Thanks guys, I really appreciate the positive feedback!!! That slab of wood is one section of the trunk of a huge Ash tree that died in my backyard about 11 yrs ago. I cut the tree down with the intention of bringing the wood to a sawmill and having it cut into boards. The slab weighs 150 lbs and is quartersawn http://www.google.com/search?client=saf ... 8&oe=UTF-8
Finally decided to put it to use as is! (Part of a resolution to pull together everything bicycle into one room.) I clamped a fence onto the wood- a piece of a 2x4- and used a plunge router with a bowl bit to cut the slots.
Here are a couple of pics that show dimensions:
Nothing ventured, nothing gained.