<p>If you could find out what model of machine the College Board uses to grade scantrons, you could fire off an e-mail to the manufacturer and they could probably tell you.</p>
<p>The thing I’d worry about with a .5 lead pencil is that the machine might pick up some answers but not others (because, say, one sensor is slightly less sensitive). Then you could get a terrible score, but the test wouldn’t be auto-cancelled.</p>