historicalarms
Ultra Member
Im not sure my offering will work as you say the work is a big piece that mounting in a drill press is not do-able however it may be do-able with a mag drill.
I have done this a couple times & it does work. I have had to drill & tap a couple very hard receiver rings ( WW I over-hardening was common in a couple U.S manuf rifles, hard enough for a file to skate on). You can spot anneal what your drilling quite easily...cut the head off 2 or 3 ordinary framing nails and chuck one up in your drill, touch it to your work piece and let er buck ( no lube of any kind, just dry). Keep the pressure on as long as your nail lasts, it will turn red from heat but keep the end touching where you want to drill...quickly change nails when it wont hold integrity to the steel anymore...you want to make the spot your drilling red hot also, as hot and red as you can make it then cover the spot with a thick towel to slow the cooling down ( anneals the spot). I could drill those base holes with a common hardware drill and also easily tap without straining a small 6-40 tap.
I have done this a couple times & it does work. I have had to drill & tap a couple very hard receiver rings ( WW I over-hardening was common in a couple U.S manuf rifles, hard enough for a file to skate on). You can spot anneal what your drilling quite easily...cut the head off 2 or 3 ordinary framing nails and chuck one up in your drill, touch it to your work piece and let er buck ( no lube of any kind, just dry). Keep the pressure on as long as your nail lasts, it will turn red from heat but keep the end touching where you want to drill...quickly change nails when it wont hold integrity to the steel anymore...you want to make the spot your drilling red hot also, as hot and red as you can make it then cover the spot with a thick towel to slow the cooling down ( anneals the spot). I could drill those base holes with a common hardware drill and also easily tap without straining a small 6-40 tap.
