This is a blog on how to mount a sculpture to a wood or stone base when the tap holes are hidden. There is a trick to knowing where to drill the mounting holes so that they line up. I will show this step by step, with photos. The two key parts are covering the base in masking tape and scraping pencil lead onto the threads of the bolt holes. When the sculpture is then placed on the masking tape covered base, and beat lightly with a hammer, the graphite falls out of the bolt holes onto the masking tape, showing where one must drill the base so that the holes match up. See the tools sitting on the masking tape covered base below:

Below we see the bottom of the sculpture showing the bolt holes, the pencils, and, in the background, the base.

The key is scraping off some graphite into the bolt holes that had been welded onto the bottom for mounting, as shown below. The threads are great for scraping.

The next step is tapping the sculpture with a rubber mallet so that some of the graphite falls onto the masking tape.

Below, I have removed the sculpture from the base, seen where the graphite landed, and emphasized it with a sharpie.

Below, I have drilled three holes, one for each bolt hole. You will need a tungsten carbide drill, or similar, if you are drilling stone. Wear protective eyewear. Losing your sight is not good for visual artists.

Here I turned the base over and drilled large set-back holes for the washers and bolts. The drill press was set up so that I didn’t go in too deep.

Finishing up by screwing the bolts through the holes in the base and into the bolt holes in the sculpture.

In this case, the sculpture was a bas relief and needed to be attached to the wall. Since it weighs about 80 lbs, care was requried. The final step will be attaching the sculpture to a wall using an 18″ wide French cleat screwed to the studs which are usually 16″ apart.