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).

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.
Material	Front Relief Angle	Front Clearance Angle	Back 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° - 9°
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	0°	5° - 10°	If a square edge is not needed, a point angle (or a nose radius) can be used.

Notes & Comments

Information regarding Grindstones

If grinding this on a high speed grinder, be sure to manage the temperature so that the temper is not lost due to overheating. If there is a carbide insert, DO NOT cool by dipping in water. This will cause the carbide to crack due to shocks. Otherwise, cool by dipping as needed in water.

Contour Gauge

For resharpening, a contour gauge like shown to the left is recommended. One should be made for each tool, and it should be numbered to match the tool's number.

More Information

Books & Papers

• The definitive source is Leo J. St. Clair's book from 1952 titled, Design and Use of Cutting Tools. He was working in the industry as it was changing from HSS to carbide, so both are covered well. His experimental data helps validate or disprove many theories. Unfortunately, this book is hard to find.

Videos & Presentations

• Tormek Tool Rest SVD-110 (YouTube video)
• Tormek AngleMaster WM-200 (YouTube video)

Web Sites

• Conversion of Brinell vs. Rockwell hardness measurements.