Questions tagged [fasteners]
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59
questions
4
votes
4answers
1k views
Why can't screws be used for locating parts?
I remember hearing awhile back that it's not a good idea to use screws to locate/align parts. Why is that? Apparently dowel pins, or "locating pins" should be used instead. From my ...
2
votes
4answers
130 views
Are there any benefits to using a regular washer alongside a lock washer?
I am new to fasteners in general, and was wondering if anyone knew if it was acceptable to use a regular washer underneath a split lock washer. There are two applications, one is on top of a 3D ...
23
votes
5answers
5k views
Why exactly does a washer help distribute the stress around a bolt?
Usually the reason for having a washer under a bolt head is stated to be that it helps to evenly distribute the stress to the clamped material surface. But why is this?
I would understand if the ...
1
vote
3answers
117 views
Mechanical fasteners made of HDPE?
I need to fasten pieces of HDPE together but I’ve heard gluing HDPE is difficult (after all, glue comes in HDPE containers, and the glue doesn’t get stuck in the bottle).
Using mechanical fasteners ...
0
votes
0answers
49 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 ...
0
votes
0answers
42 views
Maximum strength size thread for aluminium sheet per thickness
Is there a rule of thumb, or a table which helps one determine what is the maximum strength thread size to use for aluminium sheet?
I am interested in threading 3mm, and 2mm thick sheet aluminium. I ...
0
votes
1answer
73 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 ...
0
votes
1answer
48 views
What type of fastener is this? How does it work?
I'm trying to find more information on this type of fastener. It looks like a variation on a bayonet mount but I'm not exactly sure how it is locking in place.
2
votes
1answer
89 views
Are concrete screws suitable for repeated removal and reinstallation?
Is a concrete screw like the HILTI HUS3 removable?
I.e. can it be repeatedly unscrewed and reinstalled as required? Will this damage the fixing or the hole in the concrete?
We're thinking about using ...
0
votes
2answers
45 views
Mounting a digital indicator on a plate
I have a flat aluminium plate and I need to mount a digital indicator[1] on it.
The digital indicator doesn't seem to have any mounting holes itself so I
think I need to use a clamp to hold it.
I don'...
0
votes
2answers
167 views
What is Proof Load of Bolts?
I seem to be getting conflicting information. Shigley's Mechanical Engineering Design textbook states that, "proof load is the maximum load (force) that a bolt can withstand without acquiring a ...
0
votes
0answers
26 views
Is there a term for this kind of eccentrically threaded fastener or washer that has wrench flats and curved faces
Is there a standard term for this fastener or for the kind of problem it is intended to address?
0
votes
1answer
66 views
Mounting methods for thin wall cast aluminum
Having a cast aluminium enclosure with the 3mm wall thickness. now I need to mount this to a mounting plate which fixed in vertical walls. can I have some idea on how should I choose the appropriate ...
0
votes
1answer
26 views
Fasten adjustable perpendicular cylinders rotating on axis
What part(s) make it simple to secure two perpendicular cylinders together when one of the cylinders is rotating on its axis? In the drawing below, C(3) rotates with a simple motor. C(1) and C(2) ...
0
votes
1answer
58 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 ...
0
votes
0answers
70 views
classes and grades of steel and stainless steel
I'm trying to learn the standard nomenclature for the steel and stainless steel mainly used in the bolts, screws, nuts, and other fasteners in general. So far I have created this table:
| Metric ...
0
votes
1answer
252 views
How to remove/replace a screw with a lock washer in a tight place
I'm trying to remove the screw in the images below from a metal cover.
The screw is locked in place by what I believe is called a locked washer. The screw can rotate, but I can't move it in and out. ...
1
vote
1answer
98 views
Detachable tubing connections (joints) for frame assembly
I am looking into fabricating a steel tubing frame that needs to be dis/assembled (applies to many larger furniture like bed, shelving unit, wardrobe, cupboard, cabinet, ...).
What are the variants of ...
3
votes
0answers
47 views
Aerospace bolts and washer combination
In my aerospace company we have repetitive discussions regarding the stacking of low tolerance fasteners with non-countersunk washers. For example a fastner NAS6703-X (size 10) has a max. base radius ...
1
vote
1answer
255 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 ...
0
votes
1answer
444 views
What's the best way to design a joint with two fasteners?
When you're trying to design a relatively long joint with only two fasteners, what's the best way to arrange them? Since fasteners effectively radiate a circle of clamping force around them, what's ...
-1
votes
1answer
40 views
Serrated locking part
I need to fixate something at adjustable approximate angles. It doesn't need to have a lot of holding power. So the idea is to have washers/nuts that are serrated, that when closed in together, locks ...
-1
votes
1answer
17 views
Looking for the name of this torque-arm post (to order one OTS)
It is a post that has an arm that can swing out so that you can torque on the post. I've seen it before but not sure where!
2
votes
2answers
1k views
M# Screw mm per turn?
So is there a standard rule of thumb, or equation about the distance the end of a screw will travel per rotation?
Conversely, how many turns it will take to travel a specific distance?
Say I have an ...
0
votes
0answers
22 views
"Barbed" fastener, ideally with a release
I'm trying to identify a fastener or type of fastener. I have a stud/post that comes up through a board and the fastener is something that would push on and hold in place. Ideally it would be ...
1
vote
1answer
953 views
What does "Lg" mean when defining form of screws
The context of this question is the Form, Fit and Function (FFF) rule defined in ASME. It states that form is used to define any product with reference to its size, mass, shape, dimensions, and other ...
1
vote
2answers
269 views
Can I use a NPT fastened device to vacuum or 10^-2 Torr?
I am designing a flange to be use to maintain a pressure of 10-2 Torr for at least 3 months. I am using an o-ring seal from my (device) to the product weldment. I am looking for feedback on using NPT ...
1
vote
0answers
30 views
Permanant extension for Fastener
I have a fastener with an accessibility problem. At the time of installation, the fastener is at the bottom of a crowded box with obstructions varying stiffness (Metal Plates and harnessing). It is ...
1
vote
2answers
44 views
Dimensioning of beam pressed by screw in assembly
I need help dimensioning a screw-beam system of a press. I built one prototype but the beam is bending too much.
Below is a sketch of my press. In the middle it has a fixing screw which presses ...
4
votes
0answers
134 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
votes
4answers
572 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
vote
1answer
89 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.
...
6
votes
3answers
675 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
votes
1answer
94 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
votes
1answer
38 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
votes
2answers
60 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
vote
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 ...
2
votes
2answers
182 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
votes
1answer
66 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
vote
2answers
124 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
votes
2answers
3k 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 (...
6
votes
2answers
2k 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
vote
1answer
122 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
739 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
votes
3answers
146 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
votes
1answer
2k 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 ...
3
votes
1answer
2k 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
votes
1answer
138 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
votes
3answers
4k 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
2k 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 ...
