Well, now that you ask, I have 50 extra ones. Yes, the right size for Steinway key blocks, not the slightly oversize ones that Pianotek carried for a short while. They are zinc-plated, and so more silvery that the plain steel ones, but that's the best I could find. Here's how I came by them:
We have a major supplier of fasteners, tools, etc., here in the Seattle area called Tacoma Screw Products. I have asked a number of times about these #18 x 2-3/4 FHWS with negative results. But one time a particularly enthusiastic salesperson took my request and called around to his suppliers. He found some from one of their suppliers (in New York City, maybe?) and got me a box. I was amused that he worried that the cost of an entire box of 100 might put me off. Wanted payment up front for a special order. But I pointed out that I mostly work on pianos that are valued at anywhere from $20000 to $200000, so a few dozen dollars wasn't going to be an issue.
So I have these 50 that I'm willing to part with. Cost is probably mostly shipping and handling. I think the screws will have to be in a box, as the heads are too wide for a padded envelope? I'm open to suggestions. Or you can have some fun with your local screw supplier (or even contact Tacoma Screw).
Doug