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Automotion supply a large range of mechanical components to design engineers and special purpose machine builders. We specialise in linear rail systems, lead and ball screws, mechanical precision components and rotary parts. Our parts are fully listed on our website, where cad files can be downloaded and parts ordered. We hold a lot of product in stock.

 

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we have up-to-date live stock and pricing

Up-to-date pricing & live stock!

We have special prices on large order quantites

Special pricing on large orders!

3D CAD drawings available on selected products

3D CAD drawings to Download

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Click to download Lead screws series

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Click to download Ball screws series

(file size 1 MB)

Download Critical RPM Graphs

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Download Critical Load Graphs

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Lead Screws and Ball Screws

What is a Lead Screw?

A lead screw is a screw which translates rotary motion into linear motion. Normally used as the driving mechanism in horizontal or vertically driven applications aided by linear guides for supports. They are described by diameter and pitch or lead. The pitch or lead is the amount of travel you get, or distance the nut travels along the screw for every complete revolution. They can be operated manually or motorised.

Right hand steel lead screws

Steel Lead Screws - L1320
Steel trapezoidal lead screws. TR threads, standard right hand threads 10 to 100mm.

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Lead screws full range

Right hand stainless steel lead screws - L1322

Stainless Steel Lead Screws - L1322
Stainless steel trapezoidal lead screws (316 s/s). TR threads, standard right hand threads 10 to 70mm.

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Lead screws full range

Steel RH and LH Lead Screws

Steel RH & LH Lead Screws
Rolled trapezoidal steel lead screws - Left and right hand thread.

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Lead screws full range

Cylindrical bronze nuts for lead screws - L1330

Cylindrical Bronze Nuts - L1330
Cylindrical bronze lead screws nuts - for trapezoidal threads.

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Cylindrical nuts full range

Flanged bronze nuts for lead screws - L1331

Flanged Bronze Nuts - L1331
Flanged bronze lead screws nuts - for trapezoidal threads.

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Flanged nuts full range

Square bronze nut for lead screws

Square Bronze Nut with Through Holes - L1334
Square bronze lead screws nuts - for trapezoidal threads.

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Nuts full range

Hexagon steel nuts - L1338

Hexagon Steel Nuts - L1338
Steel hexagonal lead screws nuts - for trapezoidal threads.

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Nuts full range

Cylindrical steel nuts for lead screws - L1339

Cylindrical Steel Nuts - L1339
Steel cylindrical lead screws nuts - for trapezoidal threads.

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Nuts full range

Precision rectangular nut lead screws - L1347

Rectangular Nut Lead Screws - L1347
High precision lead screws with square acetal nuts.

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Lead screws full range

Precision round nut lead screws - L1348

Round Nut Lead Screws - L1348
High precision lead screws with flanged acetal nuts.

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Lead screws full range

High Precision Lead Screws - L1349

High Precision Lead Screws With Flanged Nut - L1349
High precision lead screws with flanged nut. Stainless Steel

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Lead screws full range

Lead Screw Accessories

Lead Screws Accessories
Lead Screws Accessories; Handwheels and positioning counters.

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Lead screws accessories range

Square steel nuts for lead screws - L1336

Square Steel Nuts - L1336
Steel square nuts for lead screws. Standard nuts are right hand thread, single starts.

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Square Nuts full range

Stainless steel nuts for lead screws - L1341

Cylindrical Stainless Nuts - L1341
Stainless steel nuts made for lead screws. Suited to withstand corrosive chemicals.

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Stainless nuts full range

Flanged self-lubricating plastic nut - L1342

Flanged Plastic Nuts - L1342
Flanged, Self-lubricating plastic nuts made for lead screws. Standard nuts are right hand thread.

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Plastic nuts full range

Flanged Ball Nuts - DIN 69051 - L1380
Steel flanged ball nuts to DIN 69051 form B. To be used with ball screws number L1385. Supplied with Vulkolan Seals.

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Ball Screws full range

Flanged Double Ball Nuts - L1381
Steel flanged double ball nuts. For use with ball screws number L1385. Supplied with Vulkolan Seals.

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Ball Screws full range

Centre Flanged Ball Nuts - L1382
Steel centre flanged ball nuts to DIN 69051 form B. For use with ball screws number L1385. Supplied with Vulkolan Seals.

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Ball Screws full range

Cylindrical Ball Nuts - L1383
Steel cylindrical ball nuts. For use with ball screws number L1385. Supplied with Vulkolan Seals.

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Ball Screws full range

Cylindrical Ball Nuts (with thread) - L1384
Cylindrical ball nuts with thread. Made in steel. Sizes from 16∅ to 25°

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Ball Screws full range

Ball Screws from sizes 16° to 80°
Steel rolled ball screws from sizes 16° to 80°. Available and in stock today.

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Supports full range

Fixed Supports for Ball Screws
Fixed supports available for ball screws and nuts. Available in a range of sizes and shapes.

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Supports full range

Floating Supports for Ball Screws
Floating supports available for ball screws and nuts. Available in a range of sizes and shapes.

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Ball Screws full range



Steel Lead Screws - L1320

Lead screws - steel from Automotion - we hold a huge range of stock of trapezoidal thread lead screws. From 10 mm diameter all the way up to 120 mm diameter. Stocked lengths are 1 metre, 1.5 metres, 2 metres and 3 metres. We can also machine the lead screws to customer's drawings. These are very competitively priced lead screws to DIN 103, ISO 2901 and ISO 2903. These are our standard right hand thread lead screws. In stock for same day dispatch.

Steel Lead Screws - L1321

Left hand thread lead screws - steel from Automotion - we hold a huge range of stock of trapezoidal thread lead screws. From 10 mm diameter all the way up to 120 mm diameter. Stocked lengths are 1 metre, 1.5 metres, 2 metres and 3 metres. We can also machine the lead screws to customer's drawings. These are very competitively priced lead screws to DIN 103, ISO 2901 and ISO 2903. These are our the less used LEFT hand thread lead screws, for right hand thread lead screws see L1320. In stock for same day dispatch.

Stainless Steel Lead Screws - L1322

Lead screws - stainless steel from Automotion - we hold the UK's largest range of stainless steel 316 (A4 stainless) trapezoidal thread lead screws. From 10 mm all the way up to 70 mm diameter. Stocked lengths are 1metre, 1.5 metres, 2 metres and 3 metres. We can also machine the lead screws to customer's drawings. These are very competitively priced lead screws to DIN 103, ISO 2901 and ISO 2903. These are our standard right hand thread lead screws. In stock for same day dispatch.

Stainless Steel Lead Screws - L1323

Left hand thread lead screws - stainless steel from Automotion - we hold the UK's largest range of stainless steel 316 (A4 stainless) trapezoidal thread lead screws. From 10 mm all the way up to 70 mm diameter. Stocked lengths are 1metre, 1.5 metres, 2 metres and 3 metres. We can also machine the lead screws to customer's drawings. These are very competitively priced lead screws to DIN 103, ISO 2901 and ISO 2903. These are the less used LEFT hand thread lead screws. In stock for same day dispatch.

Steel RH & LH Lead Screws

Steel lead screws with right hand and left hand thread on the same bar allows for bi-directional travel. Trapezoidal thread manufactured to DIN 103, sizes from 10x2 up to 32x6 with specials manufactured on request.

Cylindrical Bronze Nuts - L1330

Bronze cylindrical lead screws nuts for trapezoidal lead screws. The L1330 lead screw nuts are bronze cylindrical nuts - to suit lead screws from 10mm to 80mm diameter. Automotion stock a huge range of bronze cylindrical nuts - for same day dispatch. Use with our steel or stainless steel trapezoidal lead screws.

Flanged Bronze Nuts - L1331 + L1332

Bronze flanged lead screws nuts for trapezoidal lead screws. The L1331 lead screw nuts are bronze flanged nuts - to suit lead screws from 10mm to 70mm diameter. Automotion stock a huge range of bronze cylindrical nuts - for same day dispatch. Use with our steel or stainless steel trapezoidal lead screws. Flanged nuts have a larger, plain flange for your own fixing holes to be matched into.

Square Bronze Nut - L1334 + L1335

Bronze cylindrical lead screws nuts for trapezoidal lead screws. The L1330 lead screw nuts are bronze cylindrical nuts - to suit lead screws from 10mm to 80mm diameter. Automotion stock a huge range of bronze square lead screw nuts - for same day dispatch. Use with our steel or stainless steel trapezoidal lead screws. L1334 nuts have through holes for easy fixing. L1335 nuts are plain square nuts.

Hexagon Steel Nuts - L1338

Steel hexagonal lead screws nuts for trapezoidal lead screws - these are one of the least expensive lead screw nuts (it is best to use a bronze nut for most applications - unless the application is very low spec or the lead screw and nut can be regularly greased). The L1338 lead screw nuts are hexagonal nuts - to suit trapezoidal lead screws from 10mm to 70mm diameter. Automotion stock a huge range of steel hexagonal lead screw nuts - for same day dispatch. Use with our steel trapezoidal lead screws.

Cylindrical Steel Nuts - L1339 + L1340

Steel cylindrical lead screws nuts for trapezoidal lead screws - these are one of the least expensive lead screw nuts (it is best to use a bronze nut for most applications - unless the application is very low spec or the lead screw and nut can be regularly greased). The L1339 lead screw nuts are cylindrical nuts - to suit trapezoidal lead screws from 10mm to 70mm diameter. Automotion stock a huge range of steel cylindrical lead screw nuts - for same day dispatch. Use with our steel trapezoidal lead screws.

Precision Series - Rectangular Nut Lead Screws - L1347

High precision lead screws - stainless steel or aluminium. These L1347 lead screws are Automotion's range of high precision and often high lead, lead screws. The acetal resin nuts fits extremely well to the lead screw - with virtually no "play". These lead screws have rectangular nuts - for easy adaptation. From miniature lead screws of 4mm diameter with 1mm leas (ie the nut travels 1mm for each complete screw revolution) to 20mm diameter with 10 mm lead. Precision lead screws from stock at Automotion.

Precision Series - Round Nut Lead Screws - L1348

High precision lead screws - stainless steel or aluminium. These L1348 lead screws are Automotion's range of high precision and often high lead, lead screws. The acetal resin nuts fits extremely well to the lead screw - with virtually no "play". These lead screws have flanged cylindrical nuts. From miniature lead screws of 4mm diameter with 1mm leas (ie the nut travels 1mm for each complete screw revolution) to 20mm diameter with 10 mm lead. Precision lead screws from stock at Automotion.

High Precision Lead Screws - L1349

Stainless Steel High precision lead screws. These L1349 lead screws are part of Automotion's range of high precision and often high lead, lead screws. These lead screws have flanged cylindrical nuts.

Lead Screws - General Sizing Data

To select the correct size of lead screw and nut to use, please take into consideration the following three points:

  1. The size required to minimise the wear of the nut due to friction.
  2. The maximum load the screw can take before it bends.
  3. The maximum rpm the screw can run at before it begins to vibrate.

Finding a size to minimise the wear of a nut

Due to friction between the lead screw and nut, some of the power put into the lead screw is lost as heat. The solution is to limit the contact surface area between the lead screw and nut as this will help reduce the amount of friction and wear on the nut.

Lead screws are used to convert rotary motion into linear motion.

The efficiency of a lead screw and nut is defined as the amount of power you get from the nut in relation to the amount of power you put into the lead screw to begin with. For example, Pt (the power you put into the screw) divided by Pu (the power you get from the nut) = the efficiency.

The efficiency depends on the friction between the contact surfaces of the lead screw and nut, and the lead angle of the thread.

The speed the nut moves along the lead screw must also be taken into consideration in order to limit the amount of friction in the system.

Please see the formulae on the next page which help in calculating the speeds in your application.

Calculation of the contact surface pressure p

The contact surface pressure p is calculated using the following formula.

lead screws calculation of pressure

Calculating of the sliding speed Vst

The sliding speed is the result of the speed at which the nut moves and the friction. Calculating the sliding speed helps you to calculate the required rpm of a screw if you know what speed the nut must move at, or help to calculate how fast the nut will move if you know the rpm of the screw.

You must first find the sliding speed of your lead screw and nut using one of the below formulae and then use this to calculate either rpm or output speed of the nut.

he sliding speed is calculated using one of the following formulae.

lead screws calculation of sliding speed

lead screws calculation of sliding speed

lead screws calculation of sliding speed

Lead Screws - General Selection Criteria

The choice between different types of lead screws and lead screw nuts available is generally made after taking into account the following factors.


Choice of the Screw - Working Environment

For work environments where there are no particular corrosive or oxidising agents our steel (L1320 and L1321) lead screws can be used.

Where these conditions are not met, we recommend using our stainless steel screws (L1322 and L1323) which are particularly suitable in the following cases:

  • With a relative humidity of 70-80% and above.
  • Immersed in water (inculding sea water).
  • In the presence of particular corrosive agents such as chlorides. In the case of highly corrosive agents please contact out technical department.
  • In the food industry or pharmaceutical industry, where they are used with stainless steel or bronze nuts.
  • Where the lead screws cannot be reached for lubrication. In particular, for lubricating "maintenance free" fittings they are coupled with plastic nuts.
  • Where working temperatures are relativley high (above 200°C) - because stainless steel has a structure that is more suited to higher temperatures.

Choice of the Screw - Backdrive

Irreversibility defines how much the nut can "backdrive" down the lead screw. If a nut cannot backdrive down the screw then it is irreversible. This is especially important if the lead screw and nut being used in a vertical application i.e. in this situation no backdrive is normally acceptable.

Lead Screws with a lead angle of < 2° 30' are completely irreversible i.e. they cannot backdrive. Lead screws with a lead angle >5° but < 6° still have a good degree of irreversibility and may in some instances exhibit some backdrive.

Lead screws with a lead angle >6° have zero irreversibility, therefore the nut may backdrive down the lead screw with little or no load applied.

This is important to know in vertical applications.


Choice of the Nut - Working Environment

Our bronze and stainless steel 303 lead screw nuts, are resistant to standard oxidizing agents that occur in various applications.

Where corrosive agents are present, please contact our technical department for advice.

In applications where the presence of added lubricant (grease or oil) is not allowed we recomend the use of self-lubricating plastic nuts.

The use of plastics can however be limited by the specific working conditions, therefore please consult our technical department should you wish. This is because plastics have excellent self-lubrication features, but at the same time have restrictions on the working temperature or moisture absorption problems, (as well as some mechanical properties that may not be suitable for the intended use).

Lead Screws - Torque and Power

Torque

The torque necessary to move a screw and nut system is calculated from the following equation.


lead screws torque and power

The torque value however does not consider the efficiency of mechanical parts moving together with the screw system, such as bearings, belts or other transmission components. In a planning project phase, an increase between the 20% and 30% of the theoretical value is recommended. If electric motors with low static torque are used assume another increase of 50% to find nominal torque.

lead screws torque and power

Power

The power necessary to move a trapezoidal screw and nut system is calculated from the following equation.


lead screws torque and power

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