I bought 3 Jacobs chucks a while back,the price was right and I needed a larger one for the lathe.I had keys for two of them in my junk drawer,but the other has got me stumped! It's a Jacobs#14 Spiral Gear Chuck,0 to 1/2",Knurled outside ring,in great shape,mounted on a #2 arbor. Called Jacobs Co. tech info.The lady that answered said there wasn't a #14 listed in her computer.It's lots older than she was!Patented Sept.16,02,Jan.26,09,Jan.5,15,Feb.17,25.