Straight shanks are now mainly rolled. The production process is, punching - centerless grinding - chamfering - four-stick mill rolling - quenching - tempering - cleaning - sandblasting - cutting tip - fine grinding - marking - oxygen desalination. Taper shank twist drills are divided into less than 20 rolled, extruded and milled. Process: sawing - welding - turning cylindrical - shank - milling groove - milling back - quenching - sandblasting and other very tedious.
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