Difference Between Bolts And Machine Screws

Hi,

I was wondering if you could clear something up for me....as per the subject....what's the difference?

Is it to do with the thread length IE a machine screw is the whole length where as a bolt is only a fraction of the length?

Cheers,

Michael

Reply to
Michael
Loading thread data ...

"Michael" wrote in message news:bkxii.16982$ snipped-for-privacy@text.news.blueyonder.co.uk...

Chris

Reply to
rack2000

I've always called them set screws (fully threaded length) rather than machine screws. Conversely, I've always thought of machine screws as rather small diameter set screws with a c/sunk head.

Peter

Reply to
Peter Neill

They're only for *small* machines

Big machines need big machine screws. I don't think they need to be countersunk, they can have round, pan, whatever, heads.

Tim

Reply to
Tim Leech

Wikipedia told me that machine screws have thread on the whole length, but it didn't specify what is classed as a bolt - so I figured it may be something to do with the thread length.

Cheers,

Michael

Reply to
Michael

That's what I thought. I think we're basically right, but another common definition seems to be that a screw is intended to screw into a part, whereas a bolt is designed to be usee with a nut. Like most things, it can get much more complicated.

This page says that some very short bolts can have threads all the way to the head.

There's even a 21 page document to help US customs decide whether to use the duty rate for bolts or screws, which are apparently different!

Dave

(Yes, I was bored)

Reply to
Dave A

I suppose we should approve of customs officers and other subterranean life-forms being given pointless 21-page documents to try to understand.

From my earlier career, I must say I found customs duties even more stupid and pointlessly complex than VAT, and that's saying something.

David

Reply to
David Littlewood

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.