Well....it's May now and I am still busier than a one legged man in an a$$ kicking contest. But to take a mental holiday, I spent a few afternoons back working on the cannon rebuild. I started by disassembling the cheeks from the trail. Each cheek is 3 inches thick and about 34 inches long. Made of solid oak, they are fairly heavy. Once off the trail, I wanted to complete the last drilling that was needed to install the "D" rings that hold the handspikes in place on each side. The cheeks were too big to set up on my drill press, so I drilled a 3/4" thick piece of aluminum with two 3/8" holes spaced correctly for the "D" ring to act as a drill guide. I positioned the guide in place and clamped it to the cheek. The guide made sure the hand drilled holes were properly spaced and perpendicular to the cheek surface.
However, then I realized that I was not yet done drilling holes. I had not mounted the retaining "eye pins" and chains that would retain my version of the cap square and key retainers. In my case, the chains would keep the brass cross pins from being lost if they managed to work free during transport. Here the eye pins and chains are mounted in the additional holes that had to be drilled.....
Also shown are the hand spike retained by the "D" ring forward and by the handspike washer hook aft.....
Between the cheeks and the forward end of the trail are three giant washers / spacers called "rondells". They hold the cheeks in the proper spacing for the width of the barrel at the trunions. Traditionally, they were made of cast iron. When I built the cannon as a high school student 50 plus years ago I just used 1" thick disks of aluminum and drilled them in the lathe with a 1/2" center hole to allow for the passage of the long bolts that held the cheeks in place. What I didn't know at the time was that the front two rondells are really just spacers, but the rearmost one had MUCH larger protrusions port & starboard (i.e. on either side). As the cannon is fired and recoils, the trunions transfer the recoil energy to the cheeks and the cheeks transfer it to the trail. The protrusion on the rearmost rondell were there to distribute that recoil energy over a much larger area and keep a heavy charge from damaging (splitting) the trail. Sort of like the difference between hitting a log on the end grain with an axe blade or a baseball bat.
Although I had never had a problem even with a full charge (i.e. a 3 1/2 pound ball and a full pound of powder) I thought I would remake the rear rondells more like they were supposed to be. I bored two of them in the lathe to an inside diameter of 1 3/4" and shrunk fit two 1 3/4" diameter center pieces to take the recoil shock. These are the original rondells.....
And here are the two rear ones modified with the much larger center pieces......
This view shows the side of the trail where the rondells are mounted between the cheek and the trail.
The next problem was how to bore the larger holes required for the modified rondells on center with the original 1/2" through holes. Without a center most drilling methods would have a problem maintaining a concentric bore. I thought of plugging the through hole with an oak dowel and then using a spade bit to drill the larger bore. But in rooting around in all of my various drilling tools, I stumbled on a 1 3/4" Forstner bit. It still needed a center.....or did it ? I ended up drilling a 1" thick piece of hardwood with the bit and then making a centering tool that would hold the drilled hardwood square concentric with the 1/2" through hole while I screwed it to the cheek. The the bit was held concentric by its outer rim rather than by its center point while boring out the larger diameter. The trick worked fine on both cheeks.....now I just have to drill the rear through holes on the trail to match.
