. Multi-start screws move farther per turn, so lead becomes larger than pitch.
How do I calculate lead from TPI?
First convert TPI into pitch. Pitch in inches equals one divided by TPI. Then multiply that pitch by the number of starts. Convert inches to millimeters when needed by multiplying by 25.4.
Why does the number of starts matter?
Starts are separate thread paths around the screw. More starts increase travel per turn. This can improve speed, but it may reduce mechanical advantage and holding force. Always match starts with load and resolution needs.
How does lead affect motor steps?
A smaller lead gives more steps per millimeter. This improves theoretical resolution. A larger lead gives fewer steps per millimeter. That can increase speed, but each step moves the axis farther.
Can this calculator estimate feed rate?
Yes. Enter screw rpm and lead data. The calculator multiplies rpm by lead. The result is linear feed per minute. It also estimates the rpm needed for a desired feed rate.
Does backlash change lead screw distance?
Backlash does not change the screw lead. It affects real positioning after direction changes. The calculator converts backlash into step loss, so you can estimate compensation or check mechanical wear.
Are torque and thrust results exact?
No. They are estimates based on lead and efficiency. Real thrust depends on friction, lubrication, bearings, nut design, alignment, and wear. Use these values for planning, then verify with hardware data.