S e c t i o n 4 - P a g e 4 May 2013 Bit Selection - Button bits ar e commonly up to 2.5mm lar ger than their slated size. A 37mm button bit may in r eality be 39.5mm in diameter when new . This is too lar ge for an SS- 39 friction. Button bits do wear quickly however , incr easing anchorage capacity and incr easing drive times. Cr oss or “X” bits, on the other hand, a re sized true to stamped size usually within 0.03". They hold their gauge very well but tend to drill slower than button bits. They ar e pr eferable to button bits for friction installation wher e possible. Perpendicular Installation - Bolts should be installed as near perpendicular to the r ock surface as possible. This ensur es the welded ring is in contact with the plate all r ound. Bolts not perpendicular to the plate and r ock surface will r esult in the ring being loaded at a point which may cause early failur e. Unlike other r ock bolts, spherical seat washers ar e not available to corr ect for angularity with frictional stabilizers. Installation Driver T ools - Driver tools must transfer per cussive ener gy to the bolt during installing, not r otational ener gy . This is opposite to most other forms of gr ound support. The shank end of the driver must be the pr oper length to contact the drill piston in stopers and jacklegs (i.e. 4" long for 7 / 8 " hex drill steel). The shank end on the drivers is r ound so as to not engage the r otation of the drill. The driver tools must have the pr oper end shape to ft into the friction without binding and causing damage to bolt during installation. Education - Pr oper education of mining personnel and supervisors is mandatory . As manpower tur nover is r elatively fr equent in bolting cr ews, education must be continuous. An informed workfor ce will save money in the long run. Monitoring - Installation must be monitor ed to ensur e pr oper pr ocedur es and quality ar e maintained. Pull-test measur ements should be r outinely conducted on friction stabilizers to checkinitial anchorage values. Installation Quality Guidelines continued www .dsiundergr ound.com