I’ve been with Steinway & Sons all my life. I started nearly 37 years ago as an apprentice at the factory in Hamburg, manufacturing pianos. Now I’m a concert technician, working with artists and venues to ensure that they have the right instrument in the best possible condition. I know pretty much every concert grand in the UK and Ireland, and there are a number of A-list pianists who want me with them wherever they play.

I do my job the same way as it was done a hundred years ago. There’s no computer involved. I tune the piano completely by ear, using a tuning fork to get the pitch. My tool kit is huge, but this particular tool, the toning needle holder, I’ve had for 35 years—it was given to me as an apprentice for getting good results in my exams. 

It’s essentially just a...