I lost my anchor due to missing instructions. I found it with A 7/16" drill bit and reaming the hole worked a little better. If you're using a hammer to drive the anchor in, use only very light taps. I found I had to remove the anchor and drill a hole. Hole for Sleeve length plus 1/16". I had to hold the bolt with my fingers until the bolt stopped turning and the anchor engaged. Generally everything worked as intended.