Chris Johns
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What are the design principles for risers in sand casting?
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Casting terminology can vary a bit. My experience is in art casting in cast iron. In my experience with sand casting risers specifically tend to be used as vents to allow gas to escape from the ...

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Plumbing Imperial units confusion - 3/4" is supposed to be around 19mm, right?
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Yes it is BUT BSP (and pipe fittings in general) fittings are specified by the nominal bore rather than the thread diameter, which can be confusing if you are used to dealing with metric fasteners.

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Camera and light frequency rate
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There are a number of reasons why lights might flicker. Incandescent bulbs running on AC will, of course have a cyclical input although the fact that the filament stays hot tends to smooth the ...

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How can I measure the vibrations of a solid object?
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You might want to look at contact pickups designed for acoustic musical instruments. Try searching for contact microphones of contact transducers. These tend to be based on piezo electric devices ...

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Why regenerator "wheels" in a turbine engine?
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The main advantage of a rotary regenerator is that you can pack a lot more surface area into a given volume than with a shell and tube type device important for gas-gas heat exchange where heat ...

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What is the purpose of grid-like details on engine blocks?
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There are two closely related reasons. The first is that in terms of pure geometry webs tend to be more efficient in terms of strength and stiffness to weight ratios compared to a solid block of ...

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Can CO2 produce energy to drive a bot
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Potentially yes. There are a lot of homemade toys which use a reaction between vinegar and bicarbonate of soda to make simple CO2 jet engines. However if you want to use this sort of reaction to ...

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Friction clutch and the force required
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Clutches do indeed carry quite lot of force but when you pull away from stationary the correct technique is to use fairly low revs and blend the clutch in quickly but smoothly. In this case the clutch ...

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Which frame is optimal for children's bicycle trailers? tubular or rectangular frame and why?
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I assume that you are talking about a steel frame with a wooden body mounted on it. In general round tube is more efficient, but if the loading is primarily bending in one direction rectangular ...

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Are spring constant and rate constant the same thing?
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Spring rate can be specified either for a whole spring or per unit length which is often more convenient if you are buying spring stock to cut to length. The constant of a whole spring is force per ...

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How maps of globe, country or region were created few decades/centuries ago when modern technology like today did not exists?
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You don't need satellite images to make accurate maps. Accurate surveying techniques have been around for a very long time and are essentially based on fairy simple technology. The basic ...

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Correct term for non-countersunk flat hex screw/ bolt?
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3 votes

I would call that a wafer head machine screw.

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Can you perceive similar kind of "humanizing" of technology in other fields of engineering than computer science?
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An important factor is that computing inherently has a numbers of layers of abstraction and function between the end user and the actual functionality. To some extent this is a from of automation in ...

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Which materials can be used to make permanent casting molds for cast iron?
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You can cast iron into cast iron moulds as long as the moulds have plenty of mass compared to the quantity of metal you are pouring into them. Small artisan foundries sometimes use cast iron moulds to ...

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Can a Plasma Cutter use for melt metals?
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No. Plasma cutters use a jet of air along with the arc to cut they pretty thoroughly oxidise the metal, plus the jet would just spray molten metal everywhere if you tried to contain it. In terms of ...

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Non-Clutch Vehicle Drivetrain - How Does it Work?
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Conventional automatic transmissions have a torque converter which uses a viscous rather than a rigid coupling to connect input and output. This performs a similar function to a friction clutch but ...

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Controlled demolition of a sky scraper?
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It is certainly possible, although far from easy and requires very specialist knowledge. First the building will be surveyed in great detail to determine how the loads are carried throughout the ...

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How are single tube bicycles prevented from collapsing?
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While a single tube like that isn't as structurally efficient as a triangulated frame there is no reason it can't take the required loads as long as it is chunky enough. Note that, especially in the ...

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Why do we pave roads instead of making them from removable parts?
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Other answers have well described a road is a lot more than just the surface layer and the vast majority of the cost is the planning and logistics involved rather than the actual materials. Current ...

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Is a metal Prince Rupert's drop possible?
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Sort of. This is rendered a bit of a moot point as most metals already have the the sort of hardness and impact resistance that heat treating imparts on glass anyway so you are essentially ...

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Why does the Compressor Fan for an Air Conditioner need a Starter Capacitor?
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3 votes

The simple answer is that for a box fan the load on the motor is proportional to its speed so its starting torque is very low. In the case of a compressor the motor is working against significant ...

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Feedback on idea for a power station
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For pretty fundamental physical reasons any power generator is only a way of converting one sort of energy to another ie converting the energy you have available to the sort of energy that you want. ...

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Pouring aluminum into another block of Aluminum
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This is unlikely to work very well. The biggest issue is that you won't get good adhesion between the two surfaces. aluminium has a particularly resilient and inert surface oxide layer so molten ...

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How were 90 degree angles made?
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It is fairly easy to construct a pretty accurate right angle using a divider to bisect a straight line with the limiting factors on accuracy being the straightness of your lines and the consistency of ...

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Defining camera as a passive radar
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Not really. Firstly the RA in RADAR stands for RAdio which covers significantly longer wavelengths than the visible light (an in some cases near infra-red) which cameras can detect. While light ...

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Planned power outage and backup generator
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Electronics can be quite sensitive to the quality of the power supply, particularly in terms of providing a stable voltage and the right sort of AC waveform. There are two obvious solutions for ...

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Is it Possible to Automatically Transform an Image of an Object into a Line Drawing in AutoCAD?
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One option is to import the jpeg directly into AutoCad and simply trace the lines you want over the top in a new layer. While this isn't automatic as such I suspect that it may end up being less ...

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Is hardened steel better than tough steel?
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In steel hardness is closely related to tensile strength so a hardened steel will have both high hardness and high tensile strength. Toughness is a bit more difficult to quantify than strength but ...

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silicone injection molding - making a flexible ring
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3 votes

If you are using RTV silicone of the type used for prosthetics and animatronics then you can get a variety of grades with different mechanical properties, commonly rated by Shore Hardness. You can ...

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Are front wheel drive vehicles inherently flawed?
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There is no real general answer to this as the drive and handling characteristics will vary from vehicle to vehicle, depending particularly on weight distribution and suspension design. However the ...

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