Who owns the drawings when you reverse engineer a part?
Two different questions get muddled together here, and only one of them is really about the law. This is what to ask, and where to stop and take proper advice.
The easy question: who owns the drawing we paid for?
You should. If you commission a drawing package, the deliverable is yours — the drawings, the CAD model, and the right to take all of it to any manufacturer you choose, including one that is not the firm who produced it. Anything less makes the drawing worthless as documentation, because the whole point of writing something down is that it stops being dependent on one supplier.
This is worth checking rather than assuming. Under English law, in the absence of an agreement saying otherwise, copyright in a commissioned work generally sits with the person who created it, not the person who paid for it. That is the opposite of what most buyers expect. So the position should be written into the engagement, in a sentence, before the work starts. If a supplier is reluctant to put it in writing, you have learned something useful about how a repeat order in three years will go.
Who owns the copyright in the drawings and models produced? Will I receive the native CAD as well as a PDF? Am I free to have the part made elsewhere using them? Will you keep an archive copy, and for how long?
The harder question: are we allowed to copy this part at all?
This is the one people actually worry about, usually somewhere around the second phone call, and it is not a question an engineering firm should answer with confidence. What we can do is set out the shape of it, so you know whether you have a problem worth paying a solicitor to look at.
Start by separating two situations that feel similar and are not:
- Maintaining your own plant. You own a machine, a component has failed, and you need another one so the machine keeps working. This is ordinary industrial maintenance and it is what the overwhelming majority of reverse engineering enquiries are.
- Making parts to sell. You intend to produce components as a product — for resale, for other people's machines, or as an alternative to someone else's catalogue item. This is a commercial activity competing with the original manufacturer, and it deserves proper legal advice before you start.
What UK design law actually says about fitting parts
UK unregistered design right is narrower than people assume, and the exclusions matter for engineering components. Section 213(3) of the Copyright, Designs and Patents Act 1988 provides that design right does not subsist in a method or principle of construction, nor in features of shape or configuration which enable the article to be connected to, or placed in, around or against, another article so that either article may perform its function. That is the provision usually called the “must fit” exclusion.
The same subsection also excludes features dependent on the appearance of another article of which the article is intended to form an integral part — the “must match” exclusion — and surface decoration.
In practical terms, the interface geometry of a mechanical part — the spigot that locates it, the bolt pattern that fixes it, the bore that takes the shaft — is the part of the design least likely to attract protection, precisely because it has to be that shape to work. This is not an accident; the exclusions exist so that design law does not become a monopoly over spare parts.
There is separately a repair defence for registered designs, at section 7A(5) of the Registered Designs Act 1949, covering the use of a component part to repair a complex product so as to restore its original appearance. It is applied narrowly, and it is about appearance rather than function.
Where this stops being an engineering question
Design right is not the only thing that can apply. A component may be covered by a patent, which is a different regime entirely and is not disposed of by any of the above. It may carry a trade mark or a distinctive get-up. It may be supplied under a contract or a licence that says something about spares. Software, firmware and anything with a control system raise questions that have nothing to do with the shape of the part.
So the honest position is this. If you are making a fitting component to keep equipment you own in service, you are in the territory the law most clearly accommodates. If you are making parts to sell, or the part is obviously the manufacturer's commercial product rather than an incidental component of your machine, stop and take advice from an intellectual property solicitor. That advice will cost you a fraction of what the argument would.
This is a description of the landscape by engineers, to help you work out whether you need a solicitor. It is not legal advice and it is not a substitute for it. Legislation is quoted as it stood at the date of writing.
What we do about it in practice
We raise it at the enquiry stage rather than at the invoice stage. If a job looks like straightforward maintenance of your own equipment, we say so and get on with it. If it looks like a product rather than a part, we say that too, and we would rather lose the order than find out later that nobody asked. It is not a comfortable conversation to have on a first call, and it is considerably less uncomfortable than the alternative.