Precision Acme Screws - How Precise?
The Answer: Lead Accuracy
Lead accuracy is the difference between the actual distances traveled versus the theoretical distance traveled based on lead. Obviously, the better the lead accuracy, the better precision you have. Keep reading for examples of lead accuracy calculations for imperial and metric precision acme screws.
1. Inch Acme Lead Screws
Example
A screw with a .5 inch lead and ±0.004 inch per foot lead accuracy rotated 24 times theoretically moves the nut 12 inches. 24 Revolutions X .500 inches per revolution = 12.000 inches of travel with a Lead Accuracy of .004 per foot; actual travel could be from 11.996 to 12.004 inches.
Inch Acme Screw Assemblies
- Lead Accuracies
- ± 0.004 in/ft - Standard Rolled
- ± 0.001 in/ft - Precision Rolled
- ± 0.0005 in/ft - Precision Ground
- Standard diameters from 0.125" to 6" (larger diameters up to 14")
- Standard leads from 0.062" to 1.000."
- Right-hand and Left-hand Alloy and Stainless Steel Screws
- Bronze or Plastic nut
Inch Twin-Lead Acme Screw Assemblies
- Lead Accuracies:
- ± 0.004 in/ft - Standard Rolled
- Standard diameters from 0.25" to 3" (larger diameters up to 14")
- Standard leads from 0.083" to 1.000."
- Right-hand and Left-hand Thread on a single Alloy Screw
- Bronze or Plastic nut
2. Metric Lead Screws
Example
A screw with a 12 mm lead and ±100 µm per 300mm lead accuracy rotated 25 times theoretically moves the nut 300 mm. 25 Revolutions X 12 mm per revolution = 300 mm of travel with a Lead Accuracy of ±100 µm per 300mm, actual travel could be from 299.9 mm to 300.1 mm.
Metric Acme Screw Assemblies (Speedy)
- Lead Accuracies
- ± 17.5µm/25mm Standard Rolled
- Standard diameters from 5mm to 36mm
- Standard leads from 5mm to 200mm
- Right-hand and Left-hand Alloy and Stainless Steel Screws
- Bronze or Plastic nut
Metric Acme Screw Assemblies (ISO)
- Lead Accuracies:
- ± 6.25µm/25mm ISO Rolled
- Standard diameters from 10mm to 65mm
- Standard leads from 3mm to 12mm
- Right-hand and Left-hand Alloy and Stainless Steel Screws
- Bronze or Plastic nut
Acme Lead Screws Precision Applications
What types of applications require high-accuracy lead screws? Several industries that require the highest precision possible include medical and diagnostics include:
- Medical and diagnostic applications like syringe pumps and imaging technology.
- Military and defense applications like missile fin actuation and tank sighting.
- Semiconductor applications such as wafer handling and thermal management.
- Communication applications include satellite positioning and tracking antennas.
- Electronics applications like limiting switches and sensors.
- Robotic applications like cobots and drone control actuation.
- These are just a few examples that demand the precision that acme screws can deliver.
Wrapping Up
So what puts the precision in Precision Acme Lead Screws? The differentiation of the actual linear distance traveled, and the theoretical distance traveled is based on lead. We'd be happy to help you select an acme screw to provide precise moments and positioning in your next linear motion project.
Contact us today!
