Center Drill Bit is also known as Slocombe Drills, Centre Drills were originally designed to create the countersink required to locate a tailstock centre when turning between centres. They have a point angle of 60° to match the angle of a Tailstock Centre.
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Insulation of the skin with hand, fade, word quality. Refers to rubbing the insulation sheath with your fingers. Some poorly insulated wire sheaths are easy to discolor. This is especially true with red lines. After the rubbing, the skin color on the fingers or the word printed on the skin is rubbed off. It is generally a poor quality line.
Then use a fingernail and a squatting line to draw down and peel off the skin. It refers to the use of fingernails and enamels to insulate the skin. It is generally a poor quality line that can be drawn down and smashed down.
Repeatedly bend the insulated wire and break it three to four times. Refers to the repeated bending of the insulated wire, poor quality of the general poor insulation material, after bending 3 to 4 times after the insulation layer will break.
Use fire to ignite the wire and leave the open flame for self-ignition. It refers to the ignition of the insulating layer, and it is the inferior line that can spontaneously ignite after leaving the open flame.
The core is usually made of aluminum and copper, and the color is dark and light. Refers to the color of the core. The color of the inferior line is dark and has no metallic luster.
Fine inner diameter and outer diameter, look at the weight of leather. Means that if the above six methods can not be determined, you can also measure the outer diameter of the insulated wire and core diameter, the allowable error is ± 10%, if the measured value exceeds the allowable error, basically a poor quality insulated cable.
A Centre Drill can also be used to provide a start location for a drill when drilling down the centre of a bar held in a Lathe chuck. Centre Drills are short and rigid enough to mark the bar centre without wandering off if they are carefully offered up to a rotating work-piece.
How to identify the true and false of wire and cable
Take a closer look at the label printing samples. The address of the handwriting is unknown. Refers to the label on the label and the insulating cover. If there is a typo or a different shade of printing or the words are blurred, you must pay attention to it.