MerriwayBH06046 Whitworth Slotted Round Head Machine Screws with Nuts, 3/16 inch x 2.1/2-Bright, Pack of 20, Bright Zinc Plated, 3/16 x 2.1/2, Set of 20 Pieces

These are exactly what they say: Whitworth #10 bolts.My daughter picked up an old chest of drawers. Some of the knobs were loose and missing the bolt that holds them in from behind. I said I'd send her some from my miscellaneous bolt collection and took a bolt and knob home to find the right size. I have built up a large bolt collection over the years but did not have anything that quite matched. It was not metric and it was not a normal imperial thread.So I got my Vernier callipers out and found that the existing bolt had 24 threads per inch, and after some searching on the Internet I found a diameter match for this bolt size: an old Whitworth #10 with 24 threads per inch. A search on Amazon turned these up, so I ordered them.They fitted perfectly. The only problem was that I needed one inch bolts and these were 2.5 inches long. With a bit of effort with a hacksaw (the metal these are made of is quite hard!) and a rounding off on my grindstone and I had a set of 1" Whitworth bolts, which fitted the drawer knobs perfectly (see photo).