Are you refering to Hardness of FR4. If yes, hardness of bare laminate? "Pelkey, Glenn" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 07/25/01 06:10 AM Please respond to "TechNet E-Mail Forum."; Please respond to "Pelkey, Glenn" To: [log in to unmask] cc: Subject: [TN] Compression Strength Limit of FR-4 Hi friends, Here's one you don't get asked very often. What is the z-axis compression strength limit of FR-4? Not looking at Flexural Strength, unless you think there's a way of correlating the two. Thanks, Glenn