Formulas, Calculations and General Technical Information

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How to Calculate CLPT Factor for Standard Tools

How to Calculate CLPT Factor for Metric Tools

Robbjack Tool Features

General Machining Guidelines

Application Guidelines

Milling
Information

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CLPT Factor for Standard Tools

CLPT Factor - Standard

Chip Load per Tooth = Tool Diameter x CLPT Factor

Examples on how to calculate the CLPT:

Multiply Tool Diameter by CLPT Factor -
Use a Minimum Chip Load per Tooth of .0001"

Example 1:

5/8" diameter tool cutting 6061 T6 Aluminum:
.625 x .0256 = .016" CLPT

Example 2:

3/16" diameter tool cutting 304 stainless:
.1875 x .0032 = .0006" CLPT

CLPT Factor for MetricTools

CLPT Factor - Metric

Chip Load per Tooth = Tool Diameter x CLPT Factor

Examples on how to calculate the CLPT:

Multiply Tool Diameter by CLPT Factor -
Use a Minimum Chip Load per Tooth of .0025mm

Example 1:

3mm diameter tool cutting 6061 T6 Aluminum:
.3mm x .0256 = .0768mm CLPT

Example 2:

12mm diameter tool cutting 304 stainless:
12mm x .0032 = .0384mm CLPT

RJ Tool Features

Tool Features

RobbJack end mills, saws, and router bits set the industry standard for close tolerances and consistent performance.

  1. Radial Rake controlled within +/-1° to ensure consistent tool performance
  2. Center cutting on every two flute, three and four flute end mills
  3. Web, cheek, ramp and helix angle ground to geometrically controlled tolerances to ensure faster chip flow
  4. Geometrically controlled ends, meet or exceed NAS specifications
  5. T.I.R. controlled to 1/3 industry standards to ensure equal flute wear
  6. O.D. tolerances of +.001”/-.000” on selected series, with primary relief angle super finished to 4 to 6 RMS on all end mills
  7. Weldon Shanks on selected series
  8. Overall length ground and corners chamfered on all shanks to prevent scoring of tool holders
  9. Tightest Shank Tolerances in the Industry
    • -.0001”/-.0002” as Standard
    • -.002/-.005 in Metric sizes
Grade Selection Chart

General Guidelines

Select the shortest flute length possible for the application.

Shorter flute length end mills offer better stability and increased feed rates.

Select the largest diameter possible for the application.

Increasing diameter by 10% provides 25% more strength.

Applications Guidelines

Application Guidelines

Rough Slotting/Pocketing

Two and three flute end mills can be used in non-ferrous and ferrous materials with depth of cuts not exceeding one diameter per pass.

Three and four flute carbide Ruffers can be used for rough pocketing and profiling operations in many ferrous materials with radial depths of cuts not exceeding 25% of the diameter.

Finish Slotting/Peripheral/Pocketing

Three, four and six flute end mills offer greater stability with increased feed rates for finishing.

Milling: Conventional or Climb?

Milling: Conventional Versus Climb

RobbJack recommends Climb Milling (as opposed to Conventional Milling) for most applications (assuming back-lash control in the machine).

Climb Milling generally allows better flute engagement in the material, resulting in more efficient machining and superior part finishes.

Conventional Milling can lead to work hardening in some ferrous materials.


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