Google 3" 10-24
Here is a link that might be useful: Here's 56 of them OR GOTO Home Depot
I did go to Home Depot and they didn't have any! I was shocked.
www.mcfeelys.com for wood screws.
Wood, sheet metal, exterior, structural, machine???
Fastenal probably either has them or can get them into their store.
I need them to replace too short pin head screws that go through the center of some ceramic cabinet knobs we bought. Our children love the decoration on the knobs, but they screws they came with are so short they don't go through the cabinets. They also have no place on the head for a screwdriver, but since I can't find any long enough that are plain heads I figured I'd have to resort to regular screws and just have it not be as nice looking, unfortunately.
Here's 56 different choices depending upon the material and head type you want
Edit: Oops, search does not come through on link. Put 10-24 in search box, do search, then drop down box on length to 3"
Here is a link that might be useful: Search results on Fastenal
This post was edited by bobsmyuncle on Sat, Jul 26, 14 at 17:36
I post the link two hours after you ask and then the same link is posted twice by the same person? lol
Well, first; Home Depot or Lowes probably did have them but they were probably in a long set of drawers of specialty hardware. I am actually surprised that they weren't right out on the rack. They are still common.
However, it sounds like you should be looking for some kind of thin long bolt, not a screw, because you would want to thread a nut on inside the door or drawer. They should be there too.
If you like the screws you have, but they are too short, perhaps you can counterbore the back of the hole to make them reach.