There are no locking bolts in the Grizzly model table. There is a ball bearing that is pressed onto the table shaft. On mine, it isn't a tight fit and is easily removed with slight pressure. It isn't easy to hold the casting while pressing on the table shaft, but it is fairly easy to remove, once you remove the worm gear.
The screw in the bottom is used to adjust the spacing between the edge of the table and the casting. I tighten it until it barely moves, back off the screw about 1/8 turn and smack it with a brass hammer.
I have a 3" and a 4" and they work exactly the same, but the 3" is slightly tighter.
One note, there is a slight bit of space between the side of the table and the base casting, so if you plan on using the locking screw, center the table with the screw tight. It can make a thousandths or two difference.
Steve Fox