Took apart and cleaned up this odd ball Geometric Head....on the hunt for chasers now.  The chasers in it are odd.  They say 18 18.  From what a can gather the head is adjustable so it can do 18 tpi on a range of sizes...5/16 the only one useful?

[video width="1920" height="1080" mp4="http://lincolnsmithy.com/wp-content/uploads/2017/06/VID_20170617_154803.mp4"][/video]