Unlike most commonly used turning, milling and drilling tools, the cutting edge and the opposite surface of the thread tapping are relatively weak, and the cutting edge is prone to collapse or crack, especially when processing steel materials。
Therefore,let’s learn 10 tips for thread tapping in precision machining.
1. The hole of the bottom hole of the thread on the workpiece should be chamfered,both ends of the thru thread hole should be chamfered.
2. The position of the workpiece clamp should be correct, try to make the centerline of the threaded hole placed in a horizontal or correct position, so that the tapping can easily judge whether the tap size is perpendicular to the plane of the workpiece.
3. At the beginning of tapping, try to put the tap straight, and carefully check and correct the position of the tap.
4. When tapping, every 1 / 2-1 turn of the tapping, it should rotate about 1/2 turn, so that the swarf can be easily discharged.
5. When tapping blind thread holes,to drop out the tap and remove the swarf in the hole.
6. When tapping the screw holes of plastic materials, lubricating coolant should be added. For steel materials, motor oil or concentration-bound emulsions are generally used.
7. When changing the screw tap during the tapping process, you must first screw into the thread hole by hand. When you can no longer screw in, continue to tap. When the tapping is completed, it is best to drop out it by hand to ensure that the quality of the tapped thread is not affected.
8. When tapping by machine,the screw tap and thread hole should be kept coaxial.
9. When tapping by machine,the calibration part of the tap cannot be all over, otherwise,it will produce messy teeth when the tap is dropped out.
10. When tapping by machine, the cutting speed is 6-15m/ min for general steel, 5-10m/min for quenched and tempered steel,2-7m/min for stainless steel,8m/min for cast iron.
