謝謝你的好主意。我總能從你的跟帖學到東西！難得！

就是有點貴。周末好！

$6.19 for 25 pieces in Amazon:

https://www.amazon.com/Stainless-Nylon-Insert-Lock-Nuts/dp/B00AGLOKHC/ref=asc_df_B00AGLOKHC/?tag=hyprod-20&linkCode=df0&hvadid=312061962710&hvpos=&hvnetw=g&hvrand=13411850476436457705&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9003318&hvtargid=pla-570344265744&psc=1

on ebay shipping from China (shipping in 14 days)：

$1.04 for 10 pieces with $1.99 shipping, black carbon steel, M3, 

https://www.ebay.com/itm/163599414886?hash=item261748f666:g:3mkAAOSw6GhcjJrw&amdata=enc%3AAQAIAAAA4PkvJuSxo%2BLhjRUAfj5T%2B0cKuUErvUqDCOgCEvdt1JRho6uxq6GT1%2BbiU4U8ILgIBm70R4OrsqHzuvBrF6Wh8Z8tITfaA0MYu1wo4TYkRWZt5rXGkj49iBvPKS4a1e1WQReqqOO3Xd9LnXhTbPP3LXsv3CuG26Crii59jI0gJtC1vx0hC7VKlVi4SXejpg%2B4AXL%2FrNekwhz1Ad3MDZTlE%2BjhI34MjR9hLUjD2u7kHXKPszXL4Z5On7YOJjBKtQpbCQEKxSdHs3uByfNyJZuw7YX0gjq443QZLI4Prtgj88ao%7Ctkp%3ABFBMnP6RyvRh