Hey Thomas:
Yes, this bad boy is stout, with the side plates being 1/2" thick! I bought my tips at the local Kubota dealer, who had several styles in stock.
Thanks for the tip about the crimping thing. I chose to weld these on because two of the shanks were badly worn. When the tips are worn on those shanks, it will be time to replace the shanks, and then all tips will be crimped as you suggested.
Once I got the tips on today, I found out why the grease fittings wouldn't take grease: the axle is totally rusted to the outside bearing retainer. I shot a can of WD40 on it, pounded like crazy (got about 90 degrees of motion on one, about 30 on the other. If I remove the two bolts on each retainer, I can flip the tool to engage the rippers, but this is not an acceptable method. Not entirely sure of how to proceed from here, except to keep putting penetrating oil on the thing and hope it eventually loosens up enough to pull it apart and clean it up (I seriously doubt that I will find replacement parts, so I have to make what I have work).
On the positive side, I just spent two hours cutting sharp edges off of ditch banks in dense silty clay. The Kubota had no trouble pulling this monster, and because of the extendable lower links, hitching up was a breeze! Just have to get the axle freed up, and it will be a wonderful addition to my implement collection.
Bob