Bearing blocks or “sockets” are a necessary element of the bow and spindle fire method. Over the years I’ve used a variety of items (see Bow And Spindle Bearing Blocks). The desirable qualities of a bearing block is that it is durable, easy to hold, and doesn’t transfer heat to your hand. Although I have used man-made materials for this purpose I wanted to explore making one out of natural materials.
I decided to use a clam shell because of it’s concave shape and hard surface but I felt that it needed support because of it’s thin wall so I went down to the creek to find some clay material to surround it. After kneading the clay I applied about a half inch layer across the backside and along it’s sides so that the finished product looked like I had pressed the shell into a ball of clay.
I let it dry for a week and the results were great! I noticed that the clay had receded slightly around the outside edge of the shell but remained whole without cracks. I applied the new bearing block to the test and it worked wonderfully. After a successful coal was formed I examined the bearing block and noticed a discoloration at the pivot point which is to be expected and some small fractures, so it will be interesting to see the length of service that it will give me. I also noticed that the exposed edge chipped down slightly to the top surface of the surrounding clay leaving a flush clean edge. It was easy to handle and feel that it was a great success.
This bearing block is simple to make and would make a nice addition to your collection of firecraft tools.