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Fastener Loads for Plywood - Screws <br />CITY OF SANTA ANA <br />Planning and Building Agency <br />Withdrawal: <br />Tables 3 and 4 present average <br />ultimate withdrawal loads for <br />wood and sheet metal screws in <br />plywood -and -metal joints, based <br />on analysis of test results. Wood <br />screws are threaded for only <br />2/3 of their length. Sheet metal <br />screws typically have higher <br />ultimate load than wood screws <br />in the smaller gages because of <br />their full-length thread. <br />Values shown in Table 3 for <br />wood screws are based on 1/4- <br />inch protrusion of the wood <br />screw from the back of the panel. <br />This was to assure measurable <br />length of thread embedment in <br />the wood, since the tip of the <br />tapered wood screw may be <br />smaller than the pilot hole. This <br />was not a factor for sheet metal <br />screws due to their uniform <br />shank diameters. <br />Approved <br />FOR PERMIT ISSUANCE <br />TABLE 3 <br />WOOD AND SHEET METAL SCREWS: METAL -TO -PLYWOOD �Ib�Nci°'' <br />Depth of Average Ultimate Withdrawal Lo <br />( f� <br />Threaded <br />Penetration Screw Size <br />(inch) #6 #8 #10 #12 <br />#14 #16 <br />3/8 150 180 205 <br />- <br />1/2 200 240 275 315 <br />350 - <br />5/8 250 295 345 <br />440 - <br />3/4 300 355 415 470 <br />525 - <br />1 - - - 625 <br />700 775 <br />1-1/8 - - - 705 <br />790 875 <br />2-1/4 - - - - <br />1580 - <br />(a) Plywood was C-D grade with exterior glue (all plies Group 1). <br />(b) Values are not design values. <br />lows <br />a <br />Wood Screy, <br />1_ <br />4 <br />Sheet Metal Screw <br />TABLE 4 <br />SHEET METAL SCREWS: PLYWOOD -TO -METAL CONNECTIONSM <br />Average Ultimate Withdrawal Load (Ibf)ibi <br />Plywood <br />Screw Size <br />Performance <br />1/4"-20 Self <br />Framing Category <br />#8 <br />#10 #12 <br />#14 <br />Tapping Screw <br />0.080-inch 1 /4 <br />130 <br />150 170 <br />180 <br />220 <br />Aluminum 1/2 <br />350 <br />470 500 <br />520 <br />500 <br />3/4 <br />660 <br />680 790 <br />850* <br />790* <br />0.078-inch 1/4 130 150 170 180 220 <br />Galvanized 1/2 350 470 500 520 500 <br />Steel (14 gage) 3/4 660 680 800 900 850 <br />(a) Plywood was A-C EXT (all plies Group 1). <br />(b) Values are not design values. Loads denoted by an asterisk(*) were limited by screw -to -metal - <br />framing strength; others were limited by plywood strength. <br />Form No. E830E ■ © 2011 APA— The Engineered Wood Association 0 www.apawood.org <br />