# Questions tagged [tolerance]

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### What is the hole tolerance in hand tap guide?

What is the tolerance for through hole to match the UNC 1/4-20 tap ⌀ 6mm? (tap shaft diameter ⌀ = 6mm) I want to make the diameter of the hole such that the tap stands in the hole and doesn't fall ...
• 103
1 vote
188 views

### Distance sensors with accuracy of 0.1 mm?

I am looking for a sensor with 0.1 mm accuracy and a sensing distance of 1-10 cm for an industrial machine. The machine is used to ensure product quality following the assembly process. It will be ...
• 11
1 vote
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### how to interpret ISO2768-mK angular tolerance

How to apply tolerance for angle based on ISO-2768-mK? Cause I am confused about the statement "Permissible deviations in degrees and minutes for ranges in nominal lengths". Lets say I have ...
• 11
105 views

### Where can I find exact dimensions of a base of Eiffel Tower?

I am looking and looking and I can't find it: what are exact measurements of a base of Eiffel Tower in centimeters (or precision equivalent in imperial, not picky, can convert). All I can find ...
• 101
20 views

### How do I complete this tolerancing problem? Can someone walk me through Part 1?

I have been trying to solve this using rules of Basic hole and Basic shaft calculations but I keep getting it wrong
40 views

### How to prevent water droplets from staying on stainless steel / glass surfaces?

I'm designing a small tea strainer in the shape of a cylinder that goes into a glass bottle, which is also shaped like a cylinder. Currently, I'm still designing it in Fusion 360, but I'm facing one ...
14 views

### Recommended fit/tolreance for multipeice crankshaft sections

I am designing a machine that will feature a multi-piece crankshaft. The crankshaft sections will come apart in order to slide the crankshaft through some mounted ball bearings. The fit I am aiming ...
• 122
53 views

### Locating an angular surface using GD&T

I'm having doubts about how to dimension an angular surface using proper GD&T techniques. I want to achieve the 6 mm feature of size (FOS) at an angle of 89 deg. to Datum B to within an angularity ...
• 51
102 views

### Is a geometric straight tolerance allowed on threaded bolts?

A custom bolt-like part needs to be particularly straight. Can a geometric straightness tolerance be added on the threaded part of the bolt or can it only be added before threading? The example can be ...
168 views

### Tolerances for machining retaining rings on shaft

I am designing a section of shaft that will hold a 1.25" wide sprocket. I found The snap ring vendor states: Fits Groove Dia. 1.886 in Fits Groove Width 0.068 in The snap ring has slightly ...
• 122
1k views

### Reasonble position tolerance for 1.5mm dowel pins?

I am quite new to CNC machining and want to design two parts which should be accurately aligned with each other. I searched online and many people suggest the use of two dowel pins to align the parts, ...
• 101
499 views

### What does a divide symbol on a drawing mean?

What does this dimension (see image), and particularly the divide symbol in it, mean please? I'm not a mechanical engineer and couldn't find the answer by searching for terms with the word "...
• 63
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### What tolerance to use for fit by hand

I am desigining an aluminium part that takes in Wixroyd 32300.W0003 plunger with stainless steel body. The hole in question is 3mm and I want to be able to push-fit plunger with my hand (ie not by ...
1k views

### How to interpret general tolerances (e.g., ISO 2768)

I am quite new to mechanical engineering, but currently working on a project which I eventually want to sent to a CNC service for machining. Many services I found can manufacture to, e.g., ISO 2768-m ...
• 101
1 vote
207 views

### What should be the hole diameter (tolerance) at a given fixed diameter of the shaft?

What should be the hole diameter (tolerance) at a given (fixed) diameter of the shaft, to mate the head of the tripod and the guide shaft? For example, shaft diameter is 20mm. Material of head detail: ...
• 111
1 vote
522 views

### Design Factor and Design Uncertainty Calculation Question

I recently had a discussion about design factors and design uncertainty. Looking in Shigley's Mechanical Engineering Design, pg. 17, ed. 3, there is a detailed discussion of this topic. The authors ...
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### What are the Exact Rules for Significant Figures, Precision, and Uncertainty?

In the physical sciences (which are physics, chemistry, astronomy, materials science, etc.), we learned that the uncertainty is +/- the smallest unit (which is 1) of the last significant figure if the ...
46 views

### ISO 1101 & 14405: Required number of measurements for evaluation of dimensions and GTOLS

To my knowledge, standards ISO 1101 (for dimensions) and ISO 14405 (for GTOLs) make no statements whatsoever as to the required number of measurements for evaluation of quantities specified therein. ...
1 vote
40 views

### Bearing housing tolerances for mountain bike suspension pivot with through axle shaft

I have a Privateer 161 full suspension mountain bike. Ever since I bought it, most suspension pivot bearings run roughly when pressed into the frame. After the first 3 months I had the bike, I removed ...
• 11
293 views

### how do you define tolerances for moving parts so that they work properly?

I have a mechanism in CAD that I want to either 3D print or CNC mill. When I went to the school's shop the tech asked me what the tolerances of my parts where and I had no idea. How do I go about ...
1 vote
636 views

### What GD&T methodology should I use to specify alignment of two holes perpendicular to a shaft?

A round shaft 120mm long has two holes; one 10 mm from the end, the second 80 mm from the end. Each hole is perpendicular to the shaft's length. And here's the problem: the center line of both holes ...
• 11
111 views

### Tolerance value as part of formula

I work for a quartz resonator manufacturer, and we specify the parabolic temperature coefficient as Δf/f_o = -0.0340±0.006ppm/°C² The units on $\Delta f$ (the ...
1 vote
26 views

### Solidworks Z-axis Tolerances

I have a fresnel lens made by a company that has z-axis steps in it at the 10s of micron scale. That's fine except that it creates weird optical effects that I am having trouble simulating. I have a ...
3k views

### Why/when do we use a transition fit?

I'm self-learning a bit about preferred fits and tolerances and was wondering why transition fits were even a thing. Clearance fits I understand, applications where you don't want parts to touch and &...
693 views

### Conventions regarding sliding and press-fit tolerances for shafts and bearings

I often build things (3D printers, skateboard wheels, bicycle parts) that use off-the-shelf ball-bearings. These ball bearings are available in nominal mm sizes, and to the limit of my measuring tools,...
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1 vote
3k views

### Tolerances in a pin-hole assembly

Hi guys, can someone explain how to do this question? This question is under Geometric Dimensioning and Tolerances and I am clueless on how to tackle problem like this. EDIT This is the explanation ...
1 vote
126 views

### Applying ISO fits to radial bearings

Do you need to take the bearing size tolerance into account when creating the tolerances for the mating hole/shaft when using ISO 286 tolerances? For example, a 125 mm OD bearing with a desired H7 ...
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1 vote
2k views

### How to choose tolerance size?

I can not really understand how people decide what tolerances to set for a part or assembly. For example: When can I choose 0.2 mm and when 0.002 mm; and if I choose 0.002, why didn't I choose 0.001 ...
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56 views

### Specifying GD&T feature when not expecting the fabricator to measure it

For context: I work designing one-off science exhibits. Generally we design around pretty sloppy tolerances when we can, so things can be cheaper to make, with less precise tools, and at more ...
45 views

### Interference fit advice for permanent assembly

Many bicycle cranks have permanently assembled spindles on one side, as shown in the picture. This is a steel spindle inside an aluminum crank arm. I am not sure how these are manufactured. But I ...
• 181
707 views

### Coplanarity Profile Callout Confusion

From Krulikowski (1997), the callout for several coplanar surfaces using the Profile symbol is done by using two surfaces to establish datum plane A-B and then tolerancing the remaining coplanar ...
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689 views

### Do drawing dimensions have to start from datum?

When specifying the depth of a cut, should the dimension start from the datum surface or from the surface where the cut will be made? In the example below, a cut of 5mm is made from the surface ...
• 53
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### Runnung a motor continuously

I have a blower motor which runs on 12v with 25min running 5min rest rating. I want to run it at 5v-1amp (significantly lower speed) for at-least 14hour continuously. Will that hurt burn the motor? ...
1 vote
206 views

### Choice of Datum Features and Number of Datum Features

Consider a rectangular stock section with a dowel hole and other features of size (FOS) on it. The dowel hole serves to locate the entire part. Should my choice of datum features be what is most ...
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689 views

### What is an acceptable tolerance for a non-engineering dimension

I have part that I'm dimensioning and setting tolerances on. Some of the dimensions/features have engineering requirements (e.g. press fit) and I have the tolerances set correctly (e.g. H7). But I ...
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1 vote
143 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 ...
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1 vote
335 views

### Tolerance Analysis on clearance holes

I am designing an enclosure that holds a lens (clearance fit) and a photodiode on a PCB. The alignment of the photodiode to the lens must be pretty tight, thus I am using a boss on the enclosure (also ...
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1k views

### Difference between min/max clearance and min/max tolerance and relation between them

Recently I have seen a question as follows: Dimension of the hole is $50 +.02/-.00$ mm and shaft is $50 +.02/-.00$ mm.The minimum clearance is? My answer is .00 but the correct answer as per the ...
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### Is my tolerance stackup correct?

Major questions: Are 0.028 locating tolerances divided by two for left/right shift? Do overall drawing tolerances apply to a thru hole with a locating tolerance of 0.028 (max material condition)? If ...
70 views

### How to find a dimension that isn't explicit if there are tolerances

For a part like the one shown, let's say I wanted to find the dimension labeled 3", if it wasn't already labeled. Since there are tolerances already on the part, how would I determine the 3" value ...
• 31
1 vote
189 views

### Mechanical tolerances on a CNC machine

I have a project which involving several mating parts and also shaft guided through bearings, my issue here is that I don't have much experience with tolerances and manufacturing processes and I ...
• 135
1 vote
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### When tolerances are mentioned without +/-, should they be considered as a span?

In casual conversation, and often in bill of materials, tolerances are specified without the qualifier +/- xx%, often because the specific ± character is hard to obtain (especially in legacy UNIX EDA ...
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### Tolerancing considerations for temperature rated mechanical assemblies

I am currently designing a mechanical tensile testing setup to operate at different temperatures (-20 to 100 C) in a wet environment. I plan on machining two sets, one from stainless and one from PMMA....
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### What are functional and manufacturing datums

Can somebody please explain what is ment by functional datum and manufacturing datum, with respect to dimentioning and tolerancing.
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### Typical tolerances for valve lift using a camshaft?

I am working on a linear actuator for a valve. Wondering if anyone out there can point me towards the tolerances that are used for valve lift in a typical internal combustion engine using a camshaft?...
1 vote
301 views

### H6 tolerance shaft manufacturing

I’m a electrical engineer but an amateur in mechanics. I’ve been checking some tools and machines in the market for small works which would allow me to manufacture small but precise pieces, such as a ...
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### Interference fit in acrylic/plexiglass (PMMA)

I'm trying to fit a shaft into a hole in an acrylic piece that is 5mm thick to cause an interference fit. The shaft has a max. diameter of ⌀5mm and a min. diameter of ⌀4.988mm. I have access to a ...
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### How to provide concentricity tolerance in assembly?

I have a part(let's name it as supporting plate) which is gonna be welded on two parallel sides of a rectangular channel. The supporting plate has holes drilled at its end, the two supporting plates ...