I've pulled the trigger some 15 times on my little bay gun, with both 2 and 3 band setups, and have been trying to pay close attention to the penetration I get. I'm using a crappy JBL slip double flopper slip tip at the moment, but one of my next projects will be to build my own. All of which got me to thinking about the way a shaft penetrates. Has anyone ever seen REAL testing to compare the penetration of different shaft diameters, and pencil vs. tricut tips?
I was thinking about setting up a little test fixture. Basically, a weighted pendulum with a few inches of shaft attached to the weight. Pull the pendulum back to a given height, and let it swing down against the target. I think that would give a pretty repeatable "input energy". Now, what to use for the target? I was thinking about using a stack of pieces cut from a scrap sheet of wallboard (drywall) because I can get all the scraps I want from the dumpster at a house under construction. It's a little softer, and hopefully more consistant in hardness, than wood.
Things I want to test:
1. For a given diameter (say 5/16"), which geometry penetrates better? (conical point, full tri-cut, conical with tri-cut point, or hollow ground point).
2. Compare the penetration of a 9/32" single flopper vs. 5/16" single flopper. I don't have either one, so maybe someone could donate the front 8-12" of a wrecked shaft?
3. What else would be good to know?
All input is greatly appreciated. I would really hate to get this all done only to find out that I overlooked something major. I'm sure this has been done, but I can't find it anywhere.