05-15-2016, 02:55 PM
I use a carbide drill and spotface.
Then, i use several hss taps with lots of moly lube. This takes time, if you rush it, the tap will fail. When the leading cutters on the tap start to roll over, chuck it in the trash and use a new one. Usually takes three new taps to do the job.
SG4247
Then, i use several hss taps with lots of moly lube. This takes time, if you rush it, the tap will fail. When the leading cutters on the tap start to roll over, chuck it in the trash and use a new one. Usually takes three new taps to do the job.
SG4247