I would be surprised if the Embassy didn’t have maintenance staff to look after the building but why they would need a sander is not obvious, and then that much use to wear it out? Perhaps they might tell you what it’s used to make? It’s a puzzle why they didn’t just scrap it and get a replacement one too. There are authorised repair centres too (
http://www.jettools.com/us/en/p/10-20-plus-benchtop-sander/628900 , bottom of the page) so why wouldn’t a Government body use one?
Being quite cynical I wonder whether your mod will just be fed back to some company who will reverse engineer and patent it - wonder why they haven’t done it earlier. Intellectual property has a value, in law, and infringements can be expensive. That’s a trivial and laughable thought really, but so much in life is one or both of those and Embassies are there to look after their country’s interests. That’s just a thought, I’m not very trusting. Perhaps you might be better off returning their kit as received?