The screws on my Stauff clamps which I use with the 60mm diameter elements on 40 are 12mm diameter (almost 1/2"). 73 Peter, DJ7WW -----Original Message----- From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Jim Thomson Sent: Sonntag, 12. März 2017 00:13 ### Typ stauff clamps that are all the rage these days use .25-20 SS bolts.