Forms of the center holes
It is enough to demonstrate the central drill in kind, distributing them to students for consideration. From students we can expect an independent analysis of the elements of the center drill and the principles of its work; It is only necessary to dwell on the features of central drill centers, requiring a very sensitive supply when drilling the Channel of the Central hole. In construction, you may need bulk polymer floors the price of which you can look here.
It is advisable to show central flocks in kind in the workshop and there to explain the principle of their work there. In the absence of such machines, you can use the poster.
It is advisable to demonstrate the impact of the irregular shape of the central holes on the quality of processing on the details, rejected on the latest operations due to improper centering. It must also be emphasized that improper centering is influenced not only on the quality of the manufactured fly, but also on the safety and accuracy of the machine centers.
At the very beginning, it is necessary to establish a connection with the previous topic (drilling and drilling) with several questions. Questions are selected so as to emphasize the deficiencies in processing holes with drilling.
1. With what accuracy you can process holes by drilling?
2. What is the largest diameter of the hole can be obtained by drilling?
3. What is the cleanliness of the surface of the hole treated with drilling?
Having received answers to questions, the teacher leads the students to the conclusion that in cases where the exact size of the hole is required, the high purity of the surface of the hole, and also when processing the holes of the large diameter, a new type of processing is necessary. This type of processing is melting. Having described the melting operation, the teacher proceeds to the consideration of boring incisors.
Incisors must be shown in kind.