Mechanical Engineering

# Roger A Bailey

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## Profile Information

• Engineering Qualification
B.Sc (hons)
• Year of completition
1999
• Name of Institute
University of West of England (UWE)

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1. ## Bearings for Shafts

There is nothing to stop you from using more than two bearings on one shaft, however, there is little poInt in doing so unless the shaft is subject to flexing caused by length, or its resonant frequency in operation which may cause vibration. If the shaft has diameters along its length greater than the end bearing diameter, or features that would prevent fitting a roller or ball bearing, then it would only be possible to fit split bearings in the middle such as that found on the 'big end' of an engine connecting rod.
2. ## Can anyone Make ktm duke swing arm model

Hi DrD. Hope you're well. As our friend Preetam indicated, The KTM 'Duke' is a trail bike (part on-road and part off-road) manufactured in Austria. The swing-arm is the pivoting, fork-shaped part of the rear suspension that the rear wheel is fastened to. The other end of the swing-arm pivots around a point close to the back of the engine. The shock absorber that takes care of the rear suspension is mounted between the frame and the swing-arm, compressing and rebounding as the swing-arm rotates about its pivot point.
3. ## L Bar Structural Question

You say that 6" of the angle iron will be buried into the concrete wall, so presumably 14" will be sticking out on which you will be fastening some item. This item will have a mass, in other words a force that is acting vertically downwards onto the metal protruding from the wall and producing a bending moment. In effect, this set-up is a cantilever. You will need to know the point along the protruding 14" at which this force will be acting, then, knowing the exact thickness of your L shaped angle iron, it should be possible to calculate which method of fixing the metal would be best. My own estimation is that the metal would be best set into the concrete like so - { L. }. In this way the direction of the downward force will be aligned with the vertical side of the metal and will be able to best resist the downward acting force.
4. ## Manufacturing Process

To answer your own question ask yourself what the component is going to be used for and what forces will it be subjected to? Castings can be made in many different and complex shapes whereas forgings are more limited regarding the shapes that they can be hammered into by either hand or machine. As already mentioned by a previous contributor, unfortunately castings are inherently brittle due to their grain structure. They offer virtually no elastic deformation and subsequently break with little warning when subjected to excessive pressure. Iron castings do however provide good wear resistance which is why the material is used for applications such as the cylinder blocks in car engines. Forgings, on the other hand, have excellent directional strength due to the way in which they are hammered into shape. This affords forged steel a high directional strength along the elongated line of its grain structure. Furthermore, forgings can be elastically deformed and, size for size, have a much higher ultimate tensile strength compared to cast iron. These are just a few of the ways in which castings differ when compared to forgings. Which method is better depends very much on the application they are to be subjected to.
5. ## Toyota corolla do not start after the engine was change the nozzle do open and it do spark,fuel line ok, immo ok. Pls what the cause and possible solution.

If you are satisfied that you have a good spark at the plugs and a strong battery, try pouring a small amount of neat fuel into each plug hole. Quickly replace the spark plugs and HT leads and crank the engine over with the ignition on. The motor should fire up for a short while. If it doesn't then the fuel isn't reaching the combustion chamber so check the fuel pump and lines.
6. ## Electromagnetic Engine

The solenoid you are using gets hot due to the frictional and magnetic resistance of your motor in start-up. Have you thought about introducing a slave motor to initiate the starting cycle?
7. ## Tricycle Axle

Actually Jay I misread your question. I thought I had read 'bicycle' when in fact you are building a tricycle. I presume you want to power the tricycle by using a brushless motor integrated into either one or both rear wheel hubs. With a tricycle layout it might just be possible that you could use a 3/8 axle, but you would need to extend the axle from where it exits the wheel into the frame support and then beyond the frame to a point where it would be reinforced by at least 3 supporting angled gussets (just as the roots of a tree reinforce the trunk in a wind). I would suggest your standard 3/8" axle is extended by at least 70% on top of its original length in order to resist the torque loading at the frame support point. If you want to do a proper job then refer to my first answer above and increase the cross-sectional area of support by installing a larger tubular axle.
8. ## Tricycle Axle

Dr D is quite correct Jay, You should be able to work out the static and dynamic loadings yourself if you're an engineer. If by some chance you're not then a good ploy is to look at other working systems that use a similar layout. You will see that when you replace two legs with one, all load-bearing components need to be 'beefed up' considerably. My own motorcycle for example (an MV Agusta) uses a single-sided swing arm instead of the more conventional swingarm with two legs. The loads imposed on it from transmitting power, braking, accelerating and holding the wheel in alignment are significantly higher than 50% of a two-leg set up. This is because the single-sided arm has to be additionally resilient to the inherent twisting force that it would be subjected to. A normal bicycle wheel has a spindle of 3/8" diameter. I would suggest you need at least a 1" diameter spindle but, like my motorcycle, it can be tubular in order to reduce overall weight.

11. ## Bevel Gears.jpg

Bevel gears are marvellous innovations of engingineering in changing directional rotation of a shaft. Straight cut bevel gears are relatively easy to produce but tend to be noisy in operation, whereas the helical bevel gears illustrated above reduce noise considerably but require precision end-float adjustment. Contrary to popular belief, gearing systems were not invented by man at all but evolved from nature. The plant hopping species of insect Issus coleoptratus utilises a gearing system (below) to synchonise its hind legs when jumping.
12. ## Which type of bearing is this?

This is a two-row, self-aligning spherical roller bearing, typically used for applications of heavy radial loading.
13. ## Differentiate Disc brake and drum brake

All in all a very comprehensive summary of the benefits and disadvantages of disc brakes in comparison to drum brakes. One aspect that hasn't been discussed though is the cost of manufacture of each braking system. To be fair, the question posed seeks only the differences in engineering however, cost of manufacture is ALWAYS a major contributing factor in determining which systems should be employed. In addition to being inherently more efficient, disc brakes are considerably less expensive to produce than drum brakes. Also, and important in vehicle handling characteristics, disc brakes carry less unsprung mass and so afford more responsive suspension.
14. ## Creating an Engineering Model the Old Way

A really interesting video JAG and one I've not seen before. The methods by which cars were designed and produced then bear little resemblance to the systems employed in present day car manufacture and unfortunately it's only too evident that many manual skills have been lost due to the advent of the computer age. In England there is a company called Morgan who refuse to upgrade their production methods, preferring instead to utilise the same means as they used in the beginning. Their cars have been 'hand made' for many years. When I visited the factory I was surprised to find that the oak former used to produce wheel arches is the same one used several decades before and the alloy body panels are rolled by skilled craftsmen. Despite this, or possibly because if it, Morgan's order books are very full for the next several years. Is the glass-domed Futura car shown in the video the one used by Batman and Robin? I thought that was designed by George Barris!
15. ## Is Form Fit and Function Sufficient for Interchangeability?

A very pertinent example by JAG that highlights one of the results of process-change in engineering production when communication between engineers is absent. Surface finishes formed by different machine tools are quite apparent in cross- section when viewed through a microscope, but not necessarily to the naked eye. Components that are produced on different machines, such as the lathe or milling machine, whilst they may adhere strictly to manufacturing tolerances, can offer totally different characteristics in operation such as variations in the frictional resistance referred to by JAG. Production engineering sometimes makes advancement by the 'suck it and see' method, but hopefully engineers will take heed of this post and always consider the surface finish that different machine tools leave behind.
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