Center-It Drill Press Block: Essential Fabrication Tool for Perfectly Centered Round Tubing Drilling, 5" x 4" Base, 1.75" Height, 2.5" V Measurement, 3.5" x 3" Bolt Holes Center-To-Center

Very well made, glad to have them in my tool collection

Look at the seller's photo of drilling a pipe. Imagine what would happen if the drill bit grabbed. The rotational force makes the part being drilled climb up the sides; jamming the drill bit further into the piece, and exacerbating the situation. That is what happened to me while drilling 3.5" aluminum round stock. Just a little grab sent it crashing. It broke the bit, and bent the spindle on the Delta drill press that's been with me for 40 years. What looked like a relatively inexpensive solution to my tooling needs, turned out costing me more in the long run.On It's Own - the device relies on gravity and the downward pressure of the drill press to hold the piece in place. If the pressure stops; i.e. you stop pressing; back out of the the hole; punch through a side; or you are going too easy and not pressing hard or steady enough, bad things may ensue. Using a hand to help hold the piece in place in most cases is a bad idea. Again, I refer to the seller's photo. Would you want your fingers anywhere near that while it's running? Since you should clamp the work down, buy a decent vice with prismatic jaws, or a "V" block with a clamping yoke instead of this.

works well on the drill press

I gave it 2 stars because it does center a round item as advertised, but there is no way to secure the item. Using a small drill bit, 1/8", in the drill press the round item could be held. A 1/4" drill bit pulled the item away.