# Tag Info

7

The minimum clearance occurs when the largest possible shaft meets the smallest possible hole. That would be in this case a shaft of $50.02 mm$ in a hole of $50.00 mm$. The difference between the two is the $-0.02 mm$ from the solution you found.

6

There are two different aspects in your measurement. On the one hand, you are dealing with tolerances. On the other hand, you cover probabilities in measurement systems. Just for a rough calculation: The probability of the real length to be within 9.8mm and 10mm is 95%. The certainty of this measurement depends on the distribution of your probability. For ...

6

Answering the question: What are possible types of low cost sensors I can use? There are several types of sensors that can provide millimeter level accuracy. "Low cost" is a very relative term, so you'll need to do some shopping around based on your specific budget. Optical sensors- Included here are those of the type you listed, though it's a very ...

6

To get that sort of accuracy over that scale is not trivial and probably won't be cheap. For smaller size up to a few meters a portable CMM would be an option (here's an example). These have accuracy on the order of 10 $\mu$m and are used for things like high end/F1 car manufacture. However, CMM type instruments wouldn't be useful for anything larger than ...

5

Even the best metal tape measure is susceptible to significant thermal expansion over large distances. Try a laser measurement device ('electronic tape measure') instead: http://www.engineersupply.com/Laser-Measurers.aspx The laser distance measure, flat plates clamped to the object, and some shims of known thickness, should be all you need to precisely ...

4

For high accuracy over long distances it's typical to use general surveying techniques. You use a total station (like this) which will get you 1.5mm accuracy in a single shot. They're no laser tape measure. Repeated set ups /readings with some statistical corrections should get you easily below 1mm. Note too that these are immune to thermal expansion of ...

4

Measurement variations are very common and should be taken in to consideration when engineering systems. In most cases high precision equipment is available but might be cost prohibitive to justify purchasing for the project. Therefore, the goal of the engineer is to design the system to account for measurement variation. In this case the min and max limits ...

4

I think you need to understand what a "tolerance" means in an assembly items. My token view is, a tolerance is the permissible deviation of a part from its ideal design dimension. Additionally, under the non-ideal situation, the assembly will not lose its intended functionality, and desired level of performance. After that, you may start to tighten ...

3

It says the flats shall be within 0.100 units of radial dimension positioned with reference to 'A'. i.e. if you were to make the rim which is a perfect circle, then mill the flats at the three positions, what you should see is that the flats are exactly the same sectional shape and size if the machinist was perfectly precise. Some minor deviation from ...

3

I believe this is a related mating envelope related to datum A for the three plates, per ASME Y14.5-2009.

3

Your clearance range is the minimum hole diameter minus max shaft diameter to max hole diameter minus minimum shaft diameter. Answer: Yes. Your math seems correct. This is a useful tool: http://www.amesweb.info/FitTolerance/FitTolerance.aspx

3

If you live in a country that uses ACI standards, you might consider specifying flatness using an FL or FF number. ACI 117, Commentary Table R4.8.4 has this information, with flatness ranging from "Conventional" to "Super Flat." For the dimensions you have listed, specifying anything beyond "Flat" is probably overkill since your forceplate will likely ...

3

Standard threads are classified for accuracy by a tolerance class (You can see a bit about the metric thread fit classes at http://www.amesweb.info/Screws/IsoMetricScrewThread.aspx .) The screws you find at your local hardware store will probably be a relatively rough tolerance class, meaning that the threads are designed to have some gap between them, and ...

3

If it says +/- 1% then it means from -1% to +1%. in everyery standard i have ever seen. +/- is simply shorthand for writing a symmetric bound one can also make unsymmetric bounds like 0 to 1% or even positive positive bounds like +0.001 to + 0.025. Granted these are rare in electrical components but play a big role in mechanical engineering where its ...

3

There are general tolerances, often defined for different industries. You cannot expect that a surgical instrument is designed with the same general tolerances as a drilling rig. If you have found a norm for your industry, e.g. this ISO-standard, than there are still different classes of "tightness" you can choose from. Here should just check what ...

3

If the request is coming from whoever will be machining or inspecting the part, I would side with them. They know what they need to see to make sure the part ultimately meets the print. Also, since your first datum is on the opposing face this implies it is getting machined first, hence why it is a reference datum. The geometry of the face you're making the ...

2

The link provided by Ethan48 added a lot of informations. Tolerance classes: Note : * 6g is normally selected for commercial external (bolt) threads. Note : ** 6H is normally selected for commercial interrnal (nut) threads. The amount of movement allowed for external thread would be determined by axial counterpart to (radial) $T_{d2}/2 + es/2$. With thread ...

2

Understanding "without any special procedures" as meaning simply dropping the cement in a pile, it would probably end up with an inclination approximately equal to its angle of repose. Unfortunately, this value is highly variable, and a quick search has resulted in many different values: 15 or 20 degrees if fine or coarse (1) 40-44 degrees (1) 39 degrees (2)...

2

Was looking for other distance solutions, and came across this question. A sensor that I've found works well is the Sharp GP2Y0E02B (digital version) (newer version is the GP2Y0E03). Configuring it as an I2C sensor, using an Arduino, I've been able to get sub-millimeter resolution (0.156 mm - Range is ~630 mm, with 12 bit resolution). Almost didn't ...

2

The "incremental error" is the relative error in moving between two positions. (But only the USA would think of specifying a dimensionless quantity in "inches per foot" just to confuse people.) If the screw is commanded to move a distance $x$ (in any length unit!) the distance actually moved will be between 0.99995$x$ and 1.00005$x$ (because 0.0006/12 = 0....

2

Here is a link to a screw thread chart. http://www.engineersedge.com/screw_threads_chart.htm Note there are different tolerance classes, and also note the max is never over the nominal size. For the example 1/4-20 class 2: 0.2408 < d < 0.2489 class 3: 0.2419 < d < 0.25

2

As you have not placed constraints on the project implementation, consider that most welding requires a jig of some form to maintain alignment of parts. The use of the generality "most" also refers to simple clamping of two pieces prior to welding, which is common in non-critical alignment projects. Allowing for the specifications you've provided, consider ...

2

If you use ASME Y14.5, typical implied tolerances are +/-: 1/64 for fractional dimensions 0.01 for dimensions to 2 decimal places 0.005 for dimensions to 3 decimal places 0.0005 for dimensions to 4 decimal places You just list all these and whatever other common requirements you have in your drawing block for the part. This way every feature is inherently ...

2

Typically in my experience, your 3 orthogonal edges of the rectangular blank are your first 3 datums. Your dowel hole would be the first machined feature and since it locates the rest of the features, this would be your 4th datum. Your subsequent features would reference that 4th datum, as well as any of the original 3 to tolerance the features.

2

Assuming the limitation is power/heat buildup... The power dissipated in the motor winding is a square function... if you decrease the voltage by 50% (and therefore the current) you have decreased the power by a factor of 4... down to 25% of its original value. Any motor rated to run for 25min "ON" time, and at 80% duty cycle, will surely have no ...

2

This is a very difficult answer to answer within a single post but I'll give it a try. Tolerances, Cost and Machine capability The very first thing you need to remember is that tolerances are indirectly related to cost. More precisely, having tight tolerances means that two objects will be more closely matched compared to two others with looser tolerances. ...

1

Broadly speaking opening a valve further reduces flow resistance, at least up to point but more travel means greater acceleration and thus greater forces on parts, which is magnified as RPM increases. Indeed with mechanical valves you get to a point where the return springs can't act fast enough and you starts to get harmonic effects where the valves ...

1

There are a couple of issues. Firstly laser cutting may well not provide good enough tolerances or surface finish to reliably produce the fit you need and you woudl probably be better off drilling the holes, possibly using the laser to create a reference mark or pilot hole. Secondly poly-carbonate and acrylic don't really like this sort of interference fit ...

1

Presuming laser cutter and not laser printer, the project you suggest would be most effectively approached by creating test pieces. With 5 mm thick acrylic, there are enough variables to make it difficult to provide certain answers. Cast acrylic behaves differently from extruded acrylic. High power lasers are able to use higher travel speeds than lower ...

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