Questions tagged [threads]
84 questions
12
votes
5 answers
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:
Unified Standard (UNC, etc.)
National Pipe…
hazzey
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10
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2 answers
Are threads machined from high tensile steel more susceptible to damage?
I have an ASTM A311-04 1.25" diameter round 1050 steel bar that exhibits a tensile strength reading of 155,227 PSI. Normally, we receive material in the 13-133,000 PSI range. The bar is machined to a 5/8-18 UNF thread.
We have experienced instances…
Kevin14009
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8
votes
1 answer
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.
An example of this practice can be seen in this…
hazzey
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6
votes
7 answers
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 rest of the threads (another 20 or so) are fine. …
Codemonkey
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6
votes
1 answer
How are non-continuous internal threads plastic injection molded?
I'm trying to figure out how the heck some of these plastic bottle caps are injection molded. By having the thread on the inside of a cap, this obviously creates an undercut.
Now I've watched some videos on Youtube on the process, and I can see…
Davbog
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6
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4 answers
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 perfect equilateral/equiangular triangle consists of…
voices
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6
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1 answer
Is the tolerance of pitch of a thread standarized?
As I was browsing ISO 965-1 it defines tolerances on a plenty of variables regarding metric threads, but it gives the pitch of the thread as a simple number from an allowed set ( 3 – 2 – 1,5 – 1– 0,75 – 0,5 – 0,35 – 0,25 – 0,2 ), and no tolerances…
SF.
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5
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2 answers
How to let a "screw" leave and reenter a thread
The setup
Consider a cylinder inside another cylinder (placed with their symmetry axis horizontal).
The inner cylinder is about Ø100 mm in diameter and a centimeter or two in lenght/thickness. On the perimeter there is a thread. This cylinder is…
Steeven
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5
votes
3 answers
What does "28" and "27" mean on my metric thread pitch gauge?
I have a metric thread pitch gauge that came in a tap and die set, it has pitches like $0.75$, $0.8$, $1.25$, etc. which is the distance between each thread. However there are two gauges that say $27$ and $28$ - I thought maybe it means $0.28\text{…
jhabbott
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5
votes
3 answers
Cutting flattened out "threads" to prevent small-scale slipping
I have a product where we transmit quite a lot of shear force through a small bolted join. On our current design the contact area is about 10mm², the bolt is M2, and the force is 45N, and it works quite well. But now we want more, the requirements…
Jack B
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4
votes
1 answer
British tapered pipe thread; Wall thickness? & Thread designation tpd?
I have to draw two custom pipes, 1 1/4" & 2", with on one end male tapered pipe thread and on the other end parallel pipe thread. The connections are Parallel female thread with a tapered male thread, with Teflon tape as sealant.
I'm familiar with…
SimpelenLeuk
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3
votes
3 answers
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 change even between different bolt diameters.…
Mark
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3
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Thread identification
I am having a very difficult time identifying this thread. This part is a plug that I am trying to replace because the threads were stripped.
The best fit for pitch is 11 threads per inch (imperial), but the major thread diameter is 32mm. It does…
user8908459
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3
votes
1 answer
What thread could this camera motor be?
Firstly, I am sorry that the title of this question isn't helpful. I have bought these motors for a project:
5V 7mm 2 Phase 4 Wire Stepper Motor
I assumed that the 1.7mm diameter threaded shaft would take an M1.7 nut, but it does not. Standard…
JB515
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3
votes
3 answers
Making precise, intricate measurements
What's the best way to precisely measure intricate mechanical parts?
For example, notice the tiny differences between the pitch in these two threads, and the tiny variations in external width of the cylinder:
I've been using a micrometer and a…
voices
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