Many manufacturing processes involve heat that is created by burning coal or oil.
Right- and left-handed screw threads The right-hand rule of screw threads The helix of a thread can twist in two possible directions, which is known as handedness. Most threads are oriented so that the threaded item, when seen from a point of view on the axis through the center of the helix, moves away from the viewer when it is turned in a clockwise direction, and moves towards the viewer when it is turned counterclockwise.
This is known as a right-handed RH thread, because it follows the right hand grip rule. Threads oriented in the opposite direction are known as left-handed LH. By common convention, right-handedness is the default handedness for screw threads.
Therefore, most threaded parts and fasteners have right-handed threads. Left-handed thread applications include: Where the rotation of a shaft would cause a conventional right-handed nut to loosen rather than to tighten due to applied torque or to fretting induced precession.
The left-hand grinding wheel on a bench grinder. The axle nuts, or less commonly, lug nuts on the left side of some automobiles. The securing nut on some circular saw blades - the large torque at startup should tend to tighten the nut.
The spindle on brushcutter and line trimmer heads, so that the torque tends to tighten rather than loosen the connection In combination with right-hand threads in turnbuckles and clamping studs.
In gas welding the flammable gas supply uses left-handed threads, while the oxygen supply if there is one has a conventional thread The POL valve for LPG cylinders In a situation where neither threaded pipe end can be rotated to tighten or loosen the joint e.
In such a case, the coupling will have one right-handed and one left-handed thread. In some instances, for example early ballpoint pensto provide a "secret" method of disassembly. In mechanisms to give a more intuitive action as: The leadscrew of the cross slide of a lathe to cause the cross slide to move away from the operator when the leadscrew is turned clockwise.
The depth of cut screw of a "Bailey" or "Stanley-Bailey" type metal plane tool for the blade to move in the direction of a regulating right hand finger. Some Edison base lamps and fittings such as those formerly used on the New York City Subway have a left-hand thread to deter theft, since they cannot be used in other light fixtures.
It may be squaretriangulartrapezoidalor other shapes. The terms form and threadform sometimes refer to all design aspects taken together cross-sectional shape, pitch, and diameters.
Most triangular threadforms are based on an isosceles triangle.
These are usually called V-threads or vee-threads because of the shape of the letter V. For buttress threadsthe triangle is scalene. The theoretical triangle is usually truncated to varying degrees that is, the tip of the triangle is cut short.
A V-thread in which there is no truncation or a minuscule amount considered negligible is called a sharp V-thread. Truncation occurs and is codified in standards for practical reasons—the thread-cutting or thread-forming tool cannot practically have a perfectly sharp point, and truncation is desirable anyway, because otherwise: The cutting or forming tool's edge will break too easily; The part or fastener's thread crests will have burrs upon cutting, and will be too susceptible to additional future burring resulting from dents nicks ; The roots and crests of mating male and female threads need clearance to ensure that the sloped sides of the V meet properly despite a error in pitch diameter and b dirt and nick-induced burrs.
The point of the threadform adds little strength to the thread. In ball screwsthe male-female pairs have bearing balls in between. Roller screws use conventional thread forms and threaded rollers instead of balls.
Thread angle The included angle characteristic of the cross-sectional shape is often called the thread angle. For most V-threads, this is standardized as 60 degreesbut any angle can be used. The cross section to measure this angle lies on a plane which includes the axis of the cylinder or cone on which the thread is produced.
Lead, pitch, and starts[ edit ] Main article:You need to see more about aspects of coursework. An understanding and food technology is a level gcse textiles gcse science course, product design and textiles scheme of year coursework. Analysis, planning, a teaching research analysis and analysis every .
During the next two years you will be looking into a number of new design and manufacture techniques in the areas Textiles, Resistant Materials, Graphics and Systems and control as partr of your theory lessons which will be used in your end of year 11 exam (which is 50% of your GCSE) and in your coursework folder (which in also 50% of the GCSE).
A textile manufacturer is to introduce a range of jackets for physical fitness instructors and coaches to wear when working outdoors.
Danielle Andress (MFA ) is the fifth annual recipient of the Lia Cook Jacquard Residency. In her vibrantly boisterous hand woven work, Andress explores the relationship between textiles, narrative, and nostalgic artifact. CURRICULUM SUMMARY – Textiles YEAR 7 TERM 1 TERM 2 (1/2 term) CONTENT Design and Make a themed cushion: Students are given a design brief which requires them to research a . Mechatronics is a multidisciplinary engineering field that combines systems design, computer, electronic, mechanical, and control engineering.
The jacket should: • be unisex • be adaptable to changing weather conditions • remove the need for a bag Product disassembly. 1.
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Social, Moral and Environmental issues. Reuse - by designing for disassembly and recovering materials from 'end of life' products. Repair - products rather than replacing them. Refuse - to accept unethical or wasteful designs.
GCSE Textiles Coursework?.