Monday, November 28, 2011

Splitting Stone...

Most stones we work with need shaping to fit a certain need. Most shaping we are able to do with a hammer if the stone is of a small scale and a cooperative material. But sometimes the stone is too large to manipulate into shape with a 3-4 pound hammer. At the point we need to shape thick material in length, we resort to 'feathers & wedges'(colloquialisms  vary), or sledge hammers sets with specific cutting heads. 

The process is simple:basic math, consistency, and pressure split the stone.
It has been done for centuries using the same methods. Centuries ago... holes were  drilled in a stone to a certain depth, spaced out at regular intervals, and dry wooden dowels were inserted followed by water being poured over them until they expanded and split the stone...
Today we have hammer drills and steel, and we speed things up a bit.
Cameron Scott of ExteriorScapes splitting Pennsylvania Blue Stone for a wall end that we built as a collaborative dry stone walling display at Marenakos.

 This is the face we all have after splitting stone.

 It really never ceases to amaze any mason or viewer of the process of splitting stone. 
The wall end coming up nicely with thick slabs of  Pennsylvania Blue Stone split using 'feathers & wedges', and smaller pieces of quartzite and limestone that is easily shaped using 3-4 pound hammers.

Here is what the 'feathers & wedges' look like set in the ready to get to work.
The 'feathers are the outside pieces that are shaped like an 'L'. This one here is 12" long and is laid out for splitting big blocks of high quality architectural/carving limestone at Continental Quarry. The wedges were attached to jack hammers...

The Process works well on most stones, and depths....

Sometimes I use it just for an interesting detail in relatively simple settings for a bit of contrast...
The marks left by the process always interest me because it adds more visually to the stones that reveal the story of the process.

Here is my daughter demonstrating the process on a piece of granite that I wanted to use for a 'through stone'... It took her 3 minutes of tapping them, but the granite eventually yielded to her persistence.

Many stone can be easily split using a couple of sledge hammers and specific faces. I love this process as it takes a bit more time, but it requires more of the body and mason reading the grain of the material.

Again the happy face... Forest with enthusiasm splitting a local schist
that we hand quarried for a client.

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