     
   
|
 |
●ねじサイズ選定方法参考
・ねじ山部分の直径をノギスなどで測定します。最低でも0.1mm単位まで測定してください。
小さいサイズの場合はデジカメや携帯電話のカメラ等で定規等と
一緒に撮影し画像を拡大して見ると判別しやすいです。
・一般に使われている2級ねじの場合、ほとんどが規格上の太さより細くなっています。
例:規格上サイズ:M10 実際計測値:9.8〜9.9mm
間違いやすいのはM8のメートルねじと5/16のユニファイねじのように実寸がほとんど同じ場合です。
この場合はピッチで判別します。
・ピッチゲージがある場合はピッチゲージで。無い場合は山と山の間隔を測定します。
・ピッチゲージが無い場合:1インチ(25.4mm)中に何山あるか?
もしくは5山か10山の長さを計りピッチを割り出します。
上記のM8と5/16の場合、M8ならピッチは1.25mm、5/16なら1.41mm(25.4÷18山=約1.41)
ですから 10山の長さが13mmくらいならM8×P1.25、14mmくらいなら5/16UNCとなります。
●ウイットねじとユニファイねじの識別の注意点
建築用のねじの場合、多くはウィットねじが使われているようです。
ユニファイとウィット(正確にはウィットウォース)の同じサイズのねじの場合、
その違いはねじ山の角度です。
ユニファイやメートルねじは、ねじ山の角度が60度なのに比べウィットねじは55度になっています。
ユニファイとウィットが混用した場合、ユニファイの雌ねじジにウィットの雄ねじは入りますが、
その逆は入らないか、若しくは ねじ込むのに抵抗が大きくなります。
どちらにしても、ねじとしての機能を十分発揮できないので危険ですし、
最悪の場合ねじの破壊につながります。
●下表の見方
・ノギスでねじ山外径を測り@である程度のサイズを特定。
・上記の方法でピッチを計測ミリ山であればAインチねじであればBとなります。
(注)あくまでも上記方法は参考となりますので確定の保証は出来ません。あらかじめご了承下さい。
| @ |
A |
B |
|
おねじの
外径(約)mm |
ねじの
呼び*
( )内
市販性無 |
ピッチ
|
1インチ(25.4ミリ)
あたりの山数(山) |
備考 |
| ミリ山ねじ |
インチねじ |
インチねじ |
| 並目 |
細目他 |
ミリ換算
(約) |
ウイットネジ |
ユニファイ
(NC)並目 |
ユニファイ
(NF)細目 |
管用
G(PFねじ) |
| 1.00 |
M1 |
0.25 |
|
|
|
|
|
|
|
| 1.00 |
M1 |
|
0.2 |
|
|
|
|
|
|
| 1.10 |
M1.1 |
0.25 |
|
|
|
|
|
|
|
| 1.10 |
M1.1 |
|
0.2 |
|
|
|
|
|
|
| 1.20 |
M1.2 |
0.25 |
|
|
|
|
|
|
|
| 1.20 |
M1.2 |
|
0.2 |
|
|
|
|
|
|
| 1.40 |
M1.4 |
0.3 |
|
|
|
|
|
|
|
| 1.40 |
M1.4 |
|
0.2 |
|
|
|
|
|
|
| 1.51 |
No.0 |
|
|
0.32 |
|
|
80 |
|
|
| 1.60 |
M1.6 |
0.35 |
|
|
|
|
|
|
|
| 1.60 |
M1.6 |
|
0.2 |
|
|
|
|
|
|
| 1.70 |
(M1.7) |
0.35 |
- |
|
|
|
|
|
|
| 1.70 |
(M1.7) |
|
0.2 |
|
|
|
|
|
|
| 1.80 |
M1.8 |
0.35 |
|
|
|
|
|
|
|
| 1.80 |
M1.8 |
|
0.2 |
|
|
|
|
|
|
| 1.83 |
No.1 |
|
|
0.35 |
|
|
72 |
|
|
| 1.83 |
(No.1) |
|
|
0.40 |
|
(64) |
|
|
|
| 2.00 |
M2 |
0.4 |
|
|
|
|
|
|
|
| 2.00 |
M2 |
|
0.25 |
|
|
|
|
|
|
| 2.16 |
No.2 |
|
|
0.45 |
|
56 |
|
|
|
| 2.16 |
(No.2) |
|
|
0.40 |
|
|
(64) |
|
|
| 2.20 |
M2.2 |
0.45 |
|
|
|
|
|
|
|
| 2.20 |
M2.2 |
|
0.25 |
|
|
|
|
|
|
| 2.30 |
(M2.3) |
0.4 |
- |
|
|
|
|
|
|
| 2.30 |
(M2.3) |
|
0.25 |
|
|
|
|
|
|
| 2.49 |
No.3 |
|
|
0.53 |
|
48 |
|
|
|
| 2.49 |
(No.3) |
|
|
0.45 |
|
|
(56) |
|
|
| 2.50 |
M2.5 |
0.45 |
|
|
|
|
|
|
|
| 2.50 |
(M2.5) |
|
0.35 |
|
|
|
|
|
|
| 2.60 |
M2.6 |
0.45 |
- |
|
|
|
|
|
|
| 2.60 |
(M2.6) |
|
0.35 |
|
|
|
|
|
|
| 2.82 |
N0.4 |
|
|
0.64 |
|
40 |
|
|
|
| 2.82 |
(N0.4) |
|
|
0.53 |
|
|
(48) |
|
|
| 3.00 |
M3 |
0.5 |
|
|
|
|
|
|
|
| 3.00 |
M3 |
|
0.35 |
|
|
|
|
|
|
| 3.00 |
M3 |
|
0.6 |
|
|
|
|
|
旧JIS |
| 3.15 |
No.5 |
|
|
0.64 |
|
40 |
|
|
|
| 3.15 |
(No.5) |
|
|
0.58 |
|
|
(44) |
|
|
| 3.18 |
1/8 |
|
|
0.64 |
40 |
|
|
|
1分 |
| 3.48 |
No.6 |
|
|
0.79 |
|
32 |
|
|
|
| 3.48 |
(No.6) |
|
|
0.64 |
|
|
(40) |
|
|
| 3.50 |
M3.5 |
0.6 |
|
|
|
|
|
|
|
| 3.50 |
M3.5 |
|
0.35 |
|
|
|
|
|
|
| 3.97 |
5/32 |
|
|
0.79 |
32 |
|
|
|
1分2厘5毛 |
| 4.00 |
M4 |
0.7 |
|
|
|
|
|
|
|
| 4.00 |
M4 |
|
0.5 |
|
|
|
|
|
|
| 4.00 |
M4 |
|
0.75 |
|
|
|
|
|
旧JIS |
| 4.14 |
No.8 |
|
|
0.79 |
|
32 |
|
|
|
| 4.14 |
(No.8) |
|
|
0.71 |
|
|
(36) |
|
|
| 4.50 |
M4.5 |
0.75 |
|
|
|
|
|
|
|
| 4.50 |
M4.5 |
|
0.5 |
|
|
|
|
|
|
| 4.76 |
3/16 |
|
|
1.06 |
24 |
|
|
|
1分5厘 |
| 4.80 |
No.10 |
|
|
1.06 |
|
24 |
|
|
|
| 4.80 |
No.10 |
|
|
0.79 |
|
|
32 |
|
|
| 5.00 |
M5 |
0.8 |
|
|
|
|
|
|
|
| 5.00 |
M5 |
|
0.5 |
|
|
|
|
|
|
| 5.00 |
M5 |
|
0.9 |
|
|
|
|
|
旧JIS |
| 5.00 |
(M5.5) |
|
0.9 |
|
|
|
|
|
|
| 5.46 |
No.12 |
|
|
1.06 |
|
24 |
|
|
|
| 5.46 |
(No.12) |
|
|
0.91 |
|
|
(28) |
|
|
| 6.00 |
M6 |
1.0 |
|
|
|
|
|
|
|
| 6.00 |
M6 |
|
0.75 |
|
|
|
|
|
|
| 6.00 |
M6 |
|
0.5 |
|
|
|
|
|
|
| 6.32 |
1/4 |
|
|
1.27 |
|
20 |
|
|
|
| 6.32 |
1/4 |
|
|
0.91 |
|
|
28 |
|
|
| 6.35 |
1/4 |
|
|
1.27 |
20 |
|
|
|
2分 |
| 7.00 |
(M7) |
1.0 |
|
|
|
|
|
|
|
| 7.00 |
(M7) |
|
0.75 |
|
|
|
|
|
|
| 7.00 |
(M7) |
|
0.5 |
|
|
|
|
|
|
| 7.72 |
G 1/16 |
|
|
0.91 |
|
|
|
28 |
|
| 7.90 |
5/16 |
|
|
1.41 |
|
18 |
|
|
|
| 7.90 |
5/16 |
|
|
1.06 |
|
|
24 |
|
|
| 7.94 |
5/16 |
|
|
1.41 |
18 |
|
|
|
2分5厘 |
| 8.00 |
M8 |
1.25 |
|
|
|
|
|
|
|
| 8.00 |
M8 |
|
1.0 |
|
|
|
|
|
|
| 8.00 |
M8 |
|
0.75 |
|
|
|
|
|
|
| 8.00 |
M8 |
|
0.5 |
|
|
|
|
|
|
| 9.00 |
(M9) |
1.25 |
|
|
|
|
|
|
|
| 9.00 |
(M9) |
|
1.0 |
|
|
|
|
|
|
| 9.00 |
(M9) |
|
0.75 |
|
|
|
|
|
|
| 9.00 |
(M9) |
|
0.5 |
|
|
|
|
|
|
| 9.49 |
3/8 |
|
|
1.59 |
|
16 |
|
|
|
| 9.49 |
3/8 |
|
|
1.06 |
|
|
24 |
|
|
| 9.53 |
3/8 |
|
|
1.59 |
16 |
|
|
|
3分 |
| 9.73 |
G 1/8 |
|
|
0.91 |
|
|
|
28 |
|
| 10.00 |
M10 |
1.5 |
|
|
|
|
|
|
|
| 10.00 |
M10 |
|
1.25 |
|
|
|
|
|
|
| 10.00 |
M10 |
|
1.0 |
|
|
|
|
|
|
| 10.00 |
M10 |
|
0.75 |
|
|
|
|
|
|
| 10.00 |
M10 |
|
0.5 |
|
|
|
|
|
|
| 11.00 |
(M11) |
1.5 |
|
|
|
|
|
|
|
| 11.00 |
(M11) |
|
1.0 |
|
|
|
|
|
|
| 11.00 |
(M11) |
|
1.25 |
|
|
|
|
|
|
| 11.00 |
(M11) |
|
0.75 |
|
|
|
|
|
|
| 11.00 |
(M11) |
|
0.5 |
|
|
|
|
|
|
| 11.07 |
7/16 |
|
|
1.81 |
|
14 |
|
|
|
| 11.07 |
7/16 |
|
|
1.27 |
|
|
20 |
|
|
| 11.11 |
7/16 |
|
|
1.81 |
14 |
|
|
|
3分5厘 |
| 12.00 |
M12 |
1.75 |
|
|
|
|
|
|
|
| 12.00 |
M12 |
|
1.25 |
|
|
|
|
|
|
| 12.00 |
M12 |
|
1.5 |
|
|
|
|
|
|
| 12.00 |
M12 |
|
1.0 |
|
|
|
|
|
|
| 12.00 |
M12 |
|
0.5 |
|
|
|
|
|
|
| 12.66 |
1/2 |
|
|
1.95 |
|
13 |
|
|
|
| 12.66 |
1/2 |
|
|
1.27 |
|
|
20 |
|
|
| 12.70 |
1/2 |
|
|
2.12 |
12 |
|
|
|
4分 |
| 13.00 |
(M13) |
|
1.5 |
|
|
|
|
|
|
| 13.00 |
(M13) |
|
1.0 |
|
|
|
|
|
|
| 13.00 |
(M13) |
|
0.5 |
|
|
|
|
|
|
| 13.16 |
G 1/4 |
|
|
1.34 |
|
|
|
19 |
|
| 14.00 |
M14 |
2.0 |
|
|
|
|
|
|
|
| 14.00 |
M14 |
|
1.5 |
|
|
|
|
|
|
| 14.00 |
M14 |
|
1.0 |
|
|
|
|
|
|
| 14.00 |
M14 |
|
0.5 |
|
|
|
|
|
|
| 14.24 |
9/16 |
|
|
2.12 |
|
12 |
|
|
|
| 14.24 |
9/16 |
|
|
1.41 |
|
|
18 |
|
|
| 14.29 |
( 9/16) |
|
|
2.12 |
12 |
|
|
|
4分5厘 |
| 15.00 |
(M15) |
|
1.0 |
|
|
|
|
|
|
| 15.00 |
(M15) |
|
0.5 |
|
|
|
|
|
|
| 15.83 |
5/8 |
|
|
2.31 |
|
11 |
|
|
|
| 15.83 |
5/8 |
|
|
1.41 |
|
|
18 |
|
|
| 15.88 |
5/8 |
|
|
2.31 |
11 |
|
|
|
5分 |
| 16.00 |
M16 |
2.0 |
|
|
|
|
|
|
|
| 16.00 |
M16 |
|
1.5 |
|
|
|
|
|
|
| 16.00 |
M16 |
|
1.0 |
|
|
|
|
|
|
| 16.00 |
M16 |
|
0.5 |
|
|
|
|
|
|
| 16.66 |
G 3/8 |
|
|
1.34 |
|
|
|
19 |
|
| 17.00 |
(M17) |
|
1.5 |
|
|
|
|
|
|
| 17.00 |
(M17) |
|
1.0 |
|
|
|
|
|
|
| 18.00 |
M18 |
2.5 |
|
|
|
|
|
|
|
| 18.00 |
M18 |
|
1.5 |
|
|
|
|
|
|
| 18.00 |
M18 |
|
2.0 |
|
|
|
|
|
|
| 18.00 |
M18 |
|
1.0 |
|
|
|
|
|
|
| 18.00 |
M18 |
|
0.5 |
|
|
|
|
|
|
| 19.00 |
3/4 |
|
|
|
|
10 |
|
|
|
| 19.00 |
3/4 |
|
|
|
|
|
16 |
|
|
| 19.05 |
3/4 |
|
|
2.54 |
10 |
|
|
|
6分 |
| 20.00 |
M20 |
2.5 |
|
|
|
|
|
|
|
| 20.00 |
M20 |
|
1.5 |
|
|
|
|
|
|
| 20.00 |
M20 |
|
2.0 |
|
|
|
|
|
|
| 20.00 |
M20 |
|
1.0 |
|
|
|
|
|
|
| 20.00 |
M20 |
|
0.5 |
|
|
|
|
|
|
| 20.96 |
G 1/2 |
|
|
1.81 |
|
|
|
14 |
|
| 22.00 |
M22 |
2.5 |
|
|
|
|
|
|
|
| 22.00 |
M22 |
|
1.5 |
|
|
|
|
|
|
| 22.00 |
M22 |
|
2.0 |
|
|
|
|
|
|
| 22.00 |
M22 |
|
1.0 |
|
|
|
|
|
|
| 22.00 |
M22 |
|
0.5 |
|
|
|
|
|
|
| 22.20 |
7/8 |
|
|
|
|
9 |
|
|
|
| 22.20 |
7/8 |
|
|
|
|
|
14 |
|
|
| 22.23 |
7/8 |
|
|
2.82 |
9 |
|
|
|
7分 |
| 22.91 |
G 5/8 |
|
|
1.81 |
|
|
|
14 |
|
| 24.00 |
M24 |
3.0 |
|
|
|
|
|
|
|
| 24.00 |
M24 |
|
1.5 |
|
|
|
|
|
|
| 24.00 |
M24 |
|
2.0 |
|
|
|
|
|
|
| 24.00 |
M24 |
|
1.0 |
|
|
|
|
|
|
| 24.00 |
M24 |
|
0.5 |
|
|
|
|
|
|
| 25.00 |
(M25) |
|
2.0 |
|
|
|
|
|
|
| 25.00 |
(M25) |
|
1.5 |
|
|
|
|
|
|
| 25.00 |
(M25) |
|
1.0 |
|
|
|
|
|
|
| 25.40 |
1 |
|
|
|
|
8 |
|
|
|
| 25.40 |
1” |
|
|
3.18 |
8 |
|
|
|
1吋 |
| 26.00 |
(M26) |
|
2.0 |
|
|
|
|
|
|
| 26.00 |
(M26) |
|
1.5 |
|
|
|
|
|
|
| 26.00 |
(M26) |
|
1.0 |
|
|
|
|
|
|
| 26.44 |
G 3/4 |
|
|
1.81 |
|
|
|
14 |
|
| 27.00 |
M27 |
3.0 |
|
|
|
|
|
|
|
| 27.00 |
M27 |
|
2.0 |
|
|
|
|
|
|
| 27.00 |
M27 |
|
1.5 |
|
|
|
|
|
|
| 27.00 |
M27 |
|
1.0 |
|
|
|
|
|
|
| 28.00 |
(M28) |
|
2.0 |
|
|
|
|
|
|
| 28.00 |
(M28) |
|
1.5 |
|
|
|
|
|
|
| 28.00 |
(M28) |
|
1.0 |
|
|
|
|
|
|
| 28.58 |
1-1/8 |
|
|
3.63 |
7 |
|
|
|
1吋1分 |
| 30.00 |
M30 |
3.5 |
|
|
|
|
|
|
|
| 30.00 |
M30 |
|
2.0 |
|
|
|
|
|
|
| 30.00 |
M30 |
|
3.0 |
|
|
|
|
|
|
| 30.00 |
M30 |
|
1.5 |
|
|
|
|
|
|
| 30.00 |
M30 |
|
1.0 |
|
|
|
|
|
|
| 30.20 |
G 7/8 |
|
|
1.81 |
|
|
|
14 |
|
| 31.75 |
1-1/4 |
|
|
3.63 |
7 |
|
|
|
1吋2分 |
| 32.00 |
(M32) |
|
2.0 |
|
|
|
|
|
|
| 32.00 |
(M32) |
|
1.5 |
|
|
|
|
|
|
| 33.00 |
M33 |
3.5 |
|
|
|
|
|
|
|
| 33.00 |
M33 |
|
2.0 |
|
|
|
|
|
|
| 33.00 |
M33 |
|
3.0 |
|
|
|
|
|
|
| 33.00 |
M33 |
|
1.5 |
|
|
|
|
|
|
| 33.25 |
G 1 |
|
|
2.31 |
|
|
|
11 |
|
| 34.93 |
1-3/8 |
|
|
4.23 |
6 |
|
|
|
1吋3分 |
| 36.00 |
M36 |
4.0 |
|
|
|
|
|
|
|
| 36.00 |
M36 |
|
3.0 |
|
|
|
|
|
|
| 38.10 |
1-1/2 |
|
|
4.23 |
6 |
|
|
|
1吋半 |
| 39.00 |
M39 |
4.0 |
|
|
|
|
|
|
|
| 39.00 |
M39 |
|
3.0 |
|
|
|
|
|
|
| 41.28 |
1-5/8 |
|
|
5.08 |
5 |
|
|
|
1吋5分 |
| 42.00 |
M42 |
4.5 |
|
|
|
|
|
|
|
| 42.00 |
M42 |
|
4.0 |
|
|
|
|
|
|
| 44.45 |
1-3/4 |
|
|
5.08 |
5 |
|
|
|
1吋6分 |
| 45.00 |
M45 |
4.5 |
|
|
|
|
|
|
|
| 45.00 |
M45 |
|
4.0 |
|
|
|
|
|
|
| 47.63 |
1-7/8 |
|
|
5.64 |
4-1/2 |
|
|
|
1吋7分 |
| 48.00 |
M48 |
5.0 |
|
|
|
|
|
|
|
| 48.00 |
M48 |
|
4.0 |
|
|
|
|
|
|
| 50.80 |
2” |
|
|
5.64 |
4-1/2 |
|
|
|
2吋 |
| 52.00 |
M52 |
5.0 |
|
|
|
|
|
|
|
| 52.00 |
M52 |
|
4.0 |
|
|
|
|
|
|
| 56.00 |
M56 |
5.5 |
|
|
|
|
|
|
|
| 56.00 |
M56 |
|
4.0 |
|
|
|
|
|
|
| 57.15 |
2-1/4 |
|
|
6.35 |
4 |
|
|
|
2吋2分 |
| 60.00 |
M60 |
5.5 |
|
|
|
|
|
|
|
| 60.00 |
M60 |
|
4.0 |
|
|
|
|
|
|
| 63.50 |
2-1/2 |
|
|
6.35 |
4 |
|
|
|
2吋半 |
| 64.00 |
M64 |
6.0 |
|
|
|
|
|
|
|
| 64.00 |
M64 |
|
4.0 |
|
|
|
|
|
|
| 68.00 |
M68 |
6.0 |
|
|
|
|
|
|
|
| 68.00 |
M68 |
|
4.0 |
|
|
|
|
|
|
| 76.20 |
3” |
|
|
7.26 |
3-1/2 |
|
|
|
3吋 |
| 101.60 |
4” |
|
|
8.47 |
3 |
|
|
|
4吋 |
| 127.00 |
5” |
|
|
9.24 |
2-3/4 |
|
|
|
5吋 |
|
 |
 |