Questions tagged [bolting]

Questions on the design and materials used to connect pieces together using bolts.

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1answer
69 views

Weird screw size?

Probably a real stupid question but googling is not shedding any light so maybe not? A cap head screw of size 40xM8x10. What is the diameter and length of the screw? Diameter is 8mm obviously, length ...
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0answers
43 views

Rule / equation for optimal screw diameter?

Is there a rule / equation for the optimal screw diameter per wood thickness? I have a 16mm baltic birch plywood, I have two pices 30mmX20mmX16mm I want to butt join them at their profile What will be ...
2
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1answer
77 views

What is the physical significance of bolt elongation length?

Eurocode: design of steel connections mentions something called "bolt elogation length", defined as the grip length of the bolt plus half of the sum of bolt head height and nut height. But ...
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2answers
120 views

How do you calculate the shear force on the screws that connect a door to a jamb via hinges

I'm trying to calculate the shear forces on hinge screws or bolts. Here is a schematic of the door with the relevant values: First, I took a free body diagram of the door and its hinges. The ...
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0answers
48 views

Thread adapters larger than 1/2"

I have a 1/2-20 stud that I need to step up to a 3/4-16 stud. I searched around for 1/2-20 female to 3/4-16 male thread adapters, but was only able to find such a product on McMaster for sizes 1/2 and ...
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1answer
71 views

What type of fastener / rivet is this please?

I think I may have worked this out but I would love it if a real engineer could confirm it please? Is the fixing shown in the photos a shoulder rivet? Semi tubular? For the record the pictures show ...
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1answer
71 views

Are M8 screws double the size of M4 screws?

Found some printable M8 screws on Thingiverse (https://www.thingiverse.com/thing:4805480), which made me wonder if I can get M4 screws, just by resizing them factor 0.5.
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56 views

Is there a mushroom head bolt standard for sizes smaller than M4?

Is there a standard similar to DIN 603 / ISO 8678 (metric mushroom head square neck bolts) for sizes smaller than M4. DIN 603 only goes down to M5 (please correct me if I'm wrong). I did see similar ...
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1answer
52 views

What is the best way to fasten securely a load onto a hollow brick?

Due to the ongoing COVID pandemic, I decided to put a basketball hoop on one of our outside walls, so that me and my son can stretch a bit. The problem is that the wall I plan to put the basketball is ...
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3answers
75 views

Bolt preload confusion

I'm trying to understand bolt preloading. I found this analogy on Wikipedia. I understand that as the spring is loaded to some pretension and the block is inserted, as we apply an external load to the ...
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1answer
197 views

Distribution of Forces into 3D Bolt Group

I'm trying to create an Excel spreadsheet that takes a 3D bolt group with x y and z coordinates, applied loading, and determines the distribution of forces into each bolt based on weighting by the ...
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2answers
57 views

Reduce stress on holes

I have an aluminium bearing holder attached to one end of an aluminium plate as follows: The bearing holder is attached to the plate by two bolts on the bottom. The intended setup is to attach a ...
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1answer
76 views

Strength of bolts

I was wondering if it'd be a good idea to attach a 10kg load to the end of a movable steel rod by fastening it with just one M5 bolt. Looking at Misumi's datasheet, M5 (Class 10.9) has an allowable ...
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0answers
264 views

Why is the minimal bolt edge distance not affected by plate thickness?

Eurocode specifies minimum distances from a bolt hole to the edge of the plate. But why is the bolt diameter the only relevant parameter? Why isn't the minimal distance also a function of the plate ...
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7answers
4k views

Fixing a blind bolt hole when the first 2-3 threads are ruined?

One of my suspension bolts came undone while I was mountain biking recently, sadly I didn't notice. I landed a big drop with only 2-3 threads left engaged, and unsurprisingly it's ruined them. The ...
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1answer
951 views

Proof load for screwing into aluminium plate

I have a required clamping force for fastening two pieces of metal together, and am trying to work out if an m4 bolt will be sufficient. The pieces will be fastened without a nut, just a hole through ...
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1answer
84 views

Is there a rule of thumb to construe a screw

When your first idea is drafted you calculate which forces/pressures and so on are working on your system. And then you break the forces down into the single screws which are built in your device. ...
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3answers
673 views

What causes a fastener to lock?

I am rebuilding a car engine. With some of the fasteners I am unscrewing, I notice that a lot of torque is required to undo the fastener. It feels like a snap when undoing a fastener, rather than a ...
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1answer
191 views

How to find the diameter of bolts in a flanged joint?

So I'm given this question with the following diagram: Two sections of a pipe are joined in a flanged joint as shown in the Figure below. The difference in pressure from interior to exterior is 2 MPa....
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1answer
68 views

What does P0.35 stand for in a Tech drawing for a Bolt

Got a Tech Drawing today with measurements and all that. I understand everything except for one part where they've specified a bolt with M4 P=0.35. The M part I get but what does the P specify?
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0answers
40 views

Decision criterion if bolted joints are loaded concentrically or eccentrically

When dimensioning bolts I have to decide if the applied load is concentrically or eccentrically to the bolt axis (according to VDI 2230 but I think in other approaches too). But how do I decide and ...
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0answers
94 views

Calculating the lifting force $F_{Kab}$ with SolidWorks – according to VDI 2230

I’m not sure if my procedure to simulate the lifting force $F_{Kab}$ is correct. So I illustrate my way how to get the lifting force $F_{Kab}$ using SolidWorks and the simulation tool. I hope you can ...
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0answers
117 views

Calculation of critical internal thread according to VDI 2230 Part 1

I’m doing a “Systematic calculation of highly stressed bolted joints – Joints with cylindrical bolt“ according to VDI 2230 Part 1. In step of calculation R11 “minimum length of engagement”, when my ...
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1answer
152 views

Help identifying a fastener/screw

I'm trying to identify the pictured fastener. It's a single piece around the arm of a gas spring, allowing it to pivot. I've had to replace the spring, but the screw is size M8 while the eyelet on the ...
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3answers
1k views

Can I use a wooden flat screw head with a washer to mimick a pan head screw?

For example - I am installing a fold up table from Ikea, it needs to hang from the wall, as shown below. It explicitly says to use pan head instead of flat screw heads like shown in the picture, I ...
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2answers
1k views

Determining when bolt will bend

I'm attaching a metal pipe to a metal tube as shown in the below diagram. The bolt is threaded through one wall of the pipe and does not pass through the opposite wall of the pipe, but is tightened to ...
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2answers
226 views

How the amount of bolt's preload in a single lap joint can change the natural frequencies?

Few days ago someone told me that the amount of bolt's preload in a single lap joint can influence the natural frequency of the beam. So to test that out I modeled a 3D single lap joint in ABAQUS and ...
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2answers
277 views

Correct term for non-countersunk flat hex screw/ bolt?

There is a type of screw/ bolt that is flat on top so that it's almost flush when fully seated, but it is not counter-sunk, and it usually takes a hex driver (allen key). I see it used on Ikea ...
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2answers
2k views

Determine force distribution from a bolt pattern

Need some help designing a bolt pattern for a pressure tight enclosure. How do i determine the force applied at a distance from a bolt location so that I meet the minimum force to compress the ...
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1answer
34 views

What is the hardware called that can step a lever N degrees upon manual force?

I'm trying to build a step stool that has a rotating chair back that will rotate from top position (e.g. chair) into bottom position (e.g. step stool). I do not want a free rotation of the chair back ...
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1answer
121 views

Derivation on torque required to raise load, isn't there a force disapearing?

I drew a little picture: Try to use you imagination to view these pictures as profile of bolt threads. In derivation on torque required to raise load, the angle of friction (ro) is calculated like in ...
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1answer
120 views

Instrumented Bolt - Conversion of measure strain/stress to clamping force

As part of some experimentation on a bolted joint, I have used an instrumented bolt with a number of strain gauges. The testing has produced results of strain with respect to time. By using the ...
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2answers
19k views

Maximum shear force of metric steel bolt

I'm struggling to calculate with any confidence the allowable shear force for a metric bolt holding two aluminium pieces together. I only need an approximate figure, since I will allow a very large ...
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4answers
1k views

How to make screws stay tight under high vibration?

I made an electric skateboard (it works great, goes about 25mph) and the motor takes 4 screws to mount it. Motor is mounted to a 1/4 piece of aluminum. The screws go right into the motor and don't ...
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3answers
183 views

How to determine materials and torque for a flat setscrew that won't loosen, slip, or mar

I'm a non-engineer doing a little design project. I'm going to be running some M5-ish (have some flexibility) setscrews into a shaft of about 6mm. There's no reason why the shaft can't be flatted off ...
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1answer
1k views

Flanged connection studbolt length calculation

I am struggling with the ASME B16.5 code and the specified stud-bolt length that is taken into account in the tables (7, 10, 13, 15, 17, 19 and 21). If you calculate the stud-bolt length according ...
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1answer
425 views

How to build a pivot linkage for a robot.

I have asked this question in 3DPrinting.stackexchange forum but got no answer answer. Please take a minute to see if you can help. I am building a simple RWD vehicle using 3d printer parts. See the ...
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1answer
802 views

What is the name for a bolt hole with a slot that allows the bolt to be inserted or removed when the nut is loose?

I can't find the name for this kind of hole. It allows the release of the plate by just loosening the bolt a bit, without having to remove it completely. Searches using "teardrop" or "hole with ...
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1answer
4k views

Convert translational stiffness to rotational stiffness of a screw

I have the formula for the translational stiffness which is : However, what I would like to find is the rotational stiffness. Is there any formulas to convert from one to an other knowing the pitch ...
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0answers
1k views

Stiffness of members in a bolted joint

I'm trying to calculate the safety factor against separation of members in a design that looks like this: I know how to find the bolt and cylinder stiffness, but I don't know how to find the ...
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1answer
455 views

Do bolts become tighter or looser at cryogenic temperature?

In general, will screws tightened at room temperature become tighter or looser at very low temperature (5 K)? On the one hand, the screw should loosen because it will contract radially, while the ...
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2answers
983 views

Effect of varying diameter bolts on shear stress under eccentric loading

In my mechanics of materials class we are required to be able to solve problems with bolts in shear. Unfortunately our textbook doesn't cover this subject we only had a little bit of information given ...
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4answers
666 views

How would you refer to a bolt mounting slide as opposed to a simple hole?

I'm writing a patent application and my device incorporates a similar design as what I've seen used on Dovetale plates. However, instead of a preset hole for positioning a bolt to mount to, a grooved ...
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2answers
176 views

Rotating a bolt around the centre

I have a setup in which a bolt threaded on two ends with an unthreaded shank in the middle will be rotated by the unthreaded shank area. That is, the bolt's axis of rotation is roughly the red cross: ...
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2answers
119 views

What could be the downsides of leaving twist-off bolt splines in the interior of exterior columns?

I have a project where the contractor is using ASTM F1852 Tension Control (twist-off) bolts. The project is outdoors and uses weathering steel and weathering fasteners. The main members are hollow ...
3
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1answer
98 views

How often do you need to check torques on bolted flanges?

Due to the fact that pipe flanges rely on bolts, and bolts rely on friction, it seems obvious to me, as a manufacturer of piping, to recommend that bolt torques need to be checked every so often, to ...
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3answers
619 views

Measuring pipe bolt torque without a torque wrench

I've had trouble with leaky pipe flanges, since my flanges are made of plastic. The problem comes down to the fact that sealing a flange is based on torque. Torque relies on bolt friction, which can ...
3
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1answer
397 views

What boundary condition should I use for the edge of a blind flange?

When testing a pressurized pipe with off-standard flanges, often times the materials available to fabricate a blind flange of the correct size are limited to what is around. I've made it a habit of ...
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4answers
6k views

Many small bolts, or few large bolts?

I am affixing a servo motor with a machined enclosure to a base plate with drilled holes. The current design uses eight M-2.5 bolts in a figure U pattern (3-2-3) around the enclosure. Tightening that ...
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2answers
568 views

How is a self-locking hex nut (ISO 7040) used?

I'm interested in the usage of a self-Locking hex nut with a nylon insert (ISO 7040 or DIN 985). How is it used correctly? Is there a prescribed usage, or a norm that describes how it should be used?