Feeds and Speeds for Armor Mills and Armor Drills & Broken Tap Removal Tips
Reference the below tables for general Feed and Speed Rates
- Table 1 - Armor Mills
- Table 2 - Armor Drills
- Broken Tap Removal Tools - Tips
Armor Mills - for Granite, Armor Plate, Hard Materials
Armor Mills are designed for use with rigid cnc machines when cutting or engraving granite or other hard materials.
Control of the depth of cut, the spindle speed, and the cutting feedrate is critical to achieve maximum tool life.
Cutting granite or other extremely hard materials may not be possible with the use of a hand operated tool or the life of the tools may be significantly reduced.
2L inc. has tested the armor mills on granite with a rigid cnc machine and a rigidly held workpiece.
Feedrates are below:
Material | Recommended Speed (SFPM) and Feedrates (IPT) | Cutting the below piece of granite, 2L used: | |
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Cutter Diameter = .078" Depth of Cut per pass = .020" |
Cutter Diameter = .125" Depth of Cut per pass = .030" |
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Granite Stone Armor Plate Hardened Steel |
50- 125 SFPM 0.0001-0.001 IPT |
6000 RPM F5.0 IPM Plunge = 2.0 IPM |
6000 RPM F6.0 IPM Plunge = 2.0 IPM |
Broken Taps and Drills |
50- 125 SFPM 0.0001-0.0005 IPT |
1500-2500 RPM Plunge = 0.1 IPM |
1500-2500 RPM Plunge = 0.1 IPM |
Copyright © 2020, 2L inc., www.2Linc.com |
- Please note as with all machining, it is important to take appropriate safety precautions.
- Use of coolant is typically recommended and will extend the life of the tool bit.
- The sample of granite shown below was machined at the specific feeds and speeds listed above in the table. The Armor Mills successfully machined for 30 minutes at the above conditions to complete the sample.
Note: Consider the above feeds and speeds as a reference point. Variations in the above table may be required depending on material being machined and cutting conditions.
To remove broken taps and drills, it is recommended to feed the tools by hand (hand wheel on lowest 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.
Once the tool is fully into the cut and seems stable, feeding with the cnc control at the above feeds and speeds is possible.
Stones such as granite and marble have different machining properties among different varieties and even at different spots within the same piece of stone.
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.
Armor Drills
Material | Recommended Speed (SFPM) and Feedrates (IPT) | Cutter Diameter = .078" | Cutter Diameter = .125" |
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Granite Stone |
50- 125 SFPM 0.0001-0.0005 IPT |
1500-2500 RPM F5.0 IPM Plunge = 1.5 IPM |
1500-2500 RPM F6.0 IPM Plunge = 1.5 IPM |
Broken Taps and Drills Armor Plate Hardened Steel and Drills |
50- 125 SFPM 0.0001-0.0005 IPT |
1500-2500 RPM Plunge = 0.1 IPM |
1500-2500 RPM Plunge = 0.1 IPM |
Copyright © 2020, 2L inc., www.2Linc.com |
Please note as with all machining, it is important to take appropriate safety precautions.
Note: Consider the above feeds and speeds as a reference point. Variations in the above table may be required depending on the material being machined and cutting conditions.
Use of coolant is typically recommended and will extend the life of the engraving tool bit.
To remove broken taps and drills, it is recommended to feed the tools by hand (hand wheel on lowest 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.
Once the tool is fully into the cut and seems stable, feeding with the cnc control at the above feeds and speeds is possible.
Stones such as granite and marble have different machining properties among different varieties and even at different spots within the same piece of stone.
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.
Use the Armor Mill 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 that would cause the Armor Drill tip to walk or deflect. These tools are manufactured in house with a Premium, Ultra Fine, Nano Grade, Solid Carbide for maximum tool strength.
Order Armor Mills Here
If possible, use a punch to make the top surface of the broken tap/drill flat before drilling. | Drill at 1,200-2,500 RPM. Feed extremely slow (especially when first contacting uneven surface). |
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Use the 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. These tools are manufactured in house of a Premium, Ultra Fine, Nano Grade, Solid Carbide for maximum tool strength.
Order Armor Drills Here
Remove excess drill/tap material to create as flat a surface as possible. | Spot drill the broken tap with the largest dia. Armor Drill. Drill at 1,200-2,500 RPM. | Drill down through the broken tap. Use coolant if possible, peck and flush out chips with air blast. Remove remnants of broken tap with pick. |
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It is recommended that both the Armor Drill and Armor Mill tools be used in rigid machines (machining centers, knee mills, lathes) with the parts held securely. Using the hand wheel at the lowest speed, feed very slowly and keep a steady feedrate. 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. It is important to prevent the tools from walking or deflecting, especially when first contacting the uneven part surface.
As with all machining, it is necessary to take appropriate safety precautions.
