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General term for a technique that ensures that two parts can be mated only if they are meant to be mated, and prevent any other part from mating

The general term for a technique that ensures that two parts can be mated only if they are meant to be mated and prevents any other parts from mating is called Key Interlocking or Keying.
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What would be an ideal material to use for O-rings on a canister in a lubricant-less, high-velocity pneumatic tube system?

A commonly used material for O-rings in high-pressure applications is Fluorocarbon (Viton) which has good resistance to chemicals, high temperatures, and good sealing properties. Other materials to ...
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How to find press fit/ slip fit for non standard size parts?

The calculations for slip fit and press fit can be done using the following formulas: Slip fit: Hole size = Dowel Pin diameter + clearance (C) Clearance (C) = (Upper tolerance of the dowel pin - Lower ...
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Input power unit for Heavy Duty spool hose

A hydraulic motor would be a suitable solution for your application, given its high torque capability and ability to operate in harsh environments. To find a hydraulic motor that would suit your ...
1 vote

2-speed 2-direction gearbox design

A simple solution for a gearbox with the desired properties is to use a planetary gearset. Planetary gearsets can provide different gear ratios based on the rotation direction of the input shaft. They ...
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How to design a gear decoupling system?

You can consider using a simple mechanical locking mechanism such as a deadbolt or latch bolt that can be unlocked using a key, as well as a motor or servo to actuate the mechanism. This allows you to ...
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On a Diesel/hydraulic DMU train what exactly does the “go faster” lever control?

When you move the "go faster" lever in a Diesel Multiple Unit with a mechanical or hydraulic transmission, you are commanding the transmission to shift to a higher gear ratio. This allows ...
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Forcing a part into "home position"

One approach could be to use a spring mechanism to keep the block in the home position. For example, a spring could be mounted on the inside of the ring near the bottom and connect to the bottom of ...
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Backward stabilization of a Z-axis

It's better to place the stabilizing pieces behind the rails, as this would provide more stability to the system and help to keep the plate and the rail level. The placement on the edge of the plate ...
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Stress and Displacement of Cantilever Plate with a Uniform Load

For bending of wide plates, we typically use the so-called plane-strain modulus $\frac{E}{1-\nu^2}$, where $E$ is Young's modulus and $\nu$ is Poisson's ratio. For $\nu=0.3$, for example—typical for ...
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Is this proposed addition possible for an evaporative cooler?

The diagram is the proper design diagram for a evaporative cooler, BUT you need to understand a few things: The 25 degree air will be close to 100% relative humidity. Most people will not find this ...
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Stress and Displacement of Cantilever Plate with a Uniform Load

If you are after the deflection of the beam at any point along the beam (but also for most intends and purposes - see below for exceptions) the problem you are after is equivalent to the following 2D ...
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Is this proposed addition possible for an evaporative cooler?

Not only is it possible, it is the fundamental invention of effective "air conditioning" Historically, an "air conditioner" was an invention that controlled the humidity of air. ...
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1 vote

What would be an ideal material to use for O-rings on a canister in a lubricant-less, high-velocity pneumatic tube system?

Precise machining of metals can result in a cylinder/piston fit so tight that it cannot be inserted if the exit hole is blocked. This would be impractical, in my opinion, in your application, as ...
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1 vote
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Are there compressors that can compress both water and water vapor?

Water at "normal" pressures is assumed to be incompressible. However, if you subject water to about 200 atmospheres of pressure then its volume will reduce by about 1%. So, water vapor will ...
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2 votes

How to stamp a thin copper pipe?

Metal can be very ductile but it is difficult for humans to imagine since we don't normally work with forces that large. Look at how an aluminum soda can is made. It's like forming putty. To me those ...
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1 vote

Centrifugal Pumps Self Priming

Because sometimes your pump is placed above and some distance from the waterline. but lets look at the startup sequence when the inlet is full drained and the housing is still full of water: When you ...
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Flopping toy mechanism design

Usually the motor will be heating up when it reaches a "hard limit". At that point it still tries to move (but it can't) and draws too much current while it tries to move. I would start by ...
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-2 votes

Steel selection for building a trailer

I’m not a structural engineer but I do understand materials and statics. My degree includes engineering, physics, other sciences and math. Long story short I worked as a civil engineer. The first ...
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1 vote

Origins of the "threaded fastener pullout formula"

You are right about the shear cylinder. With a SF of three, the thread's pitch or angle are irrelevant at the point of greatest strength. They assume that ultimately the threads will yield a stripped ...
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Origins of the "threaded fastener pullout formula"

(adding to DKNguyen answer, and giving a slightly different perspective --hopefully). general calculation The calculation is indeed based on a cylinder surface/plane that transfer the force from one ...
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Origins of the "threaded fastener pullout formula"

I think you're correct about the cylinder thing. It appears to be a crude equation though since it does not include thread percentage or thread pitch and does not even appear to be assuming a ...
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0 votes

How to theoretically determine the flow rate for a fan design?

Flow rate = V_induced * Area of the duct (at the rotor plane) V_induced can be calculated using Momentum (or combined Blade Element Momentum Theory, BEMT), for open rotors. (this reference uses V0 ...
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Passive gas mixing valve that takes fixed ratio of gas from two different inputs

Such a thing exists for hydraulic system. It is not simple or cheap, but passive. You need two positive displacement machines for the airflows, like sliding vane or rotary lobe pumps. At least the ...
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1 vote

Can air compressors be used to boil water?

what you propose is capturing the waste heat given off by the cooling fins on the outside of an air compressor's cylinders while the compressor is running. This is certainly feasible, but note the ...
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Can air compressors be used to boil water?

Yes, submerge the hot parts in water. If you can reach over 100 C, the water will eventually start to boil. You could keep the water at a constant level using a fill valve, such as the type you find ...
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Can air compressors be used to boil water?

This is probably technically feasible (albeit requires a high level of sophistication and there are a lot of asterisks attached to it) but as mentioned above not practical or economical. Air has a ...
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1 vote

Bending stress in gears

Because energy/power is the invariant which is transmitted through the gearbox (i.e. the power remains the same, while rpm , torque and forces change) , it might help if you think about it in terms ...
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1 vote

Where do I find mechanism for paper flipping and refeeding in printers?

You could visit a goodwill thrift store and look for a derelict printer with a duplexer, buy it for $20, and take it home for disassembly. The goodwill stores in my area are usually awash in 2nd- and ...
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Tips on searching for components?

Listings like McMaster, Thomas-Net, Grainger, etc. are helpful- IF you are employed by someone and have a budget that lets you pay full price plus shipping for the things you require. If not, read on.....
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Where do I find mechanism for paper flipping and refeeding in printers?

When you dont know how to do something and you know it being done by other companies, you take a look at the patents database. Finding the name is another thing though. There is no inherent systematic ...
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How to theoretically determine the flow rate for a fan design?

For unducted fans a relatively simple very fast program to estimate the performance of a fan or rotor is at https://au.mathworks.com/matlabcentral/fileexchange/21994-analysis-of-a-rotor-blade-system-...
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For an ICE, how can torque to the left of peak torque rpm be lower?

Start applying brake to increase load torque, the rpm slows down. If you keep doing this, shouldn't the torque continuously increase as rpm goes down because you need to press harder and harder on the ...
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Distorted threads and bolt preload

If the torque is being applied to overcome distorted threads and the torque value is constant ie to a set vlaue, then the clamping force will be reduced. If the threads are "normal" with ...
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Retracting a Shaft into a bushing

A solenoid is a steel (magnetic) shaft surrounded by a coil of wire. There is typically a spring placing tension in one direction on the shaft. When the coil is energized, the magnetic field will pull ...
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Given the compression ratio for a naturally aspirated engine, how do I calculate the expected compression pressure?

The initial pressure is lower than atmospheric due to the pressure drops caused by filters and pipework. The reason why volumetric efficiency is calculated. Also why older car had vacuum gauges fitted ...
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Vertical reaction on a shaft with 3 bearing supports

It is possible with some simplification, which is however generally the case when modelling a real situation. Provided that the supports are basically pinned (unrestrained rotations) and deformations ...
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How much force is acting on the screws I used?

I think you just need to do moment equilibrium. There will be a horizontal force couple acting on the vertical members, which can be quantified as a product of the unknown force acting on a screw, ...
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Why Do the Fingers in Mechanical Pencils Fly Out?

The plastic fingers are moulded in the open position. During assembly and operation they are compressed. I imagine that the fingers are moulded so that with the ring in the position shown they are in ...
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Vertical reaction on a shaft with 3 bearing supports

With the given information, no. The problem is statically indeterminate. You have three unknowns (A,C,D), but only two possible equations (sum vertical forces, sum moments). To solve it, you will ...
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Different measured strain in beam experiencing pure bending

If the beam had previously been overloaded to point of plastic deformation then the strain readings will be incorrect. There is also the issue of repeated experiments causing permanent strain ...
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How can a joint with ball and socket type of movement be locked in place by a load

So a socket that is sliced much like a collet used in drills etc so that with no load the ball can move. When loaded an external taper like a morse taper clamps the ball in the socket as the socket ...
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How can a joint with ball and socket type of movement be locked in place by a load

I am trying to understand your question. In order to rotate the ball joint, you must apply a force. The ball joint could not move if it were to lock under any load. However, a joint that automatically ...
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How should one wind the coils for a BLDC motor to maximize torque, if nothing else matters?

The motor torque equation can be written as: $$ \tau = \ell D B N i = K_t i$$ $N$: effective number of windings $\ell$: rotor longitudinal length $B$: magnetic flux density $D$: rotor diameter $i$: ...
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How to solder the stainless steel rods

solder generally will not work on stainless steel (it can't stick because of the oxide that forms on the surface of the steel). You can weld it instead, using welding wire or rod specifically ...
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How would I find the minimum speed for a conveyor transfer to avoid collision?

I'm going to estimate some numbers here that you haven't provided, but you should be able to adjust the math as needed. Right off the bat we can forget about conveyor 3, since the rate at which staves ...
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Where will the load be applied on the beam

For a simple pendulum with a swing angle maximum of $\theta_m$, the tension in the string caused by the sphere is the sum of two forces, centripetal and the component of the weight of the sphere along ...
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Tension forces in a cable and reaction at the supports

Assuming that the posts are rigid (non deformable) and the rope is weightless, then pole L1 should experience only horizontal forces at the top (which will be converted to shear forces for the pole). ...
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1 vote
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What will the reaction forces of a support be in case of an angled cable

The reaction force is a vector in the direction (or opposite) of the cable. Note that the only way to have a horizontal cable is by having the other support higher. But if you do, a horizontal vector ...
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ball bearing on every gear?

You would typically need 2 ball bearings in that case. See the ball bearing has a point (ish) contact so to be able for you to design it carrying any possible axial loads youd need to have 2 ball ...
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