Sometimes I have to do a lot of carving in metal. Of course, a large thread diameter will be difficult to make, but up to 5-6mm is quite realistic.I will not tell for very long, it's easier to see this on video, but I'll explain a little.
Cordless drill Metabo PowerMaxx 4.8 V. It has a very convenient reversal switch and a spindle lock.
3mm drill for hole preparation
Rough tap with a diameter of 4mm
Finishing tap with a diameter of 4mm
Drill diameter 6.5mm to prepare the hole before threading and chip removal.
The operation takes very little time, first we drill a hole with a diameter of 3 mm, then we do a few turns with a 6.5 mm drill, cut it with a fine tap, then a clean tap, then we remove the shavings, everything. :)