Broken Tap Removal Tools – Tech Help/How To

Armor Mills and Armor Mills: Broken Tap Removal Tools Help and FAQ

Use an Armor Drill when the tap or drill is broken off above the surface of the workpiece or when the broken tap or drill has a flat top surface that will not cause the drill tip to walk or deflect.

• It is recommended to use in a rigid machine (machining centers, kneemills, and lathes) with the parts held securely.
• Use of coolant is typically recommended and will extend the life of the tool bit.
• Using the handwheel at the lowest speed, feed very slowly and keep a steady feedrate until the tool has plunged far enough into the broken tool to encounter a stable cutting condition. In other words, as the tool begins cutting into the uneven jagged surface of the broken tool, feed extremely slowly to prevent the tool from walking which will put high side loads on the cutting tool and lead to breakage.
• It is important to prevent the tools from walking or deflecting, especially when first contacting the uneven part surface.
• Once the tool is fully into the cut and seems stable, feeding with the cnc control at the noted feeds and speeds is possible.
• Peck or stop frequently to remove chips from the hole.
• If the part needs to be drilled with a hand drill, operate the drill at faster rpms, use a strong, steady force, and keep the drill as straight as possible.
• Note: Consider the noted feeds and speeds as a reference point. Variations in the table may be required depending on material being machined and cutting conditions. In particular, stone such as granite and marble have different machining properties among different varieties and even at different spots within the same piece of stone
• See all available tool sizes and purchase Armor Drills here.

Please note as with all machining, it is important to take appropriate safety precautions.

RPM= Spindle Speed
D = Diameter of tool
IPR = Inches per rev
IPM = Inches per minute
IPT = Inches per tooth
SFM and SFPM = Surface feet per minute 

Armor Mills can be used when the tap or drill is broken off below the surface of the workpiece or when the broken tap or drill has an uneven top surface tat would cause the tool tip to walk or deflect.

Details & Speeds and Feeds:

• It is recommended to use the Armor Mill in a rigid machine (machining centers, kneemills, and lathes) with the parts held securely.
• Using the handwheel at the lowest speed, feed very slowly and keep a steady feedrate until the tool has plunged far enough into the broken tool to encounter a stable cutting condition. In other words, as the tool begins cutting into the uneven jagged surface of the broken tool, feed extremely slowly to prevent the tool from walking which will put high side loads on the cutting tool and lead to breakage.
• It is important to prevent the tools from walking or deflecting, especially when first contacting the uneven part surface.
• Once the tool is fully into the cut and seems stable, feeding with the cnc control at the noted feeds and speeds is possible.
• Peck or stop frequently to remove chips from the hole.
• If the part needs to be drilled with a hand drill, operate the drill at faster rpms, use a strong, steady force, and keep the drill as straight as possible.
• Use of coolant is typically recommended and will extend the life of the tool bit.
• Note: Consider the noted feeds and speeds as a reference point. Variations in the table may be required depending on material being machined and cutting conditions. In particular, stone such as granite and marble have different machining properties among different varieties and even at different spots within the same piece of stone.
• See all available tool sizes and purchase Armor Mills here.

Please note as with all machining, it is important to take appropriate safety precautions.

RPM = (SFPM x 3.82) / D
IPM = (No. of teeth) x IPT x RPM
RPM= Spindle Speed
D = Diameter of tool
IPR = Inches per rev
IPM = Inches per minute
IPT = Inches per tooth
SFM and SFPM = Surface feet per minute