You will need
- the spring wire of suitable diameter;
- gas torch cutting of metal;
- – locksmith tool;
- – heat or domestic oven.
Choose a material for the manufacture of springs. In production to do this, use special carbon and alloy steels or non-ferrous alloys – 65G, 60ХФА, 60S2A, 70СЗА, Br. B2, etc. With self-manufacturing products most appropriate material is another spring with a suitable wire diameter.
If the diameter does not exceed 1.5-2 mm, the spring can navit without heat treatment. To do this, straighten the wire so that it became completely flat, and wrap it on the mandrel.
The mandrel diameter should be smaller than the nominal inner diameter of the springs to compensate for the elastic deformation. May have to try several mandrels of different diameters to experiment to find the right size. The distance between the turns of the compression spring should be slightly larger than the finished product, and two outer coil should fit snugly to each other.
In that case, if the diameter of the wire of the original spring exceeds 2-2. 5 mm, before starting work, it should be annealed. Without this it is impossible to efficiently straighten and navit wire on the mandrel.
Annealing is best to use a special heat oven. If not, use a wood brick or metal. Melt the oven birch wood and put the spring into the resulting coals. Make sure that it became red-hot and leave to cool with the oven. After annealing wire become soft.
Straighten annealed the blank and wrap it in a frame, observing the same rules as in step 3. In the manufacture of a tension spring coils navigate close to each other.
Temper the spring. To do this, heat it to a temperature of 830-870°C and lower the spindle or transformer oil. Temperature control visually using the following information on the color of the heated metal. At the temperature of 800-830°C, the metal has a bright cherry red color at a temperature of 830-900°C – light red at a temperature of 900-1050°C – orange.
After hardening, compress the spring compression before complete closure of the coils and leave in this position for 20-40 hours. This operation will reduce the distance between the turns and bring it to nominal. Grind on grinding machine the ends of the spring for the flatness of its end faces.
When tempering for hot springs, you can use a gas burner. The latter can be used for heating during annealing, but in this case it is necessary somehow to provide the slow cooling of the product – at a rate of approximately 50-100°C/h.