prechambers mods?
prechambers mods?
HSS cr 0.7 drill bits , makes wonders . i use the brand BERNER germany . buy some 3 or 4. one lasts only one hole, then Sharp it do another one. in one hour is possible to drill all of them .
the best device is the electric screw driver( or the hell it is called in english) in high speed leave only 5mm of drill bit ouside, like that u can spare the bits.
i did 3 mm and 2mm at center. i did not tried them yet.
bonne chance.
PS: drill at dry conditions.