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Spindle speed [min-1 ] = Vc (cutting speed) × 1000 ÷ DC (tool diameter) ÷ 3.14
Since the feed speed (= F) of the tap is 1 revolution and 1 pitch, the value obtained by multiplying the pitch of the above material by the rotation speed is calculated (mm / min).
You have now calculated the rotational speed and feed rate at which the tool is moving.
(3) Process the tap until it penetrates.
(4) Pull out the tap with reverse rotation
(5) Inspect using the gauge indicated in the drawing.
(6) If the gauge inspection passes, it is completed.
Precautions for point-to-tap processing
spiral pointed tap Precautions when using (1)
The problem with threading with spiral pointed tap is that chips do not leave the workpiece until the tap-bite part is completely penetrated.
If the spiral pointed tap is rotated backwards in the middle of the pilot hole, chips that leave the cutting part of the tap will remain connected to the workpiece.
In this situation, if the tap is reversed, chips that are still connected to the workpiece may bite into the tap, which may cause the chipping or screw of the tap to defect.
| It seems to have rotated in reverse without penetration | |
| During processing | In reverse rotation |
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| spiral pointed tap During machining, chips are discharged in the direction of tap travel. | Chips that are still connected to the workpiece are bitten when rotating in the opposite direction. |
spiral pointed tap Precautions when using (2)
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Check the length of the tap. If the pilot hole is pierced and the screw is halfway through, the tap is considered a blind hole |
| spiral fluted tap is recommended |
spiral pointed tap Precautions when using (3)
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spiral pointed tap Pull out at least chamfer +3 pitches |
| A: 3 pitches or more B: Feeding part |
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* The guideline for penetration is about the point groove that comes out.
If possible, it is a good idea to add a margin for chamfer +2 pitches or more, and penetrate the bite part +3 pitches or more.
At that time, depending on the size, external center is attached, so don't forget to add that amount.
Tapping depth = effective thread length + length with bite (incomplete thread length) + 3 pitches (margin for chip separation) + ( external center length)