I used to work for a large awards company where we did a lot of drag engraving. You would need a holder that has an adjustable spring load, unless maybe your table is absolutely perfect. Even then, you may be drag engraving something like lacquered brass, where there may be slight differences in finish thickness, and without that "spring" you'll get inconsistent lines. The ones I used were all 1/8", but you might be able to sleeve them if your collet is 1/4". Also comes in diamond tip.