BioMax
+1y
I use 2" long F9-11 bolts for 3 reasons
1. They have a taller head and can be notched deeper if needed
2. The 2" thread is quite long and willallow extra adjustment if needed (I do believe that the 2 1/2" long bolts are completely threaded as well, but only use those occasionally.)
3. I can get them locally any time
You do not need to address them in any special way. If it is cold out, warm the parts up to at least 90deg or more and DO NOT quench them when you are finished welding. Make sure to use 1010, 1020, or 4130 DOM when making the bushing end, .120 to .250 wall depending on your needs. And clean off the dark grey outer coating wherever you are going to weld.
You don't need to use washers if you don't want to, I quite often don't, but if it a highly stressed part like a link bar on an off-road truck, I will use either AN bolts or grade 8 bolts long enough so that the "grip-length" (the unthreaded portion of the bolt) goes completely through the part and the tabs, so that there is no threads within the part. And whenever possible use nyloc nuts, not lockwashers.