Under what circumstances should the center hole be punched, and what is the purpose of the center ho

First, the center hole you said should be the tip hole. Usually at one or both ends of the shaft.

2. At present, there are three forms: taper hole & two-layer taper hole, taper hole & two-layer taper hole + thread, taper hole & two-layer taper hole + threaded hole + precision blind hole. And all have certain standard dimensions and dimensional tolerances.

In the normal case, it is equipped with concentricity.

or the datum position of concentricity.

3. In fact, it is a process hole, which is used in processing, and is used for detection when the shaft is actually assembled, and it is generally not used in function.

Fourth, specifically, when the car is processing, one end is stuck with three grabs, and one end is pressed with the tailstock of the lathe, and it is not easy to jump when the car is made. The angle of the taper hole is matched with the angle of the tailstock of the lathe, generally 60 degrees is called A-hole, and there are also two sections, one is 60 degrees, and then a 120-degree one, which is called B-hole. Obviously, the B-shaped hole should be compatible with more tailstocks.

In this case, one taper or two taper holes will do.

Purpose: 1. When machining shaft parts, two center holes are generally used as positioning references.

2. When machining the outer circle, the two end faces and the center hole of the shaft are always processed first, and the preparation of the subsequent processing process is used as the positioning reference.

3. The design datum of each outer circle, taper hole, thread and other surfaces of shaft parts is generally the center line of the shaft, so the selection of two center holes is in line with the principle of datum coincidence, and the processing can achieve high mutual position accuracy, and the workpiece clamping is convenient.

1. In the mechanical structure, generally the important shaft end has a [center hole], and the [center hole] is also divided into A, B, C, D types, which is the [benchmark] of processing, which is very important.

2. [Center hole] is a standard term, and [thimble hole] is a popular term, which refers to the same thing, just like [motor] and [motor].

3. In addition, [thimble] also includes: [live thimble] and [dead thimble], when processing parts, [thimble] is inserted in the [thimble hole].

In die-casting, the product is in the mold, just like plasticine in a bottle, and it is taken out to be topped with a "small stick", and the top stick is called a "thimble";

The traces of the thimble on the product are called "thimble traces";

The hole where the thimble is installed on the mold is called the "thimble hole";

The thimble hole and the center hole have nothing to do with it!

The center hole is used as a process benchmark, which is generally used for the clamping, inspection and assembly positioning of the workpiece; The axial dimensions in CNC axis machining are programmed and manually positioned.