I don't own a middle buster tip, but only have a subsoiler tip on mine. I used mine behind a 100 hp tractor ripping up an area I was clearing. Unfortunately I hit a buried rock and snapped the tip right off. My subsoiler was made in the 40's and parts aren't exactly available. I bought a couple of replacement scarifiers for a box scraper and used 3 3/4 grade 8 bolts bolting one on. (I didn't want to weld it on just in case it didn't work right)
The first time out I twisted that scarifier into a pretzel. An old farmer by me told me to take my good one, heat it up a bit with a rosebud torch and dip it in used motor oil; repeat several cycles. Now make sure you don't get too hot and that you have someone close with a fire extinguisher in case you start the used motor oil on fire. I did a couple of times, but it was a weak fire and easy to put out. Anyway, after a few cycles of doing that I hardened the cheap tip to the point where it worked great. He told me that what I did was a poor mans version of making high carbon hardened steel out of mild steel. I dunno, but it did work. Good luck!
