53 "ALCHEMY" by Jensen Knives
53: Now that I no longer need the holes in the tang as guidance holes, I can tap them. I am going to hand tap the holes with a tap wrench using a 440-thread size tap.
Using a hand tap with a 440 tap to thread the previously drilled holes. Tapping involves patience above all things. In order to cut threads into the sides of drilled holes, taps have to be extremely hard; as such they are extremely brittle and are prone to breakage. Use new, sharp taps with cutting fluid. Carefully, and constantly checking for straightness, gently insert the tip of the tap into the hole, and with a little pressure give it a little clockwise twist to get it started. This is the only time you should use a little pressure, once you feel it bite, let the tap do the rest of the work. Using small 1/8-1/4 turns, twist the tap farther into the hole, back it out, then repeat just a little past where you had previously gotten. You will be able to feel when you are biting into fresh material. If you hear a loud squeak, immediately stop, and reverse the tap!! It’s better to take a half an hour per hole if you have to, go through several taps per hole, rather than break a tap, especially in Titanium. Use a fresh tap per bolster, especially if titanium, it may even take two taps per bolster. I have had many situations where it’s taken up to eight hours to remove a broken tap! Not fun! I have recently discovered that the local conventional EDM place, can blast out broken taps very effectively for about $60 a pop. Or in the case of in Ti, broken taps can just be etched out without affecting the Ti.
53 "ALCHEMY" by Jensen Knives
53: Now that I no longer need the holes in the tang as guidance holes, I can tap them. I am going to hand tap the holes with a tap wrench using a 440-thread size tap.
Using a hand tap with a 440 tap to thread the previously drilled holes. Tapping involves patience above all things. In order to cut threads into the sides of drilled holes, taps have to be extremely hard; as such they are extremely brittle and are prone to breakage. Use new, sharp taps with cutting fluid. Carefully, and constantly checking for straightness, gently insert the tip of the tap into the hole, and with a little pressure give it a little clockwise twist to get it started. This is the only time you should use a little pressure, once you feel it bite, let the tap do the rest of the work. Using small 1/8-1/4 turns, twist the tap farther into the hole, back it out, then repeat just a little past where you had previously gotten. You will be able to feel when you are biting into fresh material. If you hear a loud squeak, immediately stop, and reverse the tap!! It’s better to take a half an hour per hole if you have to, go through several taps per hole, rather than break a tap, especially in Titanium. Use a fresh tap per bolster, especially if titanium, it may even take two taps per bolster. I have had many situations where it’s taken up to eight hours to remove a broken tap! Not fun! I have recently discovered that the local conventional EDM place, can blast out broken taps very effectively for about $60 a pop. Or in the case of in Ti, broken taps can just be etched out without affecting the Ti.