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Questions tagged [bolting]

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

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26 views

Horizontal flanged connection in an atmospheric container

I have a round container that is open to the atmosphere. Vertical flanges see the hoop stress from the content as main tension force. We typically have Dead Load, content, Wind and Seismic loads. ...
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6answers
2k 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
52 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
67 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. ...
5
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3answers
663 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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0answers
28 views

Jam nut holding torque

I've got a leadscrew that has an M5-threaded hole on the end. The original purpose of this hole is to accept a screw with a slightly-oversized washer, which prevents the "nut" (don't know the proper ...
1
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1answer
70 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....
1
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1answer
51 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
37 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
53 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 ...
2
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0answers
69 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
98 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 ...
4
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3answers
331 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 ...
1
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2answers
121 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 ...
2
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2answers
155 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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1answer
120 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 ...
3
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2answers
835 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
31 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 ...
1
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1answer
92 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
87 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
11k 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 ...
1
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2answers
713 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
92 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
763 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 ...
1
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1answer
317 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 ...
2
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1answer
518 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
3k 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 ...
2
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0answers
692 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 ...
5
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1answer
280 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 ...
4
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2answers
726 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 ...
2
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4answers
448 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
109 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: ...
5
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2answers
116 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
93 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 ...
3
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3answers
566 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
322 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 ...
9
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4answers
4k 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 ...
1
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2answers
542 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?
5
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1answer
645 views

Are stress concentrations a concern when replacing rivets with high strength bolts?

A common method of repairing old riveted structures is to replace any damaged rivets with new high strength bolts. When this is done, the new bolts are typically installed like they would be on a ...
8
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1answer
2k views

Can nuts safely be removed from bolts where the threads have been intentionally damaged?

On old bridge plans I have occasionally seen a note to "burr threads after installation". This was done to keep the nuts of bolted connection from loosening all the way and falling off of the bolt. ...
3
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1answer
215 views

How to determine the number of effective anchors in a base plate?

The situation is a steel baseplate that has to be anchored to concrete to resist lateral loads. The lateral load on the base plate is great enough that more than one or two anchor rods are required....
7
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1answer
1k views

Are standard structural bolts acceptable for all cold climates?

The specifications for standard (ASTM A 325) bolts do not list minimum service temperatures. I am thinking of outdoor applications like Alaska or Canada (lows of -60F) and wondering if the cold ...
7
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4answers
4k views

What bolts should I specify with Weathering Steel?

When using weathering steel (COR-TEN) on a project, what sort of bolts should I be using? I have yet to see fixings made of weather steel; presumably because the way it uses a sacrificial layer to ...
5
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2answers
6k views

What method can I use to make a pivot point in an aluminum linkage?

I recently had a project where I made an aluminum linkage (similar to a scissor lift) operated by linear actuators. Aluminum pieces were fabricated from 6061 "standard" aluminum stock, 6mm (0.25 inch) ...