A couple of years ago, Jeff made me a tool to cut the slots in sponge holders. It did the job but it wasn't always great. We started to talk about what would create a straighter cut and work efficiently. Jeff came up with a mitre box design. This is his prototype, which is working quite well. I am sure it's going to get some tweaking along the way.
Using the back side of the saw makes a cleaner cut in the clay. We need to find a smaller blade that won't be so cumbersome to work with on my bench.
I cut across the bottom with a fettling knife.
After all the cuts are made I go back and clean up the edges. I also give them the green kitchen scrubby treatment before they go into the bisque firing.
Now if we can only solve the warping problem...