HAMMER-THE MAGICIAN

In my experience that after the publication in the journal “modelist-Konstruktor” home-made car (like mine in the January number for 1971) are the authors of many cities requesting them to share their own experiences. Now, during the crisis, when the possibility of homebrew is limited, I want to help interested readers advice: how, in practice, to restore or to produce the car body with the method of knockout.

Willing to do it for anyone needing such assistance, especially that in the pages of technical journals to this time almost nothing like that might help Amateur drivers realize the metal in your imagination a way of squeezing sheet metal.

 

Of course, the drift is largely inferior to the stamping or Vileika, but the hammer helps in conditions of Amateur design: they can be manufactured, for example, the wing of the machine so that and experienced in such matters can doubt that it was done solely with a hammer.

Imagine the middle ages: shields and helmets, knight armor, armor — they are obviously done nothing other than hammers. And it is strange that in our time the crowd around the handcrafted and argue among themselves, and sometimes the author argue that it is impossible to do with a hammer, and is only available to industrial stamp.

 

Work on the drift requires a relatively small snap — set tools and simple devices. A lot more will require prior thought. And it’s my job to try to help beginners, to guide them on the correct path.

 

 

 

 

Fig. 2. Strikes the side face of the square hammer

 

 

 

 

Fig. 4. Methods of manufacture of the trough (radii indicate the degree of curvature of the metal of the PA under the hammer blows in the increasing directions)

 

 

Fig. 5. The direction of impact for obtaining the splash guard (with different radii)

 

Start with the hammer. Consider the behavior of the metal sheet at specific levels of impact and depending on the shape of the firing pin tool. This is evident in the manufacture of the simplest curvilinear forms. And as you know, the complex consists of simple parts and, for example, a complicated shape of the wing is a combination of the same simple shapes that will be considered below.

 

Figure 1 shows the line of impact across the strip. The stretching of the metal occurs along it. This property is used, for example, when the spacing of the spit, where unacceptable stretching along its blade, otherwise it will meander on the canvas of the spit.

 

This way you can lengthen the strip and striking at one side to bend it into a ring, to produce a complex decorative plate and other such things.

 

Figure 2 demonstrates the same effect even if the strikes are not the toe, and the side face of the square hammer. Indispensable here is a square 500 — 600 gram hammer.

However, the tool can be more complex shapes. Figure 3 shows a special mednitskii hammer. Its damage blows stretch the material radially from the center of the workpiece to the periphery. This tool is suitable for the knockout spherical surfaces — as, for example, bowl, ball surface, the extreme section of the buffer. And on the flat surfaces (hood) this hammer will make unwanted blistering, excessive work hardening of the metal.

 

In all cases we must strive to the radius of the firing pin is closer to the radius of the part. Figure 4 shows the process of obtaining a bent gutter. The length of the arrows represents the degree of stretching of the metal. When squeezing, first smooth bend middle, with a big bend (or otherwise smaller R3), since the stretching of the sides (R2) it will partially crack. Board of the trough is a large arc, hence, requires more stretching, with the “damping” of the shock to R1. Such details as the mudguard is the same trough, only by bending in the opposite direction (Fig. 5). The workpiece is bent less, because when stretching along the axis of its side compressed. This figure is more time-consuming, and the metal gets more hardening — disturbed internal structure, making the material weaker. Therefore, strive to shocks, especially sharp striker, was weak and lay close to each other. In this case, all the portions of the sheet are subjected to stretching, and thereby the metal gets rid of peretolchina.

 

 

Fig. 6. Techniques squeezing in the manufacture of complex segment shapes (“pot”):

 

1 —the direction of impact for the transverse stretching of the metal; 2—the same for longitudinal stretching on both sides

 

 

Fig. 7. Getting a flare on the wing of the car

 

 

 

 

 

 

Fig. 10. Getting sharp edges with a mallet (A—initial drift, B—treatment after the coup and shift of the sheet)

 

Figure 6 shows a diagram of the squeezing of the segment “pot” (without a bottom). It consists of two previously discussed figures. In the manufacture of smooth cutting is taken and extracts Mednick hammer on a smooth plate. Then pass chute (lower) part of the techniques discussed for figure 4. And so, passing from one section to the other, watching the forming segment.

 

It happens that the detail of the lead screw. It “POPs” due to internal stresses. But do not be upset and continue to follow a common format, presenting it straightened. Next is “palpated” a hammer on the area that needs stretching, and if the item begins to grow and warp, that there is need to continue to beat. Having experience without “probing” to determine such places.