I have done every single hammer and sear that I have ever made by hand drill as well, no press or mill. The only time I have had problems, is on older hammers, they don't anneal easily like the new ones do. I use an 8-32 set screw (much larger than most), and I know from experience how much to compensate for "walk" as I drill through to get it half decently centered. I also use MAPP gas, but only 1 torch, not two. :t When I originally started, I bought a lot of 6 hammers off of ebay, and used them to perfect my technique and placement. To me, the sears are much easier than the hammers. I quench in oil rather than water, couldn't tell ya if it makes a difference or not, its just how I learned to do it back in High School Metal Shop. :t Afterwards, is when the "FUN" begins.