Questions tagged [mechanical]

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120 views

Why does this thing that is not a screw have a screwdriver slot?

I am (partially) disassembling an old sewing machine to clean it up. While removing the bobbin winder, I found this thing that has a screwdriver slot, but it isn't a screw. This is the part: It came ...
2
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3answers
69 views

Inverting motor polarities automatically to close and open a door

Hi, I need to build a device that opens a chicken coop door. The idea is quite simple, a motor connected to an axle that pulls a string up just like a wench. It would be activated by a relay timer ...
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1answer
62 views

How can I measure gear efficiency?

I am doing a experiment on various gear combinations and am wondering How I can measure the efficiency (Torque loss) of each gear pair), I have a input shaft connected to the first gear and is also ...
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1answer
45 views

Why is the torque of an ICE low at low rpms?

Let us consider a basic 4-stroke single cylinder, direct port fuel injected naturally aspirated engine which is given a constant throttle. Now, why does it produce very low torque at low rpms, meaning ...
2
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2answers
58 views

Parallel beam load cells, force transfer and maximum load

I'm going to experiment with a parallel beam load cell like this one: https://cdn.sparkfun.com/datasheets/Sensors/ForceFlex/TAL220M4M5Update.pdf. I've read somewhere that for a setup shown on this ...
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0answers
23 views

Cargo box opening system below

I am currently trying to make a delivery drone similar to ones Amazon did. Basically the cargo box which carry the package must open to below in order to drop the package. What I want to do is exactly ...
2
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2answers
32 views

HPU minimum oil temperature

Two different HPU systems in different locations with slightly different oils Chevron Ranco HD 68 and HDZ 68 have the same minimum oil temperature 55. Their flash points are are 455 and 414 F ...
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1answer
68 views

Why would anyone “pull the stem out and stop the wristwatch at night or when not wearing it” in the context of mechanical watches?

I read this the other day while discussing mechanical pocket and wrist watches: Plus it is common practice to pull the stem out and stop the wristwatch at night or when not wearing it. You then have ...
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1answer
68 views

How can (many) mechanical watches keep track of the current day of the month when these vary so much over months and years?

Having dealt with dates and time in programming context for many years, I have realized what a nightmare our common calendars are, and how much they vary by the year/month/etc. Yet there are fully ...
1
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1answer
53 views

Dynamic model of a two-mass electric drive taking into account the Gear Ratio

Two-mass rotational system has the following form and is represented in following structural diagram. where $\tau_e$, $\omega_1$ and $J_m$ - motor torque, angular velocity and moment of inertia $\...
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2answers
89 views

Torsion of continuous vs simply supported beam [closed]

Say that I have a 2 span of continuous beam subjected to torsion, is the torsion value smaller than those 2 single span beam subjected to torsion of same value ?? I think the torsion of continuous ...
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2answers
80 views

Effect of multiple shear pins used in combination in a coupling

Does using multiple shear pins under a limiting torque case reduce the minimum required shear pin diameter for the coupling or is the complete load distributed over the shear pins regardless of the ...
1
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1answer
58 views

Do really “all mechanical watches need to be maintained properly”?

Somebody answered this on a different question: All mechanical watches need to be maintained properly. Every year or two they should be taken to a watchmaker for a service. This will include ...
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3answers
69 views

Are mechanical pocket watches inherently water-proof and last “forever”?

Recently, I bought a cheap (~$53) but elegant mechanical "retro pocket watch", newly made. That is, not an antique made in the 18th century or anything. So far, it's worked flawlessly and ...
1
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2answers
60 views

Looking for locking “lanyard” reel mechanism

I'm working on a system that requires a small cord (~3ft long) to retract up into a reel and lock in place so it cannot be pulled away from the reel. Sort of like a seatbelt mechanism after it's been ...
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0answers
36 views

Number of Kinematic Pairs

Kinematic pairs are the connection between 2 links that can have relative motion between them. But In six bar chain as shown below: There are five pairs for them to be a kinematic chain. But if I ...
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2answers
99 views

How can a mechanical pocket watch wind itself from movement, and does it really get damaged if wound “too much”?

Today I received the mechanical pocket watch that I had recently ordered. It was this one: https://www.trendhim.se/guldfargat-mekaniskt-retro-fickur-p.html#full-gallery I find it extremely fascinating ...
2
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3answers
79 views

What is this mechanical pump called?

I am unable to find it again but I once heard of a type of air pump that involved a pair of offset archimedes screws inside a cylinder. The point of the device was that as the screws would turn ...
0
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1answer
42 views

Peltier Module Set up isn't cooling

I have set up a peltier module with an aluminium heat sink, cooling fan, 12v, 7ah battery supply and thermal paste for the purpose of cooling water. At first, it performed well. It dropped down to 3.5°...
1
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2answers
66 views

Professional threaded insert in plastic?

I'm getting some plastic parts (made with HDPE) CNC machined. A few of these parts require the addition of threaded inserts. I've printed the parts myself using a 3d printer and when I add the ...
0
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1answer
30 views

Shape of the shaft of knurling device

I'm trying to design and simulate a simple knurling device. The shaft ( blue part ) has a flat surface at the other end, where the small grey pin connect the green body to the shaft. I guess you can ...
1
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0answers
48 views

Design a Jig and Fixture for 3-axis CNC Milling Machine

Newbie Here!!! This is my assignment task. I am required to design a Jig and Fixture for 3-axis CNC Milling Machine. The workpiece will be a simple aluminium block and it will be cut and shaped into a ...
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2answers
67 views

how many power stroke in 3 cylinders, 4 stroke at 3000 rpm?

According to some answers, in 3 cylinder , 4 stroke we have power stroke each 240°, as we have 1500 rev. Of 720° in this rpm, so we will have this: 1500 x 1.5 = 2250 power stroke at 3000 rpm, is it ...
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1answer
42 views

What is this object?

In framing the question, I can't be more specific as I have no idea (though a suspicion) about what this came from. I have a number of them that are several different diameters from 125mm to about ...
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0answers
24 views

Way to keep object on linear rail in the position you leave it in despite smaller external forces?

Problem: I have a rod on a linear rail system. This rod can be pushed forward or backwards. There is air blowing out of the front of the rod (~2 lbf) causing it to move to the back position by default....
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1answer
35 views

Identify bearing dimensions from its bearing number

In motors/pumps generally following bearings are used (ref: https://www.nke.at/en/bearings-applications/applications/electrical-motors): Deep groove ball bearings Cylindrical roller bearings Angular ...
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0answers
10 views

Reloading Press Powder Dispenser Pressure

Yesterday my Lee powder dispenser to my reloading press popped off gunpowder everywhere I had removed the top part of the container off and placed it back on, there is a "on" / "off&...
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1answer
55 views

Motor sizing for modelling

Im working on a headrest for a car that will electrically adjust up and down and have drawn up my plans. it now comes to the important questions, such as what motor to use. Ive been looking at motor ...
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2answers
303 views

Heat transfer Calculation, for Cooling for an aluminium box

To go into more detail, I basically have a controller and its housing is basically an aluminium box that I need to add heat sinks to. But first I need to calculate how much heat is being dissipated by ...
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0answers
26 views

Tiny sliding mechanism

I have been trying to build a sliding keyboard phone attachment for a while now, but can't seem to get anywhere. Basically, I want to combine my Moto Z Play with this cheap, generic bluetooth keyboard....
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2answers
50 views

Do you know any mechanism that can pass a thread through several holes?

Well i am stuck trying to figure out this problem, actulally i see a machine that can make it with a torus, a torus coilling machine. But that not work with a multi turus shape. I want to automate ...
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0answers
50 views

ABAQUS: How to connect a shell edge with a shell face?

I'm performing a buckling analysis of a stiffened aluminium panel. The panel and flatbar stiffener(2) is created as one 3D shell extrusion. The T-stiffener (1) is another 3D shell extrusion. How do I ...
1
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1answer
49 views

Specifications of Tensile Test Specimen?

I am Currently Working on Measuring Various Mechanical Properties of Metalic Materials using Universal Testing Machine (UTM) at Various Temperatures. I know that for Testing at Ambient Conditions, ...
2
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0answers
26 views

High articulation joints

Looking for advice or suggestions for high articulation joints (>57°) for an automotive halfshaft. Peak operating conditions are in the ballpark of ~1000RPM, ~300ft-lb torque. I've considered u-...
1
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0answers
40 views

Latch design for home exercise equipment [closed]

I have a latch design problem and need your help - many years in software engineering aren't helping me much here! Two pieces of 60x30mm RHS become parallel/adjacent (on the 60mm face), with a 5mm gap,...
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0answers
39 views

How can you convert 180 rotation into two separate motions?

I have a small servo that can rotate 180 degrees. I would like to get two different connected parts to move at different times, one part moving while the servo is between 0-90 degrees, the other part ...
1
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1answer
67 views

Bending moment when there are no constraints

I faced this problem in an old book (Hall Allen S., Theory and Problems of Machine Design; 1961) The answer according to the book is 592 [in.lb], but I think the bending moment should be 0 because ...
2
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2answers
61 views

Most efficient orientation of exhaust vents on top plate of chassis for air flow with regard to heatsink fins?

I'm looking for some advice from an ME or anyone who understands heat transfer,convection, etc. I'm currently laying out in Inkscape a top panel for an audio amplifier I'm building. Now, my question ...
1
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1answer
31 views

Arrow on Activity (AOA) Network Diagram

I have question-related to industrial management, actually, it is a problem on arrow on activity network diagram. I tried to solve the question my self, below are the images. If I did any mistake ...
2
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0answers
79 views

How is motor torque related to capstan equation?

I know that capstan equation relates $T_{in}$ and $T_{out}$ as $T_{out} = T_{in}e^{u \cdot F_c}$, where $u$ is friction coefficient and $F_c$ is wrap (slip) angle. In my situation, the capstan is ...
2
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1answer
55 views

Is there a way to convert a short throw in one direction into a long throw in two directions

I have a motor that I have created a simple adapter for; this lets us attach any parts we might design to solve the final problem: I would like to convert the motors motion to oscillating motion in ...
-1
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1answer
30 views

Can we coat brass with nickel by peen (mechanical) plating?

Is it possible to plate brass conductor with aluminum by peen plating?
2
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0answers
15 views

Is inverse hall-petch relation valid crystals larger than nanocrystalline?

The image shown here is of ceramics, where they varied the grain size and measured the strength. For example, let's take Al2O3. There we observed that strength first increased from 3 μm to 95 μm. But ...
2
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1answer
131 views

Calculate Torque Required

I am working on a school project that requires me to build a machine. I have designed the machine but I am stuck at torque calculation. The problem goes like this, the machine supposes to rotate a ...
0
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2answers
74 views

Regarding design of a compressed air delivery system based on a screw air compressor

I want to select a screw compressor for my application wherein I need a pressure of about 18 psig, and 300 cfm at the aforementioned pressure. The compressors I'm finding suitable for the system have ...
2
votes
1answer
28 views

What are the characteristics of a motor that will generate current and is powered by a 30 cc, 2-stroke small engine?

Problem: I am trying to hobby-build a generator using a (old, working, throw-away gas, yard blower) 30 cc, 2-stroke engine. The 2-stroke engine will spin a motor and I want the motor to generate DC ...
0
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1answer
75 views

Airsoft BB Funnel Design - Electric funnel jam solution?

I'm working on a design to feed Airsoft BB's through a funnel. A simple gravity fed system (ie. I don't want to force them out at speed) but every now and again the BB's get jammed at the end of the ...
-1
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1answer
321 views

Eulerian and Lagrangian --configuration— (continuum mechanics)

This is in continuation/related to the following question asked in the below link Eulerian and Lagrangian descriptions of velocity According to my understanding Lagrangian approach is an approach ...
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5answers
308 views

What is a purpose of learning G-code?

I might be wrong here. The solid modeling done in CAD like Catia, NX, Solidworks,etc can be taken as input in CNC and the desired shape and size of piece can be obtained.The CAD itself convert the ...
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0answers
44 views

RSS Tolerance calculation and usage

From my experience, I've been calculating RSS tolerances by squaring all relevant tolerances, summing them up and then square rooting the sums... ie: RSS=[Σ(tol^2)]^0.5 I've also heard of other ...