Originally Posted by lajt

I did the same, but ordered them from McMaster Carr. The stainless steel screws came in a pack of 50 (35mm M3x0.5mm) for just $6.87, and a 10-pack of M3 acorn nuts for $4.68. The springs were a lot more, though, and I had to guess on the sizes like you said. I went with 15.5mm long, 4.6mm OD/3.4mm ID. That actually worked pretty well. Only problem was they were $4.60 per spring. The 35mm screw length turned out a bit too long, so I had to cut them with a Dremel, which thankfully didn't damage the threads at all. I think 30mm would be the perfect length.