Patent # 3574381, but very vague as to what it does and no reference to the square drive. Didn't measure the size of the drive, but looks to be 1/4". Photos when the server unloads......
DM&FS
This gave me the knowledge to tell a friend.
Boomer: Check the other post about the 1/4" drive gripper. I forgot I posted this one w/ no pix due to the server issues. The other post has links to photos and I'm having issues deleting this post... I hope you'll understand.....
DM&FS