Metal Lathe Tools : High Speed Steel (HSS)

  • Angles shown are good for hobbyists; grinds for production shops should consult a specialist.

  • When both a relief and a clearance angle are outlined (e.g., Side Relief and Front Relief), this is done to facilitate easier resharpening.
    • It is analogous to Secondary Bevels on woodworking chisels.
    • Resharpening should be done when the wear land reaches 1.5 mm (1/16 inch) high.

  • Angles shown are the effective angles, not the ground angles. Effective angles are increased or decreased, based on the angle by which the tool is presented against the work. Additionally, the vertical alignment of the tool (vs. the center line of the work) can also change the effective Front Relief Angle.

  • All angles are given the nomenclature designated by the American Standards Association (ASA).
Carbide vs. HSS
Material Compressive Strength Shear Strength Max Usable Temp.
Carbide Higher Lower 1,800 °F
HSS Lower Higher 950 - 1,100 °F

* Temperature at which the tool material begins to soften appreciably. For HSS, it depends on the level of cobalt in the HSS.


Tool Shape - End View

Side Clearance Angle should be 4° to 6° greater than Side Relief Angle.

In selecting the Side Relief Angle, the sharpener should :

  • carefully chose the correct angle, as a deviation of even 2° (plus or minus) will lower tool life appreciably.
  • chose the lower angle from the table below for heavy cutting
  • chose the higher angle from the table below for finish cutting.
  • increase the angle by +2° when making high impact cuts (e.g., work with significant gaps or hard inclusions).
Material Side Rake Angle Side Relief Angle Side Clearance Angle Comments
Aluminium
20° - 30°
12° - 14°
Side Relief
+ 4° - 6°
Aluminum Bronze
15° - 20°
10° - 12°
Manganese Bronze
10° - 16°
9° - 11°
Bronze Castings
15° - 20°
10° - 12°
Cast Iron - Soft (170 Brinell)
12° - 18°
8° - 10°
Cast Iron - Medium (250 Brinell)
10° - 15°
7° - 9°
Cast Iron - Hard (400 Brinell)
5° - 10°
5° - 7°
Cast Iron - Chilled
-3° - +5°
3° - 5°
Copper
20° - 30°
10° - 12°
Monel
10° - 15°
8° - 10°
Magnesium
25° - 35°
12° - 14°
Maleable Iron
10° - 15°
7° - 9°
Plastics
20° - 30°
14° - 16°
Steel - SAE 1020
15° - 25°
9° - 11°
Steel - SAE 1040
12° - 20°
8° - 10°
Steel - SAE 1095 or 52100
10° - 15°
7° - 9°
Steel - SAE 2340
10° - 15°
7° - 9°
Steel - SAE 6150
8° - 14°
7° - 9°
Steel - Heat Treated to 350 Brinell
5° - 10°
6° - 8°

Tool Shape - Side View

Front Clearance Angle should be 4° to 6° greater than the Front Relief Angle.

The Back Rake Angle, as shown in the picture to the right, is positive.

Use Front Relief Angle Front Clearance Angle Bake Rake Angle Comments
Aluminium
12° - 14° Front Relief
+ 4° - 6°
5° - 8°
Aluminum Bronze
10° - 12°
Manganese Bronze
9° - 11°
Bronze Castings
10° - 12°
Cast Iron - Soft (170 Brinell)
8° - 10°
Cast Iron - Medium (250 Brinell)
7° - 9°
Cast Iron - Hard (400 Brinell)
5° - 7°
Cast Iron - Chilled
3° - 5°
Copper
10° - 12°
Monel
8° - 10°
Magnesium
12° - 14°
Maleable Iron
7° - 9°
Plastics
14° - 16°
Steel - SAE 1020
9° - 11°
Steel - SAE 1040
8° - 10°
Steel - SAE 1095 or 52100
7° - 9°
Steel - SAE 2340
7° - 9°
Steel - SAE 6150
7° - 79
Steel - Heat Treated to 350 Brinell
6° - 8°

Tool Shape - Top View
  • Nose Radius
    • For HSS, the radius of the Nose Radius should be the greater of the following two values :
      • 4 x the feed rate
      • depth of cut / 4

    Increases in the Side Cutting Edge Angle will :

    • decrease chip thickness and increase chip width (retaining the same area of the chip)
    • decrease power usage
    Use Side Cutting Edge (SCE) Angle Front Cutting Edge Angle Comments
    Range Recom.
    Roughing Out 10° - 60° 30° 5° - 10° It is recommended that the Point and the Front Cutting Edge Angles match.
    Finishing - if a square corner is required n/a 5° - 10° If a square edge is not needed, a point angle (or a nose radius) can be used.


    Notes & Comments
    Information regarding Grindstones


    Tormek Tool Rest SVD-110
    Tormek AngleMaster WM-200

    Tormek is a copyrighted logo of Tormek AB. Its presentation on this site is used to help the user quickly understand when specific Tormek tools, jigs, or setting are being used. For specific information regarding Tormek AB, or its products, please refer to the www.Tormek.com.


    About this site
    Remember : The goal of sharpening is to produce sharp tools, and these tools can injure you if mishandled. Safety measures should be followed to protect yourself and those in your shop. Be sure to read and follow all instructions from the manufacturer, and and utilize proper safety equipment. Never consume alcohol or anything that could impair your judgement before sharpening tools, or using sharp tools. Comments can be sent via eMail to me at SharpeningHandbook@Gmail.com.