Jdsk wrote: ↑14 Jan 2023, 3:54pm
For every attempted definition of the distinction between screws and bolts there's an exception in how the words are used for real objects in the real world.
That includes attempted definitions based on whether they end up inside a material or protrude and have a nut on the end, and on whether they're threaded all of the way or not. The former, as used above, is a much more useful engineering distinction than the latter, but there are still exceptions.
No, the application is straightforward and well understood. Bolting something together is a clamping force, screwing something together relies on the thread gripping. There really are no exceptions to that. The fixing used can often be interchangeable, if you wiki hard enough I'm sure you'll find fixings miss-named and mis-described, or where something other than a nut is used to bolt into, or bolts with full threads, but the two applications are distinct and easily definable.
Yes, it's a very useful distinction in applications. And, as I suggested above, much more useful than whether a fastener is fully threaded or not.
But the question was about objects not applications.
thirdcrank wrote: ↑14 Jan 2023, 12:59pm... although at my own - ham-fisted - level. I cannot now remember the difference between bolts and screws.
...
PH wrote: ↑14 Jan 2023, 4:20pmThe fixing used can often be interchangeable...
And that supports the conclusion that there isn't an absolute distinction between bolts and screws.
Carlton green wrote: ↑14 Jan 2023, 4:43pm
A bolt has a plain or unthreaded section next to the head, only part of the shaft is threaded. A machine screw is threaded along the whole length of its shaft.
A bolt doesn't have to have any thread at all: a rivet is a bolt.
Oxford English Dictionary:
Bolt:"A stout metal pin with a head, used for holding things fast together. It may be permanently fixed, secured by riveting or by a nut, as the bolts of a ship; or movable, passing through a hole, as the bolts of a shutter."
Screw:"A mechanical device or implement with a helical ridge or groove and which is operated by turning"
Rivet:"A short pin or bolt, the headless end of which is flattened or beaten out after insertion in order to fasten two or more things securely together."
So a bolt is either a rivet or a screw, but although the definition of a rivet doesn't preclude threads, it can't be both, because a thread on a rivet couldn't still be operated by turning.
Last edited by axel_knutt on 14 Jan 2023, 5:35pm, edited 2 times in total.
“I'm not upset that you lied to me, I'm upset that from now on I can't believe you.” ― Friedrich Nietzsche
PH wrote: ↑14 Jan 2023, 4:20pmBolting something together is a clamping force, screwing something together relies on the thread gripping. There really are no exceptions to that.
That's a circular argument, you presume a definition, then use it to define itself: "It's a bolt if it clamps...if it clamps it's a bolt".
“I'm not upset that you lied to me, I'm upset that from now on I can't believe you.” ― Friedrich Nietzsche
Carlton green wrote: ↑14 Jan 2023, 4:43pm
A bolt has a plain or unthreaded section next to the head, only part of the shaft is threaded. A machine screw is threaded along the whole length of its shaft.
A bolt doesn't have to have any thread at all: a rivet is a bolt.
Oxford English Dictionary:
Bolt:"A stout metal pin with a head, used for holding things fast together. It may be permanently fixed, secured by riveting or by a nut, as the bolts of a ship; or movable, passing through a hole, as the bolts of a shutter."
Screw:"A mechanical device or implement with a helical ridge or groove and which is operated by turning"
Rivet:"A short pin or bolt, the headless end of which is flattened or beaten out after insertion in order to fasten two or more things securely together."
So a bolt is either a rivet or a screw, but although the definition of a rivet doesn't preclude threads, it can't be both, because a thread on a rivet couldn't still be operated by turning.
OK then, I must be wrong. Perhaps someone will volunteer to tell these suppliers of their errors and the relevant standards organisations too .
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
What about ISO 888 and didn’t the sites that I referenced above have standards linked to them too? We are supplied with products that meet standards - well assuming that we buy from UK, European or North American manufacturers.
ISO 888:2012 specifies lengths and thread lengths for bolts, screws and studs for use in appropriate product standards and other relevant documents, e.g. for parts per drawing.
It applies to bolts, screws and studs with ISO metric screw thread according to ISO 68-1.
Don’t fret, it’s OK to: ride a simple old bike; ride slowly, walk, rest and admire the view; ride off-road; ride in your raincoat; ride by yourself; ride in the dark; and ride one hundred yards or one hundred miles. Your bike and your choices to suit you.
ISO 888:2012 specifies lengths and thread lengths for bolts, screws and studs for use in appropriate product standards and other relevant documents, e.g. for parts per drawing.
It applies to bolts, screws and studs with ISO metric screw thread according to ISO 68-1.
Unfortunately it's paywalled.
Does it attempt to define a difference between bolts and screws?
I think this thread might drift into lamp/bulb territory with those that know using the correct term and everyone else the popular albeit wrong term...
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