Questions tagged [fasteners]

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4
votes
0answers
75 views

Boeing 737NG pickle fork cracking. What determines the fastener layout?

Boeing 737NG aircraft are currently being checked for cracking in the "pickle fork" assembly that attaches the fuselage to the wings. The affected joint has 4 fasteners that attach the fork to the ...
0
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3answers
76 views

Fastening a Nut on threaded rod from the middle

Does there exist any type of Nut, that can be screwed on a threaded rod that can slipped in without having to go to the ends of the threaded rod? I can sort of imagine a Nut that was a ...
1
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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 ...
0
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1answer
84 views

What type of fastener is this?

Used to connect the chain for a window actuator to a U-shaped window bracket. The threaded end screws into a bolt hole (M5.5 female thread) on one side of the U-bracket. The tip of the fastener fits ...
0
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1answer
24 views

Correct sizing of fastener for console

Following situation: I need to mount a console holding a load to the edge of a 25cm concrete plate. I want you to check my reasoning. This is the situation: My thinking is: The load is 170kg, which ...
0
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2answers
51 views

Vibration table for tests (7-200Hz) from extruded aluminium profiles bolted together - good idea (?)

I need to design a vibration table (approx. 1000mx1000mm) to test products between 7-200Hz. I was wondering if it is recommended to make the table structure from standardised, extruded aluminum ...
1
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0answers
46 views

Recommended torque

I am working on an assembly where I have various screws, mainly metal on metal fastening. Where can I find a realiable source for recommended torque settings based on screw size, screw material and ...
1
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1answer
99 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 ...
2
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0answers
43 views

How to prevent movement in this 3 DOF setup?

I have a 3DOF platform that I'm trying to make more stable. It's difficult to explain in words what the issue is so I've added a GIF below. Any ideas of how I can get rid of this wobble? The DOF arm ...
1
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2answers
92 views

I have an unidentified press-fit nut that I need to reproduce, can anyone tell me how to find this?

I received these fittings as part of a package, but now we need more of them. Can anyone identify this assembly, or even better help me learn how to recreate it? My coworkers and I are stumped. ...
0
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2answers
1k views

Screwing into Rubber - Screw Selection

I am attempting to mount a device by screwing into ~2" of rubber (not sure what durometer or material, but it is decently firm, maybe 70 durometer). However, I am not sure what type of anchor to use (...
5
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2answers
703 views

Why are Whitworth threads angled at 55°?

You're probably thinking, "Well.. Why not? It's gotta be something.." Right? But 55° is kind of an odd angle if you think about it.. and it does seem like a pretty specific choice considering a ...
1
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1answer
93 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 ...
4
votes
2answers
333 views

When are Nyloc nuts indicated instead of cap nuts?

Are there any applications in which a Nyloc nut is preferred to a proper cap nut? As best I can tell: a Nyloc nut is just a specialized cap nut that will fail under lower torque and temperatures than ...
0
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3answers
82 views

Fat hexagonal M3 nuts, with outer diameter greater than 6 mm

This is a follow on from my previous question, Will standard M5 T-slot nuts fit these different 2020 aluminium extrusions? The extrusion has this profile: and here is a more in-focus photo, of four, ...
2
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1answer
1k views

Will standard M5 T-slot nuts fit these different 2020 aluminium extrusions?

I am trying to source the parts for a Wilson II 3D printer, and the recommended struts are made from 2020 aluminium extrusions, like so: However, in Bangkok, I can only find this type: Note that the ...
2
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1answer
1k views

Cleaning Shavings from Tapped Hole

I have a hole that contains metal shavings after I have tapped it. Is there a common method to clean out metal shavings from between the threads of the tapped hole?
2
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1answer
104 views

Hot Dip Galvanized Nuts

I’m in a position where I need to order high volumes of nuts and bolts for a project. I read through a South African National Standard, SANS 2001-CS1, in which it states that when I use hot dip ...
13
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2answers
2k views

What is this Y-shaped screwdriver bit, and what is its purpose?

I found this strange looking bit in a bit set of uncommon bits, including Security Torx, hexalobular, tri-wing, spanner head, 12-point flange, Torq-set and others. It's the only one that I could not ...
5
votes
1answer
580 views

How does Alloy 20 compare with Ti 6-4, C-276 and 316 stainless for corrosive service?

While I've designed tons of plastics for corrosive service, the fasteners to hold the plastics together are inevitably metallic. There have been a lot of ways to protect them from rusting (due to ...
3
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2answers
2k views

Rule for bolt thread engagement

When bolting something like a flange or a dead/blind end to a port on a pressure vessel (lets say rated to 2 ATM), is there a good rule of thumb on how much of the threading should be engaged into the ...
2
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0answers
147 views

Alternatives to stainless steel staples

I have to mount a glass fibre woven mat onto a stainless steel foil and using staples seems to be the only way to do it. The environment is one where a large variety of solvent vapors will be ...
1
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1answer
818 views

What screw for 2.0 mm plastic hole in housing

I'm thinking about using the Bopla UM 32009 housing for my product. It has little standoffs for attaching PCBs. These standoffs are made of plastic, and seem to be drilled (or molded?) to a diameter ...
1
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1answer
268 views

Flat Head Machine Screws with Undersized Threads

I am in search of a flat head machine screws with an 82 degree countersink that have 1/4-20 UNC thread, but have a countersunk head that is characteristic of a 5/16-18 standard screw. That is, I want ...
5
votes
4answers
720 views

Is there a standard name for a flanged threaded tube?

I have designed a custom part that I need, but it is so simple I'm sure there must be off-the-shelf versions available. However I don't know what it's called to search for it. The image on the left ...
2
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0answers
158 views

Thread-locking on AISC Clevises

I have a project that includes some standard AISC clevises on threaded rods in pure tension. I am trying to find guidance on how best to address the possibility that the rod could rotate with respect ...
9
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5answers
10k views

Why are most standard bolt threads single start?

When looking at thread descriptions, one of the basic properties is always the number of thread starts. As far as I could tell, all of the major standard bolt threads are single-start. This includes: ...
1
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1answer
2k views

Sizing plate washers for through-bolting to concrete

We are working on some equipment that is going to be attached to existing, 3,000 psi reinforced concrete floor slabs. In some locations, the best way to do this is to through-bolt and 'sandwich' the ...
1
vote
3answers
724 views

Tolerance Fit with Spring Dowels

I am designing a stainless metal base plate to mount an orientation critical sensor. The sensor has two 6H7 6mm deep holes to align it. One of the holes is a slot to allow for adjustment. The sensor ...