Jigs & Fixtures

At Presto we are constantly looking for ways to increase efficiency and streamline the manufacturing of aluminium precision machined parts.  The design of jigs and fixtures can have a significant impact on component quality and productivity.  Achieving the optimum design  is well worth the investment of a little extra time and care.

Jigs and fixtures  produce interchangeable and identical components.  They are unique tool guiding and work-holding devices designed specifically for machining and assembling large numbers of components.

In straightforward terms, jigs guide the tool and fixtures hold the work-piece in position but for the sake of clarity:-

  • A jig is a work-holding device that supports, holds and locates the work-piece and guides the cutting tool. Its main objective is to ensure a high degree of precision and repeatability in component manufacturing.
  • A fixture is a work-holding device that holds supports and locates the work-piece for a specific operation but does not guide the cutting tool. A fixture’s primary purpose is to create a secure mounting point for a work-piece.

Design Considerations/Principles for Jigs and Fixtures

At Presto we design and make Jigs and Fixtures for most of our CNC machining work. To ensure that we produce the highest quality aluminium components there are a number of issues we take into account :-

Locating Points

The position of the work-piece needs to be accurate with respect to tool guiding in the jig or setting elements in the fixture.  The aim is to minimise the time taken to insert and remove the work-piece into position.

Clamping Device

The clamping device should be as simple as possible without sacrificing effectiveness.  The strength of the clamp needs to be sufficient to hold the work-piece firmly in place and take the loads of the cutting tool.  This must be achieved without causing stress which can result in damage, marking or distortion to the component.

Fool Proof

Ensure work-piece and tool can only be inserted in the correct position.

Reduction of Idle Time

The design  needs to facilitate the loading, clamping and unloading time of the work-piece to  achieve  the minimum time possible


Keeping the weight  to the minimum without sacrificing rigidity will make them easier to use.


In some case the addition of handles can also enhance ease of movement

Advantages of quality jigs and fixtures

Investing time in ensuring that jigs and fixtures are of the highest quality is well worth the effort as it will impact the quality of parts produced.  Below are some of the advantages of superior jigs and fixtures:-


Good jigs and fixtures will reduce variability of dimensions of components and high volumes of parts can be manufactured of a consistent quality.


Allows multiple parts to be held and machined together.


The increase in productivity and reduction of scrap will contribute to producing the most cost effective high quality precision machined components.

Investing time and effort into producing high quality jigs and fixtures which are thoroughly tested will pay dividends.  For manufacturers of aluminium precision machined parts like us at Presto, this level of diligence is an integral part of our production process.  Our goal is to provide our customers with high quality aluminium machined components at a competitive price and investing in good jigs and fixtures is a significant contributing factor.

If you would like further information on jigs and fixtures or any other topic relating to CNC milling of aluminium machined components please let us know at sales@prestoeng.co.uk.

For more information about Presto Engineering please visit our website here and if you would like a quote or to discuss a project with us please call us on 01865 883508 or e mail Julian at sales@prestoeng.co.uk.