# Questions tagged [bolting]

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

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272 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 ...
303 views

### What Tension Force will make the bolt to pull out of the nut?

I know how to calculate the bolt capacity for tension and shear, also how to check bolt bearing against different elelment such as steel or aluminum. There is a hanging bolt by which a bar is hanging ...
70 views

### T9 Torx Screw Thread diameter in Metric System

Helllo, I have to design a part that will have screws that can be taken apart with a T9 Torx Screwdriver. These are the screws that are taken apart first thing here. What is the thread diameter of ...
1 vote
2k 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 ...
48 views

I want to build the following swing for my grandkids: So I reckon that there will be a lateral loading on the countersunk bolt (shown in red), I would like to know what is the maximum load (in kg) ...
17 views

### Specification Tolerance Table vs Formula Discrepancy

BACKGROUND I was debating asking this in math exchange but opted for here since it is based on engineering specification. I was recently going through the specifications for Whitworth threads in BS 84:...
3k 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 ...
237 views

### Why is retorquing sometimes necessary and other times a mistake?

Bike mechanics will implore amateurs not to retorque a bolt. One must first undo the bolt and then retorque. Yet car wheels specifically require retorquing on a different day soon after installing the ...
11k 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) ...
78 views

### Bolt torque values according to thread size and alloy?

I am putting together a motorcycle from OEM and custom made parts. I have parts from 6061 and 7075 aluminium and TiAl6V4 titanium and I am putting bolts in sizes M6, M8 and M10 (some fine and some ...
37 views

### Shaft Nominal Diameter for M16 thread

I am looking to machine a M16 thread with a pitch of 2mm on a shaft, but I am unsure about what diameter should that shaft be in order to achieve the desired M16 thread. Does this change depending on ...
2k 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 ...
88 views

### Failing engine A-Mount (bad design by the automotive manufacturer?)

I currently own a Tata Nexon Petrol car (in India) where I have seen (on facebook, Telegram, WhatsApp owner groups and youtube) that the A-Mount on the engine has suffered multiple failures for some ...
46 views

### Bolt tensile load through an "intermediary"?

Following up on this question, does it change anything if the bolted arm is an intermediate arm (e.g. some sort of mating interface like below)? That is, the arm receiving the load is connected to the ...
16 views

### How is the taper of a bolt correctly notated? (Imperial)

I have a blueprint which states the following about two bolts which are used: Does that mean that the radius of the bolt decreases by 1/16" every foot, or the diameter?
125 views

### Why do some car's A-engine-mounts have bolts vs studs vs both?

I have come across engine mounts of various cars and am just curious primarily related to the "A" engine mounts where some manufacturers use only BOLTS, while some use only STUDS and some ...
22 views

Is it possible for straight threads to create a hydraulic/mechanical seal without the use of o-rings or sealants? From what I've read, in the oil industry buttress threads are used, in my application ...
175 views

### Different installation requirements for normal bolts vs torque-to-yield bolts

Why do stretch bolts need to be rotated 90 or 180 degrees after being torqued to a specified value? Why not just torque it to 120 nM instead of 100 nM + 90 degrees of rotation? Also would it be ...
131 views

### When should a bolt and hole be tapped at an angle, if ever, from a structural/strength standpoint?

Assuming the head of a bolt makes proper contact with its surface and clamps properly, and tapping an angled hole is not an issue, when would an angled bolt and hole (relative to the primary surface) ...
429 views

### Calculating how many bolts are needed to hold parts

Suppose we have a stack of thin metal sheets, layered on top of each other. Let's say 20 sheets, 0.2mm thick, and each sheet is 70mm by 70mm. Let's also say that the sheets are not totally flat, so ...
86 views

### Are bolt and nut dimensions standardized?

Given the nominal size of a bolt/nut, e.g M10, can one construct all other dimensions from it? Do these dimensions differ between manufacturers or are these standardized. If so, where can I find ...
23 views

### Securing Removable "Clocked" Handrail Knobs

I am in the process of machining and assembling a smokebox for a model train. The smokebox in question is approximately 35mmx35mmx22mm. There are a series of handrail knobs and rails that are to be ...
932 views

### Pull out force for a 5/8" tapped bolt

I am looking for the pull out force on a 5/8" bolt tapped into 1/4" thick tube steel. Does the thickness of the steel need to match or be greater then the bolt diameter?
54 views

### SOLIDWORKS-Bolting a COTS part from a STEP File onto an Assembly

Problem I have a STEP file with a few holes for bolts. I'm hoping to bolt this part into stock material in Solidworks. Example My first thought is to extend the holes into other connected components ...
106 views

### What is the purpose of drilled washers?

I was browsing this website and noticed that they have drilled washers. I could start to guess that the purpose of drilled washers may involve reducing weight by removing material (although this ...
1 vote
2k 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 ...
1 vote
143 views

### Tensile Force on Line of Bolts

I'm presented with a problem requiring some analysis to determine if an antenna bracket mounted to a concrete blockwork wall is sufficiently strong enough to endure a wind load given the known surface ...
67 views

### How to estimate effective area of contact between rough surfaces as function of surface roughness

The engineering problem that I am trying to solve is the following: I have two elements of a magnetic circuit that I must keep in contact through threaded fasteners. The primary objective is to ...
84 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 ...
49 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 ...
985 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 ...
3k 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 ...
55 views

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 ...
444 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 ...
1k 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.
161 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 ...
153 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 ...
1 vote
2k views

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 ...
8k 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 ...
1 vote
437 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 ...
128 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 ...
396 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 ...
1 vote
3k 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 ...
110 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. ...
695 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 ...
1 vote
719 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 vote
81 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?
50 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 ...
### 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 ...