thanks for the comments. i was making the holes larger to accomodate the hex head bolts, since the hardware store only stocks them down to so small a size... it slipped down too much is what happened, the collet made contact with the surface and marred it, not like a walking bit. in this case i don't think tape would have saved it, it probably would have just gone right through it. i would love a drill press, but i am really tight on funds right now and no way i can afford to buy one. i am also not using the best drill for the job, but its what i have access to. its a milwaukee high rpm high torque drill. i think its more meant for drilling masonry and the like... i always have to be careful not to press the trigger in too far or bad things happen, like it knocking over the whole workbench.