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Archival Reviews of Shimano Road Headsets


SHIMANO HP-7400 "OLD" DURA-ACE HEADSET

Shimano's ultra light, high end Road Racing headset. The DA headset has cast aluminum upper, lower cups and head lock nut. Each of these parts, after being cast, is machined to their exquisite light weight final shape. The cup bottoms and tops, the seats for the steel races, and the threads for the head lock nut, are finished to the measured precision that a professional racer would want. The steel races are ground to the same precision. The fork cone race, which is subject to so much stress is titanium plated to add a harder surface. It uses twenty 4mm steel ball bearings in both steel retainers. This headset is triple sealed. There are seals between the cone and cup race surrounding the bearings to protect it from road contaminants and there is a stem seal in the head lock nut. This headset's stack height is 37mm and weighs 114 grams. It is made in the 1" size, with the English/Italian thread pattern, in Silver only. This headset was replaced by the 7410. We sold it for $79.99

SHIMANO HP-6400 "OLD" ULTEGRA HEADSET

This headset weighs just 99 grams! The fork cone race is cast of stainless steel with a smoothly ground bearing surface. The bearing cups are made of cast, then machined aluminum, with precisely ground steel races pressed into them. The upper cone race is cast of steel lightly machined then colored Black. The Ultegra head key washer is stamped of steel and recesses into the upper cup, to help prevent the upper cup from backing off. The head lock nut is forged aluminum, octagonally shaped, 32mm across. Twenty 4mm steel ball bearings are held in a steel retainer for both bearing sets. This is a triple sealed headset, featuring plastic seals between the cup and cone race with a stem seal (rubber washer) mounted on the head lock nut. This 1" headset is for Road Racing use, has a stack height of 33.5mm, and uses a 32mm headset wrench to tighten both the upper cup and head lock nut. This was replaced by the 6500 model. We sold it for $29.99





In-depth Information About Metals

Aluminum
Aluminum is extracted electrolytically from bauxite ore. It is made by the electrolysis of aluminum oxide which is found in larger concentrations within bauxite ore. Bauxite is a mixture of the hydroxides of aluminum, together with other impurities such as oxides of iron, titanium, and silicon. Bauxite is produced by the weathering and change of aluminum silicate rocks usually found in tropical and semitropical regions where climate has produced an accelerated weathering process. Bauxite is not a rare ore and is widely available in the US, the Caribbean, and Europe. Approximately 4 pounds of read the full article...

Beryllium
Beryllium is a specialty metal that is steel-grey metal in color, with an extremely low density, making it very light weight. At 1.85 grams to the cubic centimeter, its density compares to that of magnesium. It is also a high strength metal, making it possible to design light weight, thin membered parts with ahigh stiffness. A column made of beryllium to support a load placed directly downward on top of it, will have a greater load carrying capacity, and be lower in weight than any other metal of equal size.

Until the 1950's beryllium was used read the full article...

Titanium
The element titanium was discovered in 1763 by an English cleric, William Gregor who was an amateur chemist with an inquiring mind. It was in the black sands of Cornwall that he discovered the new element that had up to that time, attracted little scientific interest. A few years later, an Austrian, Klaproth, extracted the same element from an ore widely known as "rutile", which is a mineral consisting of titanium dioxide (one titanium atom, two oxygen atoms), that is a reddish-brown substance with a slight metallic luster. While rutile is the highest grade read the full article...

Metallurgic Hardness Testing
There are three types of tests used with accuracy by the metals industry,they are the Brinell hardness test, the Rockwell hardness test, and the Vickers hardness test. Hardness is the property of a metal which gives it the ability to resist being permanently deformed (bent, broken, or have its shape changed), when a load is applied. The greater the hardness of the metal, the greater resistance it has to deformation. Since the definitions of metallurgic ultimate strength and hardness are rather similar, it can generally be assumed read the full article...


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