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Twist Drill Bit |
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General Guidelines for 4-Facet Grind | ||||||||
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Drill Bit SIze | Point Angle | Clearance Angle | Notes | |||||
Inch Decimal |
Inch Fraction |
Metric (mm) | Wire Number | Letter | Mild Metal, Wood | Hard Steel | ||
< 0.125 | < 1/8 | < 3.0 | > 31 | 118° | 14° | 11° | Can't use the Tormek DBS-22 Drill Bit Sharpening Attachment with these bits -- they are too small. However, one sharpener has used a precision pen vice (like the Starrett 166C ) with the Tormek DBS-22 to hold bits as small as #61 (5/128 in. / 1 mm). | |
0.125 - 0.250 | 1/8 - 1/4 | 3.0 - 6.0 | 31 - 1 | A - E | 118° |
14° |
11° |
Bits as small as 1/8 inch can be held in the Tormek DBS-22, but they can flex easily. A pin vice can assist with reducing this flex. |
0.250 - 0.500 | 1/4 - 1/2 | 6.5 - 12.0 | F - Z | 118° |
11° |
9° |
||
0.500 - 0.875 | 1/2 - 7/8 | 12.5 - 22.0 | 118° |
9° |
7° |
|||
> 0.875 | > 7/8 | > 22.0 | Can't use the Tormek DBS-22 Drill Bit Sharpening Attachment with these bits -- they are too large |
Material-Based Guidelines | ||||||
---|---|---|---|---|---|---|
Material Type | Point Angle | Clearance Angle | Notes | |||
Recom. | Range | Recom. | Range | |||
Aluminium | 118° |
90 - 130° |
(as above) |
12 - 15° |
Clearance angles based on drill bit size should be used. | |
Armour Plate | 135° |
135 - 140° |
7° |
6 - 9° |
||
Brass | 118° |
118° |
(as above) |
12 - 15° |
Clearance angles based on drill bit size should be used. | |
Bronze | 118° |
110 - 118° |
(as above) |
12 - 15° |
Clearance angles based on drill bit size should be used. | |
Bronze, High Tensile | 105° |
100 - 110° |
(as above) |
12 - 15° |
Clearance angles based on drill bit size should be used. | |
Cast Iron, Soft | 95° |
90 - 100° |
(as above) |
12 - 15° |
Clearance angles based on drill bit size should be used. | |
Cast Iron, Medium | 105° |
100 - 110° |
(as above) |
12 - 15° |
Clearance angles based on drill bit size should be used. | |
Cast Iron, Hard | 110° |
100 - 118° |
9° |
8 - 12° |
||
Cast Iron, Chilled | 118° |
118 - 135° |
7° |
5 - 9° |
||
Copper | 118° |
100 - 118° |
14° |
12 - 15° |
||
Iron, Malleable | 95° |
90 - 100° |
14° |
12 - 15° |
||
Magnesium and Alloys | 95° |
70 - 118° |
14° |
12 - 15° |
||
Monel Nickel | 120° |
118 - 125° |
11° |
10 - 12° |
||
Nickel Alloys | 135° |
135 - 140° |
7° |
5 - 7° |
||
Plastic, Hot Set | 90° |
60 - 90° |
11° |
10 - 12° |
Minimum point angle on the Tormek DBS-22 Drill Bit Sharpening Attachment is 90°. | |
Plastic, Cold Set | 125° |
118 - 135° |
14° |
12 - 20° |
||
Steel, Low Carbon | 118° |
110 - 118° |
9° |
7 - 9° |
||
Steel, Medium Carbon | 118° |
118 - 125° |
9° |
7 - 9° |
||
Steel, High Carbon | 130° |
118 - 145° |
9° |
7 - 9° |
||
Steel, Forged | 130° |
118 - 145° |
11° |
7 - 12° |
||
Steel, Alloy | 118° |
118 - 125° |
11° |
10 - 12° |
||
Steel, Stainless | 115° |
110 - 118° |
11° |
8 - 12° |
||
Steel, Stainless, Hard | 125° |
118 - 135° |
7° |
6 - 8° |
||
Steel, Manganese | 145° |
140 - 150° |
9° |
7 - 10° |
Good videos showing the use of the Tormek DBS-22 Drill Bit Sharpening Attachment:
It's time for drill bit sharpening! Learn how to sharpen your drill bits with maximum precision, to the greatest sharpness. We will show you how to create a 4-facet point which gives the ideal cutting performance. |
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