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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.

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.

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:

The size required to minimise the wear of the nut due to friction.
The maximum load the screw can take before it bends.
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.

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.

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

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:

Unless otherwise stated, grips on index plungers are not removeable.
Many of the pins on index plungers are toleranced to either the pin or the hole. Please refer to the specific product table.
Index plungers are not recommended for shear load applications.

	Pin Tol.	Hole Tol.
A	h_g	+0,03 +0,08
B	-0,02	h₇

S Stroke, or movement of plunger's ball or pin.
F₁ The Force required in Newtons (N) to over come the static strength of the spring and achieve initial movement of the plunger's ball or pin
F₂ The force required in Newtons (N) to fully compress the spring and to depress the ball or pin fully against the plunger's body

More technical info about spring plungers

FAQ

Can Wixroyd provide Index Plungers with a metal handle that has a semi-gloss finish in RAL 9017?

We currently do not provide this type of finish on our Index Plungers but if you have another handle specification for a special Index Plunger, please contact our sales team on 01483 266 777.

Can Wixroyd provide Index Plungers with a metal handle that has a semi-gloss finish in RAL 9017?

We currently do not provide this type of finish on our Index Plungers but if you have another handle specification for a special Index Plunger, please contact our sales team on 01483 266 777.

Can Wixroyd provide Index Plungers with a metal handle that has a semi-gloss finish in RAL 9017?

We currently do not provide this type of finish on our Index Plungers but if you have another handle specification for a special Index Plunger, please contact our sales team on 01483 266 777.

Can Wixroyd provide Index Plungers with a metal handle that has a semi-gloss finish in RAL 9017?

We currently do not provide this type of finish on our Index Plungers but if you have another handle specification for a special Index Plunger, please contact our sales team on 01483 266 777.