Wish I could help with the size, but I don't have that info. IF you have a local Ace Hardware, there is a good chance you can walk in and find what you need - just take one of the old ones for comparison. Don't know if all Ace Hardware stores are alike, but my local Ace has a fantastic fastener section, including lots of metric stuff - generally mine is a lot better stocked than Loews or Home Depot where threaded fastener and all thread type products are concerned. YMMV, of course.