Note that the largest step bit size in this collection is 3/4" - but don't let that stop you from adding this cheap and effective set to your toolbox. I bought an expensive silver and deming bit set for enlarging holes, which still have their uses at times, but this set is far more effective when going through sheet metal or even plate (I drilled holes in 3/16" and 1/4" mild steel with these bits). They are effective cutters and very efficient. The long / multiple step bit is my most frequently used one as it goes from 1/8" to 1/2", stepping up at a reasonable speed. I'd still drill a pilot hole if going into thicker material though.