Armor Mills

Machine Granite, Armor Plate, Hardened Steels and Very Tough Materials – Drill Out Broken Taps and Drills

Armor Mills-Machine Granite, Armor Plate, Drill out Broken Taps, Drills

The Armor Mill is a solid carbide, rugged 2 flute end mill style tool with a square cutting edge.

Machine and cut many extremely hard and difficult materials such as Granite, Armor Plate, Stone, Hardened Steel, Marble, High Speed Steel, Concrete, Brick, Cobalt Steel, and more.

Drill out broken taps and drills with the Armor Mill tool.  Drill into rough and jagged shaped broken drills or taps where other tools might walk unless spot drilled with a larger drill.

  • Designed for use in a rigid tool holder for rotary machining.
  • Solid Carbide.
  • Manufactured in house.
  • 1,000s of tools in stock.
  • Same day shipping.

View options and pricing.

View How To’s.

  • Tool Shank Diameters:  .125″ (1/8″) – .500″ (1/2″).
  • Cutter Diameters:  .078″ (5/64″) – .500″ (1/2″).
  • Overall Lengths:  2.0″, 2.5″, and 3.0″.
  • Solid Carbide:  Produced from premium, ultra-fine nano grade carbide for maximum tool strength.

Custom Tools are produced in house with quick turn around.

If you do not see a size you are looking for Contact Us or send us a Custom Tool Request.

  • Armor Mills are designed for use in a rigid machine (CNC Machines, Machining Centers, Kneemills, and Lathes) with the parts held securely.
Armor Mills and Armor Drills Machine Granite
Armor Mills for Granite and Hard Materials
Cutter Dia.Flute LengthShank Dia.OLPart No.PriceBuy
.078" (5/64").375" (4.8x).125" (1/8")2.0"A-125x2.0-.078-.375$17.45

Buy!

.125" (1/8").500" (4x).125" (1/8")2.0"A-125x2.0-.125-.5$19.53

Buy!

.1875" (3/16").750" (4x).1875" (3/16")2.0"A-1875x2.0-.1875-.75$23.76

Buy!

.250" (1/4").80" (3.2x).250" (1/4")2.0"A-250x2.0-.250-.8$28.92

Buy!

.250" (1/4")1.0" (4x).250" (1/4")2.0"A-250x2.0-.250-1.0$34.98

Buy!

.3125" (5/16")1.0" (3.2x).3125" (5/16")2.5"A-312x2.5-.312-1.0$35.83

Buy!

.375" (3/8")1.0" (2.7x).375" (3/8")3.0"A-375x3.0-.375-1.0$41.96

Buy!

.500" (1/2")1.0" (2x).500" (1/2")3.0"A-500x3.0-.500-1.0$58.76

Buy!

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Armor Mills – Operating Info – Speeds and Feeds

Armor Mills and Armor Drills Machine Granite
  • 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.
  • 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 in the following table.
  • The Armor Mills successfully machined for 30 minutes at the above conditions to complete the sample.
  • See details on drilling out Broken Taps here.

Note: Consider the above feeds and speeds as a reference point. Variations in the table may be required depending on material being machined and cutting conditions.
RPM = (SFPM x 3.82) / D
IPM = (No. of teeth) x IPT x RPMRPM= 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

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

 

Material Recommended Speed
(SFPM) and Feedrates (IPT)
Cutting the Shown Piece of Granite, 2L used:
Cutter Diameter = .078″
Depth of Cut per pass = .020″
Cutter Diameter = .125″
Depth of Cut per pass = .030″
Granite
Stone
Armor Plate
Steel
50- 125 SFPM
0.0001-0.001 IPT
6000 RPM
F5.0 IPMPlunge = 2.0 IPM
6000 RPM
F6.0 IPMPlunge = 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 © 2021, 2L inc., www.2Linc.com

Armor Mills

How to Remove Broken Taps and Drills

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

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

Material Recommended Speed
(SFPM) and Feedrates (IPT)
Cutting the Shown Piece of Granite, 2L used:
Cutter Diameter = .078″
Depth of Cut per pass = .020″
Cutter Diameter = .125″
Depth of Cut per pass = .030″
Granite
Stone
Armor Plate
Steel
50- 125 SFPM
0.0001-0.001 IPT
6000 RPM
F5.0 IPMPlunge = 2.0 IPM
6000 RPM
F6.0 IPMPlunge = 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 © 2021, 2L inc., www.2Linc.com
A taps 1

Armor Mill: Step 1

  • If possible, use a punch to make the top surface of the broken tap/drill flat before drilling.
A taps 2

Armor Mills: Step 2

  • Drill at 1,200-2,500 RPM.
  • Feed extremely slow (especially when first contacting uneven surface).