The raw material slabs are ready
We succeeded in cutting relatively uniform slabs of the six raw materials we are using. We used a cheap tile saw and wore out a diamond blade in the process, but we managed to get 5 or more slabs of each material type. Unfortunately, we only had a small nodule fragment for one the chert types, and some of the other slabs are more irregular than is ideal. Depending on our results, we may need to get some additional slabs cut.
Lynn and I have been working on the plans for the rig that will test the fracture-toughness of the materials. We have decided to use indirect percussion with a hardened steel pin punch that will be struck with ball bearing. We have done some proof of concept testing, but it is still difficult to estimate exactly how much energy it will take to fracture the slabs, but we can adjust the size of the ball bearing and height we drop it from. Based on this initial testing we are concerned that the slabs will split rather than having a hertzian cone fracture. That will not matter as long as we can get consist results within and between the rock types. We also have comparative data that have been reported elsewhere for similar stone, which we will use to assess of results. We have also done a proof of concept on the electromagnet release for the ball bearing, and we now have everything we need to build the device worked out. As a result, if we get the funding we will be able to start working on the drop rig right away.
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