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Concept generation, detailed design, product test rigs, 3D CAD models in Solidworks or Inventor, 2D manufacturing drawings, analysis and calculations.  Contact us for further details.


Surface ship and submarine degaussing, DG system design, magnetic treatment, magnetic range design, fluxgate magnetometer design, see here.  Contact us here.



Twelvetrees Engineering can provide technical support for legacy fluxgate magnetometer systems, repairs and calibration.  We hold a stock of 3-axis fluxgate magnetometers that are available for rental, calibrated and ready for use.  See dedicated page here and contact us for further details.



Magnetic field strength of magnetos with a fixed horseshoe type magnet reduces with age.  We can re-magnetise the permanent magnet of an ageing but otherwise functional magneto without dissassembly.  The result will be a stronger brighter spark at lower RPM, greatly improving difficult starting and  generally improving performance without a full and costly rebuild/rewind assuming there are no other issues.  Contact us for further details.



Why not add one of our weathervanes to your motor house, garage, home or outbuilding, customised with a representation of your very own vintage car or almost anything else.  We can generate a unique silhouette using a photograph supplied by you.  Efficient function is carefully considered in the design and being manufactured in 316 stainless steel, commonly referred to as marine grade, they are highly corrosion resistant for a long trouble free life.  Supplied ready for easy final self-assembly, engineered to last. 

These are now handled by our sister company Longhouse Design Ltd.



Twelvetrees Engineering Ltd. was started in 2006 by Roger Twelvetrees to support his consultancy work in defence magnetics.  The company is based near to Grantham Lincolnshire, in the UK. 


Roger is a Chartered Electrical and Electronics Engineer and Fellow of the Institution of Engineering and Technology.  Before starting Twelvetrees Engineering he was at various stages in his career, Research Manager, Business Manager and Chief Engineer of a major electronics manufacturer.  As well as a broad understanding and experience of all manner of electrical and electronic systems, Roger's main expertise is in measurement and control of low level magnetic and electric fields for the purpose of warship signature management.  He has over 40 years experience in the field of fluxgate magnetometer design, and the design, development, installation and operation of open sea magnetic ranges, fixed treatment ranges, land ranges and model ranges. He has been responsible for design of and setting to work of on board degaussing systems and trials director for the magnetic treatment of naval submarines and surface ships.  Roger is also able to draw on a broad network of expert contacts, such as civil engineers and software engineers to assist on studies and projects where required.


In 2013 Roger was joined in the business by his son William, a Chartered Mechanical Engineer who graduated in 2002.  After graduation William gained experience in the packaging of rugged electronic systems for naval applications before in 2005 moving to work for a well known company supplying ancillaries to the offshore oil and gas industry.  Initially specialising in thermal insulation William worked on projects for the wet insulation of subsea structures and designed many custom insulation enclosures and covers, including some operated by ROV.  He also gained valuable experience with many of the company's other products such as cable and flowline protection, surface buoyancy and buoyancy clamps, eventually becoming Functional Excellence Champion for the Design Engineering function through which he was also involved in recruitment.  With a strength in concept generation and also a practical hands on ability he became a senior engineer in the new product development/innovation team before the opportunity to work independently arose.  William is proficient in the use of both the Solidworks and Inventor 3D CAD systems, packages for which Twelvetrees Engineering hold current licences.

Roger and William share an enthusiasm for vintage cars, both being competing members of the Vintage Sports Car Club.  This led latterly to a project to recreate a factory racing car built by Wolseley circa 1910 to 1912 to break distance records.  The car was built up using a 'heap' of period Wolseley 16/20 components and a series of original photographs for inspiration and guidance, the car being reverse engineered as closely as possible from the photographs.  Many parts of the car were 3D modelled to be sure that the finished article would be a fitting tribute to the original.  Some of the work involved is illustrated on this website.



For further information on anything you have seen please do not hesitate to get in touch or send us a message here.

Twelvetrees Engineering Ltd.

Bleak House




NG32 2BJ

07967 696567

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