I have a couple dozen aluminum 20mm dogs, nicely machined from aluminum ... all brand new (never used). I had them machined because I wanted tighter fitting dogs and needed some custom lengths for holding my MFT square and other jigs I use on my MFT tops. Two lengths of 36mm and 61mm. The shorter dogs have a 1/4"-20 thread all the way through and the 61mm only about 1/2" in one end .. the other end is slightly rounded at the corners for easily inserting into the hole. I found knobs I purchase through Zoro (shown) have a 21.4mm shaft, so they work good for inserting the dogs and being able to pull the tighter fitting dogs out. I use Festool MFT tops and found that holes are not consistent, so all dogs fit tighter/looser in holes on the same top, these will be tighter than most. Will sell the shorter ones for $3 ea. and longer dogs for $3.50 ea .. plus $5 for shipping in the US. Message me if interested.