I have one too. It's an Abrasive Model 3B, 8x24" mechanical automatic surface grinder.
The manual can be ound free for download at Vintagemachinery.com... the trick is to look under "Landis" rather than Abrasive Machine Tool Co.
Landis bought the Abrasive grinder line and continued selling them without modification for a while, and this machine was simply the Landis 3B surface grinder for a while.
I've found it to be a very solid workhorse grinder... I modified mine to run 2x72" belts and use it a ton for flattening and truing billets in my damascus steel work and for other knife related tasks.