Thread Milling

THREADING | Solid Carbide and Indexable Thread Mills

Thread Mill Pre-Drill Information

A

Linear Feed Rate (LFR)

DRILLING

RPM = Revolutions per minute

LFR = RPM • (IPT • Number of flutes)

IPT = Recommended feed (inch / tooth)

Surface Feet per Minute (SFM)

RPM = Revolutions per minute

SFM = RPM • 0.262 • Diameter

B

BORING

Revolutions per Minute (RPM)

SFM = Surface feet per minute

RPM = SFM • 3.82 Diameter

Adjusted Feed Rate (AFR) - For Internal Threading

C

LFR = Linear feed rate

AFR = Major Diameter - Cutter Diameter Major Diameter

[LFR]

REAMING

NOTICE: The above formula on an internal thread program adjusts the linear feed rate to be applied to the outer diameter instead of the center of the cutting tool. If the feed rate is not adjusted, the excessive feed rate will cause the thread mill cutting edges to fail.

Example of an Internal Adjusted Feed Rate Calculation:

D

BURNISHING

Cast iron 125 BHN with a 1/2-13 thread form using AccuThread 856 solid carbide (TMUK0500-13)

SFM • 3.82 Diameter

RPM = 675 • 3.82 0.350

RPM =

STEP 1:

RPM = 7367

E

STEP 2:

LFR = RPM • (IPT • Number of flutes)

LFR = 7367 • (0.0010 • 4)

LFR = 29.47 IPM

THREADING

Major Diameter - Cutter Diameter Major Diameter

AFR = 0.500 - 0.350 0.500

[29.47]

AFR =

[LFR]

STEP 3:

AFR = 8.84 IPM

X

SPECIALS

E: 50

www.alliedmachine.com | 1.330.343.4283

Made with FlippingBook - Online catalogs