The way I opened up my lower control arms (LCA) was to first scribe the outside diameter of the new UB sleeve onto the control arm in the correct location. I then used a new 3/16" diameter drill bit, I drilled many holes, very close to each other, all the way around the scribed hole. Of course the holes were drilled on the INSIDE of the scribed line. Then using a freshly sharpened chisel ,I set a block of wood in the area to be chiseled out (bottom of the control arm). The wooden block was used as a backup for when I chiseled through the small area between each drilled hole. NOTE: I did not distort the control arm at all using the chiseling method. This may sound very labor intensive, but it is really easy to do. Once the old pieces fell out I used a Dremel tool with a small cutoff wheel to carefully remove all of the remaining sharp pointed edges. I ground just up to the inside of my scribed lines, I could still see the line. At this point I started to trial fit the UB sleeve into the LCA. By looking closely, I was able to see the area that was keeping the new sleeve from tightly slipping into the control arm. I carefully ground out a small amount of metal until I could lightly slip fit the sleeve in place with a small ball peen hammer.
I worked with the tools I had available at home. I know there are easier ways to accomplish this job, but when the tools are not there you make do with what you have. Each control arm took slightly less than an hour to rework from start to finish (welding time not included in this time).