My general knowledge on those is that at longer lengths, the thread=20 won't go all the way to the end, but they are available fully threaded=20 and called "all-thread" bolts. Then there are also shoulder bolts, which are like partially-threaded=20 bolts, but the un-threaded portion will be a very close fit to the hole=20 size. On 3/7/2016 1:19 PM, David C Brown wrote: > Here in the UK I was taught that a machine screw is threaded all the way = to > the head whereas a bolt has an unthreaded portion so that there is no > threaded part wiithin the material been held together by the bolt. OTOH= I > have heard such bolts referred to as "Fitted bolts" > > On 7 March 2016 at 17:48, Neil wrote: > >> My general knowledge has been that once the diameter gets to 1/4", then >> they're called bolts, and then they're usually hex head. Yes there are >> exceptions. Taught to me by a machinist some years ago. However, I also >> call a 10-32 screw a screw, because the local hardware store (Home >> Depot) calls them that. >> >> For full context on this situation, the purchase list included "10-32 x >> 1" pan-head screws ". The teacher said that she had no idea what I >> wanted, so bought #10 screws (sheet metal), and 10-32 "bolts", and said >> that I was not specific. Saying no prob, that I just needed the 10-32 >> (screws) that she got, she argued that I should've said "bolts", and >> those are not screws. Even after showing her that the package actually >> said "machine screws", she demanded that they're bolts. I could not >> bother to get into it beyond that. >> >> I suspect we're no longer on PIC topic tag anymore though. >> >> >> >> On 3/7/2016 12:16 PM, Sean Breheny wrote: >> https://en.wikipedia.org/wiki/Screw#Differentiation_between_bolt_and_scr= ew >>> In the US anyway, the core distinction is traditionally whether the >>> fastener _needs_ a nut and is held still during tightening (bolt) or is >>> intended to screw into threads in the materials being joined (either wi= th >>> pre-cut threads or by thread-forming) (screw). Some things are clearly >>> bolts (carriage bolts since they cannot be screwed into a threaded hole >> due >>> to their lack of a driving feature and their square feature on the shaf= t >>> near the head). Some things are clearly screws (like wood screws or >>> self-tapping sheet metal screws). Other things are not so clear (like >>> typical pan-head machine screws which may also use nuts) >>> >>> >>> On Mon, Mar 7, 2016 at 10:56 AM, wrote: >>> >>>>> Maybe this is regional. I grew up in a junk yard. We had machine >> screws, >>>> not >>>>> to be confused with wood screws, and bolts. Bolts were big. Machine >>>> screws >>>>> were small. >>>> My understanding of the difference is that screws need a screwdriver, >> flat >>>> blade or cross blade (Pozi-drive etc.). >>>> >>>> Bolts require a spanner as they have a hex head, or require an Allen k= ey >>>> or similar tool, as they have a socket head, or don't have a means of >>>> driving, but require a nut on the other end, e.g. coach bolts. >>>> >>>> -- >>>> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >>>> View/change your membership options at >>>> http://mailman.mit.edu/mailman/listinfo/piclist >>>> >> -- >> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >> View/change your membership options at >> http://mailman.mit.edu/mailman/listinfo/piclist >> > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .