If you do your own drilling and tapping, you quite often haven't got the tapping drill in with the taps.
An easy way to work it out is to subtract the pitch figure of the tap from the tap size.
It works on coar$e (bloody banned words!) and fine threads.
It saves running to the books with greasy paws.
I've listed some here and you can see how it works.
Apologies if this is boring (Joke?)
METRIC COAR$E SIZES
----------------------------
TAP DRILL
SIZE SIZE
----------------------------
1mm x .25 0.75mm
1.1 x .25 0.85
1.2 x .25 0.95
1.4 x .3 1.1
1.6 x .35 1.25
1.7 x .35 1.3
1.8 x .35 1.45
2 x .4 1.6
2.2 x .45 1.75
2.5 x .45 2.05
3 x .5 2.5
3.5 x .6 2.9
4 x .7 3.3
4.5 x .75 3.7
5 x .8 4.2
6 x 1 5
7 x 1 6
8 x 1.25 6.8
9 x 1.25 7.8
10 x 1.5 8.5
11 x 1.5 9.5
12 x 1.75 10.2
14 x 2 12
16 x 2 14
18 x 2.5 15.5
20 x 2.5 17.5
22 x 2.5 19.5
24 x 3 21
27 x 3 24
30 x 3.5 26.5
33 x 3.5 29.5
36 x 4 32
39 x 4 35
----------------------------
METRIC FINE SIZES
----------------------------
TAP DRILL
SIZE SIZE
----------------------------
4 mm x .35 3.6mm
4 x .5 3.5
5 x .5 4.5
6 x .5 5.5
6 x .75 5.25
7 x .75 6.25
8 x .5 7
8 x .75 7.25
8 x 1 7
9 x 1 8
10 x .75 9.25
10 x 1 9
10 x 1.25 8.8
11 x 1 10
12 x .75 11.25
12 x 1 11
12 x 1.5 10.5
14 x 1 13
14 x 1.25 12.8
14 x 1.5 12.5
16 x 1 15
16 x 1.5 14.5
18 x 1 17
18 x 2 16
20 x 1 19
20 x 1.5 18.5
20 x 2 18
----------------------------
If you are using a Helicoil they label tap sizes different but they are not special taps.
To install say,an m10 x 1.25 helicoil use tap size m12x1.25,to install m8 1.25 helicoil use a m10x1.25 tap.
You can make up your own insertion tools and it save paying those astrnomical prices for helicoil kits.
The drill sizes for the Helicoils are:
Helicoil Drill
M3.5x0.6 #26
M3x0.5 1/8
M4x0.7 #19
M5x0.8 #4
M6x1 1/4
M7x1 L
M8x1.25 Q
M10x1.5 Z
M12x1.75 1/2
M14x2 37/64
M16x2 21/32
M18x2.5 47/64
M20x2.5 13/16
|
|
Don't know if you know this but.... by 'Andrewrr' << You are here!
