I had my own personal hero growing up. My grandfather turned 100 on Valentine's day. He served in North Africa, Sicily and Italy. He was in an artillery battalion with the biggest battle being Po Valley. Sadly the afternoon before his 100th birthday he fell, broke his hip and with...
I order Neodymium magnets, sometimes from Amazon, sometimes direct from China. They are indeed pre-drilled with a countersunk hole. Just checked, 15mm diameter, 3mm thick N52 magnets are running just under $3 for 10 from China. The more you order the cheaper they are. I usually order 50-100...