Bolts vs Screws
Bolts vs Screws
(OP)
ASME Y14.5 'tends' to differentiate between bolts and nuts in the Fixed and Floating fastener formula section.
Is there a consensus amongst engineers/designers/cad operators as to the technical correctness of the definition of bolts verses screws?
Is there a consensus amongst engineers/designers/cad operators as to the technical correctness of the definition of bolts verses screws?





RE: Bolts vs Screws
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Cory
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RE: Bolts vs Screws
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http://www.bicyclesports.us/id193.htm
RE: Bolts vs Screws
RE: Bolts vs Screws
RE: Bolts vs Screws
RE: Bolts vs Screws
RE: Bolts vs Screws
http://www.boltscience.com/pages/faq.htm#14
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
Thanks, that helps a lot. Mon I will research the B18 standard for screws.
RE: Bolts vs Screws
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
The problem as I see it with the answer from Corblimeylimey and ctopher is that if you use say a M6x20 countersunk screw/bolt to clamp a plate to two other plates one thick and one thin, in one instance you use a thread and in the other a nut and washer so the same fastener becomes both a M6 countersunk screw and a M6 countersunk bolt.
My personal preference is bolts have external drives on them, be that hexagonal or even square (like a coach bolt) whilst screws have internal drives on them, like Phillips or Allen, however I am sure there is a very good reason why that is wrong.
I am sure this thread will have a few more twists and turns in it.
RE: Bolts vs Screws
When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - Thomas Jefferson
RE: Bolts vs Screws
CBLs first link h
Plus based on several of the definitions, where do set screws fit in?
I long ago gave up trying to work out the difference and if I care for an application make sure the threaded fastener I call up has an adequate description, preferably a spec.
KENAT, probably the least qualified checker you'll ever meet...
RE: Bolts vs Screws
Most of the old-school heavy-metal places I worked at in WI use "screw" for anything w/ threads, including hex head.
RE: Bolts vs Screws
Try working out positional tolerances from first principles.
A bolt, a cotter pin or a non-countersunk rivet can be assumed to be located exactly at nominal position. Your clearance holes must clear an area at least the diameter of the fastener, located exactly at nominal position. As the hole gets larger, it can shift off nominal, hence the MMC specification.
A screw, a dowel pin or a fabricated feature is located by a positional tolerance. The clearance hole located excactly at nominal position, must clear an area equal to the diameter of the fastener plus the positional tolerance. Again, an increased diameter allows positional error.
JHG
RE: Bolts vs Screws
I believe you mean they differentiate between bolts and screws ?
I.e. between floating fasteners (threaded fasteners with nuts) vs. fixed fasteners (fasteners threaded into tapped holes on a single parent body). The tolerances required for position of the fasteners will change depending on those circumstances, as you know having read that section.
Or maybe I am misreading things...it is Monday after all.
RE: Bolts vs Screws
This was generally how the old MS specs seemed to categorize them.
RE: Bolts vs Screws
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
How about cap screws, as opposed to socket head cap screws? Cap screws have hexagonal heads.
There is a contect to this terminology that has nothing to do with how we turn the fastener.
JHG
RE: Bolts vs Screws
I thought about hex head cap screws, but was kind of ignoring them. I didn't say it was a hard rule, I said that's how I think of them.
It seems from the concensus of this post, that there is a context to the termminolgy, but no one is really sure what it is.
Again, ignoring the anomoly of the Hex Head Cap Screw, I like my Dad's definition best:
"Bolts are big and screws are little."
RE: Bolts vs Screws
I agree there are 'lag screws' and 'lag bolts', but if you order a 'lag bolt', most likely you will get a piece of hardware in a bag or box labeled 'lag screw'.
Yes, there are 'socket head cap screws', but not 'socket head cap bolts'.
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
RE: Bolts vs Screws
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: Bolts vs Screws
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: Bolts vs Screws
A bolt is 25 to 50 yards of fabric, as supplied to a wholesaler.
I challenge you all to solve a GD&T problem with this information. :)
JHG
RE: Bolts vs Screws
"Bolt out the door after being scr.."
never mind...
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
RE: Bolts vs Screws
I agree that having screws/bolts be able to "morph" depending on useage is unacceptable. I hate to disagree with what I have considered an infalliable resource (Mach. Handbook), but this is where I'm making my stand!
My definition is going to be: If it will not accept a nut or is installed with a screwdriver, it is a screw. Otherwise, it's a bolt. And before we get into another debate, screwdrivers are flathead or phillips. I don't want to hear about "screwdrivers" with sockets for hex heads. Those aren't screwdrivers in my book. I don't know what they are. I guess boltdrivers.
I'm also not sure where other configurations of internal driving mechanisms fall (i.e. square, star, etc). I suppose since I definately would say that socket heads are bolts, then those would be bolts (unless they will not accept a nut of course!).
-- MechEng2005
RE: Bolts vs Screws
Therefore, no matter what type of head it has on it, it's a screwdriver. There are also 'nut drivers', same family as the screwdriver, but with a permanent socket end.
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
A screwdriver is also a mixture of vodka and orange juice, ideal for removing the bolt of cloth your female companion has wrapp... oops!
The original post asked about how ASME Y14.5M-1994 differentiates between bolts and screws. The final question was "Is there consensus...". Evidently, the answer to that is "No!"
JHG
RE: Bolts vs Screws
I agree...no consensus. Which is OK, as long as we know how to pick the correct screw or bolt for our designs.
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
Marcelino Vigil
GDTP T-0377
CSWP
RE: Bolts vs Screws
A bolt is simply a rod whose function involves being placed into something else that is meant to receive it, such as the bolt of a lock, a door hinge bolt and the traditional definition for a bolt.
The confusion might come from the fact that screw drivers are called screw drivers, even they are also used for bolts, which would explain the non-functional distinction I've and others have learned (use a wrench on a bolt, and a driver on a screw)...and the rest is history.
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: Bolts vs Screws
Thanks!
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
Yup. Then some nut put a screw thread on one, and things got screwy. Like this thread <bolting for the door>
RE: Bolts vs Screws
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog
RE: Bolts vs Screws
My last employer was a pipe foundry. The smallest fastener we had was a 3/8 SHCS. Everything there was a bolt. If you asked for a screw you would get a wood screw.
Now I work at for a semiconductor company were a 3/8 fastener is considered very large. We go down to a '0' on some applications. Everything here is a screw.
I will add that personally I go with the Machinery Handbook definition based on what the hardware is going into.
RE: Bolts vs Screws
In CPI work, all is 3/4" bolts and studs. In optics, it's all small screws, down to #00, or 1 to 1.5 UNM.
So we really go by 1)our industry, and 2) whatever the screw/bolt standard calls the fastener.
RE: Bolts vs Screws
Maybe your screwdrivers can have something besides phillips and flathead, but mine don't! I'm putting my foot down on this. You can't change my tools!
RE: Bolts vs Screws
3.1.1 Bolts
3.1.1.1 bolt: an externally threaded product designed
for insertion through holes in assemblies to mate
with a nut and normally intended to be tightened or
released by turning that nut. The only bolt that has a
washer face is the heavy hex structural bolt.
3.1.2 Screws
3.1.2.1 screw: a headed and externally threaded
mechanical device having capabilities that permit it to
be inserted into holes in assembled parts, of mating
with a preformed internal thread or forming its own
thread and of being tightened or released by wrenching
its head. Refer to Table 2 for a listing of type designations
for tapping screws and metallic drive screws.
RE: Bolts vs Screws
What kind of an engineer are you?
KENAT, probably the least qualified checker you'll ever meet...
RE: Bolts vs Screws
I think that's probably the answer the OP wanted, is ASME B18.12 referenced (directly or indirectly) by 14.5?
KENAT, probably the least qualified checker you'll ever meet...
RE: Bolts vs Screws
When the people fear their government, there is tyranny; when the government fears the people, there is liberty. - Thomas Jefferson
RE: Bolts vs Screws
When installing the heads on my old flathead Ford V8, I never screwed "head screws" into the block. In fact I have never heard of "head screws" I have heard bikers threaten to do something similar to their enemies.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Bolts vs Screws
Jimmy Carter.
Then why have we gotten the worst from Jimmy Carter?
RE: Bolts vs Screws
-- MechEng2005
RE: Bolts vs Screws
Screwdrivers is the common term. I've never even seen bolt drivers as a term before. I hope you are being sarcastic. If so, sorry for not catching on. If not, do a search on McMaster-Carr for screwdriver to see. The do one for bolt driver.
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: Bolts vs Screws
Yes, I was being sarcastic. Just trying to have a little fun with the topic. The fact is that if you ask me for a screwdriver to put in a socket head, I'll hand you the right tool. If I asked you for a bolt driver for a socket head, I suspect I would get the proper tool. =)
It's just sometimes fun to "play" with a topic. Engineer's don't get enough "play" time (at least where I work). It's either right or wrong. Sometimes I think things should be "technically wrong, but fun/amusing."
-- MechEng2005
RE: Bolts vs Screws
RE: Bolts vs Screws
KENAT, probably the least qualified checker you'll ever meet...
RE: Bolts vs Screws
Joe
SW Office 2006 SP5.1
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ATI FireGL X1
RE: Bolts vs Screws
Matt Lorono
CAD Engineer/ECN Analyst
Silicon Valley, CA
Lorono's SolidWorks Resources
Co-moderator of Solidworks Yahoo! Group
and Mechnical.Engineering Yahoo! Group
RE: Bolts vs Screws
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 08
ctopher's home (updated Aug 5, 2008)
ctopher's blog
SolidWorks Legion
RE: Bolts vs Screws
In my opinion anyways
-- MechEng2005
RE: Bolts vs Screws
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 08
ctopher's home (updated Aug 5, 2008)
ctopher's blog
SolidWorks Legion
RE: Bolts vs Screws
It's the verb, not the direct object.
How do you torque a socket set screw?
(which our friend MechEng2005 might call a socket set bolt)
RE: Bolts vs Screws
As I recall "allen key" tried unsuccessfully to run for president, and to beat Barack out of the Illinois senate seat---or was that keyes?
RE: Bolts vs Screws
Thank you.
Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 08
ctopher's home (updated Aug 5, 2008)
ctopher's blog
SolidWorks Legion
RE: Bolts vs Screws
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com
RE: Bolts vs Screws
:)
RE: Bolts vs Screws
ht