there is a thread ( cannot off hand remember where) on tbn and to give the author credit he made a very good point, keep in mind you are not trying to compete with a full size backhoe but are trying to be more cost effective than day labor, I built a towable backhoe several years ago, bronze bushings, etc, etc, after I completed my project (about 10 hrs of work) the machine sat for several years without use, I never loaned it out due to liability issues, and made the purchaser sign a waiver, now my .02 cents save your money on bushings/grease joints,and snazzy/complicated torch/plasma cutout parts, invest that money in good hydraulic components, my recommendation is to weld grade 8 or harder washers at the pivot points, use grade 5 bolts and check them for wear, my friend did this, bolts show no appreciable wear after 100 hrs of use, use common channel to make your bucket, look at lackender backhoes to eliminate the linkage at the bucket Ie: less pivot points/less things to wear out, I would not fool with making a curved main arm either the added benefits far out way the aggravation of getting everything lined up correctly and straight when assembled, unless you have access to a machine shop with wood fixtures, unfortunately I have always leaned towards functionability compared to cosmetically appealing, check with surplus centers for quality hydraulic products, keep it simple,an if in doubt build it stout,