</font><font color="blue" class="small">( I am always building with rock but never thought of fastening them. I am interested in a little more of the details like what type of drill bit, and is the dowl just rebar? )</font>
My first choice in dowel material is stainless, no rust. /forums/images/graemlins/grin.gif
I do quite a bit of work involving placing fence etc on concrete. So over time I've picked up a drill and trick or two. I've figured out there is nothing on gawd's green earth to compare with Hilti for drilling in rock and or concrete. Well, except for a checkbook of course. /forums/images/graemlins/smirk.gif
I've got bits from three sixteenths up to five inches for the Hiltis. They're masonary of course and work either with a hammer feature or without it.
What is challenging and fun about using the dowel principle is trying to make a hidden attachment that is mechanically sound.
You take the big slab table for instance. One of the challenges is when a drill goes through the other side it's not unlike what happens when a fool uses a hollow point on game. So I first went through with a half inch bit, the same size as the pilot pit on the two and a half inch bit. When I got to where I figured I was was within a half inch or so of the other side I changed from hammer to just drill. I still had a blow out but it was only about the size of a quarter.
This allowed me to drill down a little over half way with the two and a half inch bit from one side and then do the rest of the hole from the other side.
One of the problems with stone and cement is vibration is it's worst enemy. I had alread drilled a two and a half inch hole in the pedestal stone about six inches deep. But if I just put the top on over the pedestal, lined up the holes, and then filled it with Quick Rok there would be no safety factor if a fracture occured. I would in fact have nothing much more secure than just placing the slab over the pedestal.
I put a piece of two and three eighths pipe about eight inches inside the matched holes. Then I filled the cavity with Quick Rok. The piece of pipe is the safety factor. Even if the Quick Rok fractures across the joint the pipe will maintain it's integrity.
A good source of materials for working with rock this way is a granite countertop equipment supply shop. They carry a two part epoxy that'll enable you to take a trip without leaving the farm if mix it in an unventilated area. Stuff is mean. But they use it to join granite and it works.
They also carry grinding stones of varying degrees of grit. They're reasonable and fit you standard five eighths shaft angle grinder. These are invaluable when fitting stones. You can grind it down with a coarse and then polish away your grinding marks with a fine.
Sorta funny how it's all similar but different, steel, stone, and wood, when it comes to techniques. Of course with stone you never get that fit you can with steel or good hardwood. It's either a little sloppy or a little tight. And forcing it when tight most often introduces you to disaster and disappointment. /forums/images/graemlins/crazy.gif
One of these days someone's going to have the money to give me the time to make a project I've wanted to do for years.
I'd like to forge a tree out of iron. And where there would be a cluster of leaves I'd like to have stone. The stone would have hollows for moss roses etc.
I think it'd be just plain old pretty.
I'm also working on doing a rock rocker. /forums/images/graemlins/grin.gif That'd be too kewel for words.