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タップのネジ下穴径表
メートル並目ねじ
| ねじの呼び | ピッチ | ドリル径 |
|---|---|---|
| M1 | 0.25 | 0.75 |
| M1.1 | 0.25 | 0.85 |
| M1.2 | 0.25 | 0.95 |
| M1.4 | 0.3 | 1.1 |
| M1.6 | 0.35 | 1.25 |
| M1.8 | 0.35 | 1.45 |
| M2 | 0.4 | 1.6 |
| M2.2 | 0.45 | 1.75 |
| M2.5 | 0.45 | 2.1 |
| M3 | 0.5 | 2.5 |
| M3.5 | 0.6 | 2.9 |
| M4 | 0.7 | 3.3 |
| M4.5 | 0.75 | 3.8 |
| M5 | 0.8 | 4.2 |
| M6 | 1 | 5 |
| M7 | 1 | 6 |
| M8 | 1.25 | 6.8 |
| M9 | 1.25 | 7.8 |
| M10 | 1.5 | 8.5 |
| M11 | 1.5 | 9.5 |
| M12 | 1.75 | 10.3 |
| M14 | 2 | 12 |
| M16 | 2 | 14 |
| M18 | 2.5 | 15.5 |
| M20 | 2.5 | 17.5 |
| M22 | 2.5 | 19.5 |
| M24 | 3 | 21 |
| M27 | 3 | 24 |
| M30 | 3.5 | 26.5 |
| M33 | 3.5 | 29.5 |
| M36 | 4 | 32 |
| M39 | 4 | 35 |
| M42 | 4.5 | 37.5 |
| M45 | 4.5 | 40.5 |
| M48 | 5 | 43 |
メートル細目ねじ
| ねじの呼び | ピッチ | ドリル径 |
|---|---|---|
| M2.5 | 0.35 | 2.2 |
| M3 | 0.35 | 2.7 |
| M3.5 | 0.35 | 3.2 |
| M4 | 0.5 | 3.5 |
| M4.5 | 0.5 | 4 |
| M5 | 0.5 | 4.5 |
| M5.5 | 0.5 | 5 |
| M6 | 0.75 | 5.3 |
| M7 | 0.75 | 6.3 |
| M8 | 1 | 7 |
| M8 | 0.75 | 7.3 |
| M9 | 1 | 8 |
| M9 | 0.75 | 8.3 |
| M10 | 1.25 | 8.8 |
| M10 | 1 | 9 |
| M10 | 0.75 | 9.3 |
| M11 | 1 | 10 |
| M11 | 0.75 | 10.3 |
| M12 | 1.5 | 10.5 |
| M12 | 1.25 | 10.8 |
| M12 | 1 | 11 |
| M14 | 1.5 | 12.5 |
| M14 | 1 | 13 |
| M15 | 1.5 | 13.5 |
| M15 | 1 | 14 |
| M16 | 1.5 | 14.5 |
| M16 | 1 | 15 |
| M17 | 1.5 | 15.5 |
| M17 | 1 | 16 |
| M18 | 2 | 16 |
| M18 | 1.5 | 16.5 |
| M18 | 1 | 17 |
| M20 | 2 | 18 |
| M20 | 1.5 | 18.5 |
| M20 | 1 | 19 |
| M22 | 2 | 20 |
| M22 | 1.5 | 20.5 |
| M22 | 1 | 21 |
| M24 | 2 | 22 |
| M24 | 1.5 | 22.5 |
| M24 | 1 | 23 |
| M25 | 2 | 23 |
| M25 | 1.5 | 23.5 |
| M25 | 1 | 24 |
| M26 | 1.5 | 24.5 |
| M27 | 2 | 25 |
| M27 | 1.5 | 25.5 |
| M27 | 1 | 26 |
| M28 | 2 | 26 |
| M28 | 1.5 | 26.5 |
| M28 | 1 | 27 |
| M30 | 3 | 27 |
| M30 | 2 | 28 |
| M30 | 1.5 | 28.5 |
| M30 | 1 | 29 |
| M32 | 2 | 30 |
| M32 | 1.5 | 30.5 |
| M33 | 3 | 30 |
| M33 | 2 | 31 |
| M33 | 1.5 | 31.5 |
| M35 | 1.5 | 33.5 |
| M36 | 3 | 33 |
| M36 | 2 | 34 |
| M36 | 1.5 | 34.5 |
| M38 | 1.5 | 36.5 |
| M39 | 3 | 36 |
| M39 | 2 | 37 |
| M39 | 1.5 | 37.5 |
| M40 | 3 | 37 |
| M40 | 2 | 38 |
| M40 | 1.5 | 38.5 |
| M42 | 4 | 38 |
| M42 | 3 | 39 |
| M42 | 2 | 40 |
| M42 | 1.5 | 40.5 |
| M45 | 4 | 41 |
| M45 | 3 | 42 |
| M45 | 2 | 43 |
| M45 | 1.5 | 43.5 |
| M48 | 4 | 44 |
| M48 | 3 | 45 |
| M48 | 2 | 46 |
| M48 | 1.5 | 46.5 |
| M50 | 3 | 47 |
| M50 | 2 | 48 |
| M50 | 1.5 | 48.5 |
ユニファイ並目ねじ（UNC）
| ねじの呼び | ドリル径 |
|---|---|
| No.1-64UNC | 1.55 |
| No.2-56UNC | 1.8 |
| No.3-48UNC | 2.1 |
| No.4-40UNC | 2.3 |
| No.5-40UNC | 2.6 |
| No.6-32UNC | 2.8 |
| No.8-32UNC | 3.4 |
| No.10-24UNC | 3.9 |
| No.12-24UNC | 4.5 |
| 1/4-20UNC | 5.1 |
| 5/16-18UNC | 6.6 |
| 3/8-16UNC | 8 |
| 7/16-14UNC | 9.4 |
| 1/2-13UNC | 10.8 |
| 9/16-12UNC | 12.2 |
| 5/8-11UNC | 13.6 |
| 3/4-10UNC | 16.5 |
| 7/8-9UNC | 19.5 |
| 1-8UNC | 22.2 |
| 1-1/8-7UNC | 25 |
| 1-1/4-7UNC | 28.2 |
| 1-3/8-6UNC | 30.8 |
| 1-1/2-6UNC | 34 |
| 1-3/4-5UNC | 39.5 |
| 2-4-1/2UNC | 45.2 |
ユニファイ細目ねじ（UNF）
| ねじの呼び | ドリル径 |
|---|---|
| No.0-80UNF | 1.25 |
| No.1-72UNF | 1.55 |
| No.2-64UNF | 1.85 |
| No.3-56UNF | 2.1 |
| No.4-48UNF | 2.4 |
| No.5-44UNF | 2.7 |
| No.6-40UNF | 2.9 |
| No.8-36UNF | 3.5 |
| No.10-32UNF | 4.1 |
| No.12-28UNF | 4.6 |
| 1/4-28UNF | 5.5 |
| 5/16-24UNF | 6.9 |
| 3/8-24UNF | 8.5 |
| 7/16-20UNF | 9.9 |
| 1/2-20UNF | 11.5 |
| 9/16-18UNF | 12.9 |
| 5/8-18UNF | 14.5 |
| 3/4-16UNF | 17.5 |
| 7/8-14UNF | 20.5 |
| 1-12UNF | 23.2 |
| 1-1/8-12UNF | 26.5 |
| 1-1/4-12UNF | 29.5 |
| 1-3/8-12UNF | 32.8 |
| 1-1/2-12UNF | 36 |
ウィット並目ねじ
| ねじの呼び | ドリル径 |
|---|---|
| W1/8 | 2.6 |
| W3/16 | 3.7 |
| W1/4 | 5.1 |
| W5/16 | 6.6 |
| W3/8 | 8.0 |
| W7/16 | 9.4 |
| W1/2 | 10.7 |
| W9/16 | 12.3 |
| W5/8 | 13.7 |
| W3/4 | 16.7 |
| W7/8 | 19.5 |
| W1 | 22.4 |
| W1-1/8 | 25.0 |
| W1-1/4 | 28.3 |
| W1-3/8 | 30.5 |
| W1-1/2 | 33.8 |
| W1-5/8 | 36.0 |
| W1-3/4 | 39.2 |
| W1-7/8 | 41.8 |
| W2 | 45 |
インサート用（メートル並目ネジ）
| ねじの呼び | ピッチ | ドリル径 |
|---|---|---|
| M2.5 | 0.45 | 2.6 |
| M2.6 | 0.45 | 2.7 |
| M3 | 0.5 | 3.1 |
| M4 | 0.7 | 4.2 |
| M5 | 0.8 | 5.2 |
| M6 | 1 | 6.3 |
| M8 | 1.25 | 8.4 |
| M10 | 1.5 | 10.5 |
| M12 | 1.75 | 12.5 |
| M14 | 2 | 14.5 |
| M16 | 2 | 16.5 |
| M18 | 2.5 | 19.0 |
| M20 | 2.5 | 21.0 |
| M22 | 2.5 | 23.0 |
| M24 | 3 | 25.0 |
インサート用（メートル細目ネジ）
| ねじの呼び | ピッチ | ドリル径 |
|---|---|---|
| M10 | 1 | 10.3 |
| M10 | 1.25 | 10.4 |
| M12 | 1.25 | 12.5 |
| M12 | 1.5 | 12.5 |
| M14 | 1.5 | 14.5 |
| M16 | 1.5 | 16.5 |
| M18 | 1.5 | 18.5 |
| M20 | 1.5 | 20.5 |
| M20 | 2 | 20.5 |
| M22 | 1.5 | 22.5 |
| M24 | 1.5 | 24.5 |
| M24 | 2 | 24.5 |
| M30 | 1.5 | 30.5 |
インサート用（ユニファイ並目ネジ）
| ねじの呼び | ドリル径 |
|---|---|
| No.2-56UNC | 2.3 |
| No.3-48UNC | 2.7 |
| No.4-40UNC | 3.0 |
| No.5-40UNC | 3.3 |
| No.6-32UNC | 3.7 |
| No.8-32UNC | 4.4 |
| No.10-24UNC | 5.1 |
| No.12-24UNC | 5.7 |
| 1/4-20UNC | 6.7 |
| 5/16-18UNC | 8.4 |
| 3/8-16UNC | 10.0 |
| 7/16-14UNC | 11.5 |
| 1/2-13UNC | 13.1 |
| 9/16-12UNC | 14.7 |
インサート用（ユニファイ細目ネジ）
| ねじの呼び | ドリル径 |
|---|---|
| No.4-48UNF | 3.0 |
| No.6-40UNF | 3.7 |
| No.8-36UNF | 4.4 |
| No.10-32UNF | 5.0 |
| 1/4-28UNF | 6.6 |
| 5/16-24UNF | 8.2 |
| 3/8-24UNF | 9.8 |
| 7/16-20UNF | 11.5 |
| 1/2-20UNF | 13.1 |
| 9/16-18UNF | 14.7 |
| 5/8-18UNF | 16.3 |
| 3/4-16UNF | 19.5 |
| 7/8-14UNF | 22.7 |
| 1-12UNF | 26.0 |
タップによりめねじを切る場合に、タップ下穴をあける必要があります。下記にそれぞれのねじ規格による標準の下穴径を記載します。被削材の種類やタップの種類により最適な下穴径は異なりますので、下表はあくまでも標準値とお考え下さい。