CHECK OUT WHY DO TOOLS HAVE DROP FORGED STAMPED ON THEM !!

We see the words "drop forged" stamped on so many tools -- it makes us wonder what it is! Why do manufacturers want you to know that a tool is drop forged?

Striking a piece of hot metal with a hammer is forging, and blacksmiths have been doing this for centuries. As blacksmiths experimented with new techniques, they learned that complex shapes could be created by hammering metal into a die. The die contains the shape of the finished product. Modern manufacturers use either a falling hammer or a powered hammer to do the hammering (rather than doing it by hand), and usually use dies on both sides of the piece. This is drop forging.

Drop forging is a metal shaping process, the metal to be formed is first heated then shaped by forcing it into the contours of a die, this force can be in excess of 2000 tons. The drop forging process can be performed with the material at various temperatures;

• >Hot Forging
  During hot forging the metals are heated to above their recrystallization temperature. The main benefit of this hot forging is that work hardening is prevented due to the recrystallization of the metal as it begins to cool.
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• >Cold Forging
  Cold Forging is generally performed with metal at room temperature below the the recrystallization temperature. Cold forging typically work hardens the metal.

The reason why manufacturers want you to know that a tool is drop forged is because this tells you something about the strength and durability of the tool. The other two ways to make a tool would be casting it from molten metal or machining it (cutting material away) from a larger block of metal. The advantage of forging is that it improves the strength of the metal by aligning and stretching the grain structure. A forged part will normally be stronger than a casting or a machined piece.

CHECK OUT WHY DO SOME FORMULA 1 TYRES HAVE NO TREAD ON THEM !!

When you take the car for an MOT, one of the things they have to check for is the depth of tread left on your tyres. Anything below 1.6 millimetres is not allowed and can affect your breaking distance.

So why are some Formula 1 car tyres completely smooth?

The job of a tyre is to grip on to the road surface. Because the tyre is made of a very ‘grippy’ material there is a lot of friction between the tyre and the road. Friction is a very useful force that can slow you down and stop you slipping all over the place. Some Formula 1 cars use completely smooth tyres in dry weather. A completely smooth tyre has lots of contact between the rubber and the road so these smooth tyres give great grip for fast corners.

When you’re driving around in your hatchback in city, you can’t pull in at a pit-stop to have your tyres changed when the clouds open, so normal cars need tyres that can grip in all weathers. The tread patterns on the rubber do not help with grip, but are there to channel water off the road. If you let your tread get too shallow, the water can’t go anywhere and the wheels can skim along over the surface of the water. This is called ‘aquaplaning’ and is nasty for a car on any road, but could be much worse for a Formula 1 driver because of the speeds that they drive. So they can choose from a whole range of tyres to use during a race depending on the weather. Dry weather races are usually faster and more exciting because of the extra grip the smooth tyres can give on the race track.

WHY WIND TURBINES HAVE 3 BLADES? WHY NOT 2 OR 4??

Like many design considerations, the number of blades on a wind turbine is a compromise. Each blade disturbs the air for the following blade, so ideally you want as few blades as possible to maximize efficiency.

If you've ever had the chance to watch a wind turbine start, you would have noticed that the blades start rotating very slowly and then begin accelerating faster and faster. This is because of the aerodynamic design of the blades.

The more blades there are on a wind turbine, the higher will be the torque (the force that creates rotation) and the slower the rotational speed (because of the increased drag caused by wind flow resistance). But turbines used for generating electricity need to operate at high speeds, and actually don't need much torque. So, the fewer the number of blades, the better suited the system is for producing power.

ONE BLADED TURBINE :

Theoretically, a one-bladed turbine is the most aerodynamically efficient configuration. However, it is not very practical because of stability problems. 

TWO BLADED TURBINE :

Turbines with two blades offer the next best design, but are affected by a wobbling phenomenon similar to gyroscopic precession.(gyroscopic precession is the phenomenon in which the axis of a spinning object describes a cone in space when an external torque is applied to it.)

Also in case of 2 bladed turbine,since a wind turbine must always face into the wind, the blades will have to change their direction vertically when there is a shift in wind direction.2 bladed turbine will become completely vertical and completely horizontal once in a rotation.This will result in vibrations.

THREE BLADED TURBINE :

On the other hand, a turbine with three blades has very little vibration or chatter. This is because when one blade is in the horizontal position, its resistance to the yaw force is counter-balanced by the two other blades. So, a three-bladed turbine represents the best combination of high rotational speed and minimum stress.

The more blades you add to the system, the more the cost of producing it. This may seem obvious, but every pound counts when you are trying to produce energy from a turbine, and going to a 4 turbine system is going to cost more to produce.