Hammerhead Stoneworks

A couple of weekends ago, I led a workshop at the NC Arboretum on building stone benches. First thing in the morning we studied images of various benches, stone-cutting techniques and ways to move heavy objects safely and with relative ease. Safety was a recurring theme throughout the day. After the classroom presentation, we went outside and built a free-standing bench, a style I call castle-block for the big chunks of stone that make up the supports. The bench we built is now a permanent fixture at the Arboretum, a rest station along one of the trails.

To facilitate ease of movement, we cut the big stone down in the back of my truck. In this image, Ronnie is using a star bit chisel to notch shallow guide holes in the top of the stone. This gives the drill bit a place to sit, reducing the likelihood of the bit bouncing around and scarring the stone.

Everyone got a chance to use the drill and work at cutting stone. Here Judy leans into the drill to get the proper placement.

Since our cut edges were going to be exposed, we took some time to clean up the drill holes. Here Carol is using a handset chisel to knock off the cut edge of the bench stone. We put the cut edge to the back of the bench, less visible to passers-by.

We spent some time doing bench math, designing everything so that it would be the proper height and balanced as a structure and as an aesthetic object. Here Carol measures the thickness of the slab, the starting point for figuring out the math. I handed out the following worksheet to guide the design and layout process.

By cutting it in the back of truck, we made the stone more manageable, but it was still a heavy chunk. Jason uses a rock bar to move the stone from the pallet onto the ramps we have set up. Using 2″ by 12″ pressured treated lumber as ramps, we slid the stone down to waiting blocks and from there into place.

We used mortar to set the bench. This design can be done dry, but the mortar reduces the risk of movement, particularly since the bench is in a public place.

We all felt good as we finished up. The bench looked great and we had built it efficiently and safely. It felt good to be leaving something cool and useful for everyone to enjoy. Tre and Ronnie test drive the bench and pronounce it good.

Click on the image above for the super sized version.

Here’s the scene at the entrance to the Rock Hill horse farm. The connecting wall will top out at about 28 inches, so there’s a bit more to go. The far column has some sample caps resting in place. Columns of this volume might require a massive cap to help visually anchor them. That decision hasn’t been made yet…

Here’s a front-on view of the mailbox vault shortly after completion. I’m very partial to this style: structural quoins, solid stone lintels, serious gravity. It’s a mix of old school and new style. My conservative estimate puts each column weighing over two tons.

This is a plan from my tiny notebook that I eventually scrapped, in favor of thinner stones for the quoins, adding an extra pair of stones in order to make full height. I worried that at almost 7″ thick, the quoins as drawn would be out of scale to the rest of the work.

Detail looking down the quoins.

This North Fence Lizard spent the night resting in a nook in one the block I used for my low scaffolding. It was a very safe place until I started work in the morning. I had to move him because he was too cold to move himself. His tail is obviously shortened, perhaps by a predator, perhaps by not being careful enough around the stone pile.