Based on these two questions:

I suspect that the answer will be no, but I want to ask anyway just to get it directly.

I hope to keep it more general than this, but for example:

There is a conceptual design for a loudspeaker that is easy to manipulate in a simulator and gives impressive theoretical performance...and is patented by someone else. The owner sells finished products exclusively to the very high end of the professional market (if you have to ask, you can't afford it), and hobbyists have built their own designs using that concept for their own living rooms, claiming that the owner has given blanket permission to hobbyists for their own personal use.

I've also seen someone with the owner's name on public hobby forums, who explains it in deep technical detail, and all of his posts are many years old now.


  1. Taking a cue from the hobbyists, what if an engineer/carpenter team were to design, build, and install one specifically for a non-profit organization where they both volunteer already?
    (the engineering and labor are donated, and the organization buys the materials)

  2. What if I were to design and build one myself to use in my own rig for profit?

My understanding of the purpose of patents is to prevent the loss of revenue caused by someone else undercutting the inventor, probably because the someone else doesn't have to make up the expense of inventing it. In that framework, and given either of the situations above, it would certainly be a violation to sell it, because that customer might have bought it from the owner instead if there wasn't a cheaper option.

But if the available budget clearly does not allow purchasing from the owner, and thus the owner would not have had a sale anyway (we'd use a different design that is available more cheaply), is it okay to make one (or several) personally or in-house for personal or in-house use, with the caveat that it is illegal to sell until the patent runs out?

Of course, we can't outsource the work because it would mean that they would be selling to us and thus violate the patent themselves. It seems to me that it must all be done in-house, to even have a chance. So does that chance exist?


It might seem like several different questions, but it's really the same question several different ways.

Nor am I asking if it's okay to violate in a particular situation. I'm asking if the action in that situation IS a violation.

  • The latter part of your question (starting "My understanding of the purpose of patents...") is basically a "fair use" argument (fairuse.stanford.edu/overview/fair-use/four-factors). However fair use only applies to copyrights, not patents. Commented Mar 1, 2020 at 15:39
  • 1
    As the answers to the questions you cite mention, MAKE and USE are things the patent owner gets to control. This misconception that only commercial exploration is relevant seems to be very deep. Commented Mar 1, 2020 at 17:44
  • Hobbyists can get away violating patents through a long standing common law exception allowing research of patented inventions: en.wikipedia.org/wiki/…
    – Ross Ridge
    Commented Mar 1, 2020 at 20:17

2 Answers 2


This is commercial use

Commercial is a lot broader than just for-profit and it encompasses not-for-profits if they engage in commercial activities at all. For example, a club charging membership dues is a commercial not-for-profit. A group of people with a common interest who take turns hosting meetings (e.g. a book club) is not commercial. It’s not a bright line, however, the use you are suggested would seem to be clearly commercial.

Notwithstanding, patent law doesn't care why you are breaching the patent. Even if this was non-commercial, it's still patent infringement.

  • The edit fixes this answer. However, it looks like a comment I left that inspired the edit has been removed. Am I mistaken that I posted a comment? Commented Jun 12, 2020 at 2:21
  • @GeorgeWhite no you posted it and I changed the answer then the comment was no longer needed
    – Dale M
    Commented Jun 12, 2020 at 4:14
  • Looking more closely, in my view, you removed some material and tacked on a short version of the right answer to the end of an otherwise wrong answer, including the title of the answer. Nate's answer was/is actually correct. If you deleted your answer the OP might pick his. Commented Jun 12, 2020 at 4:54

The relevant section of US patent law was already posted in an answer on one of the questions you linked, but I'll repeat it:

35 USC 271 (a): Except as otherwise provided in this title, whoever without authority makes, uses, offers to sell, or sells any patented invention, within the United States or imports into the United States any patented invention during the term of the patent therefor, infringes the patent.

Merely making a patented invention is infringement; it isn't relevant whether you sell it. It is also infringement if you use it yourself, regardless of who made it or whether you paid them, or whether you would have otherwise bought it from the patent holder.

There are some special exceptions for things like certain kinds of pharmaceuticals, but I browsed the rest of 35 USC Chapter 28, and didn't see anything that would appear to be relevant in this case.

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