Identify the thread of this screw from my boat

[Scott Danforth]

Ha ha you saw that you tube vid too

No, read the book 50 years ago, also own the two bibles of bolted joints

 

[airshot]

The Phillips head was also designed for power tools as the slot head screw was difficult to use with power screw drivers. Phillips head kept the driver centered on the screw.

 

[Mc Tool]

No, read the book 50 years ago, also own the two bibles of bolted joints

Nope , Im not going to ask .
(but I could do you a great dissertation on rolled joints )

 

[Lpgc]

Thanks for the thread info.

I knew Sir Joseph Whitworth helped standardise imperial measurement threads in the UK in 1841, BSP pipe threads are still commonly used and based on the Whitworth standard.

I didn't know that in 1948 the UK, US and Canada agreed to use a common standard (the now very familiar UNC and UNF) that combined the US 60 degree flank (instead of Whitworth 55degree flank) and Whitworth rounded roots/crests, supposedly using the best aspects of both.

It must've been a pita before standardisation in 1841 with different companies all making different threads, which could even differ slightly batch to batch from the same company.

I remember being confused by Whitworth spanner sizes as a kid.

Originally thought it was a #10-24 but asking here seemed an easy way to confirm I wasn't confusing #numbered bolts / UNC / metric. At least I knew it wasn't going to be Whitworth hehe.

Why use a #10-24 when 3/16-24 UNC is so close?

 

[Scott Danforth]

because a 3/16" machine screw is a #10

 

[Scott Danforth]

Nope , Im not going to ask .
(but I could do you a great dissertation on rolled joints )

The Bibles of bolted joints

 

[Lpgc]

because a 3/16" machine screw is a #10

View attachment 414527

I know 3/16 is 0.1875 but thought #10 is 0.19", I think someone once told me there was a difference and a nut for one size might size might not work properly with a bolt from the other size (or vice/versa) even though there's only 0.0025" difference. I've also seen charts showing the #10 is 0.19" but I'm happy to trust your (and others above) judgement and have ordered a pack of stainless domed #10-24 x 3/4, thanks.

 

[Scott Danforth]

0.1875 is usually condensed down to 0.188 or 0.19.

 

[dingbat]

I know 3/16 is 0.1875 but thought #10 is 0.19", I think someone once told me there was a difference and a nut for one size might size might not work properly with a bolt from the other size (or vice/versa) even though there's only 0.0025" difference. I've also seen charts showing the #10 is 0.19" but I'm happy to trust your (and others above) judgement and have ordered a pack of stainless domed #10-24 x 3/4, thanks.

In machine world, a tolerance is assigned to the dimension based upon the presentation of the number. See below

In the case of a 10-24 UNC screw, the “basic” major diameter is 0.190” however, the actual diameter can vary from 0.1890” to 0.1818” diameter.

Had this been a 10-32 INF, the basic major diameter is the same 0.190” but the tolerances shifts to 0.1891” to 0.1831” diameter.

I lead the transfer of Technolgy when we bought and moved a British manufacturing company to the US in the late 80’s. Don’t get me started on whitworth and British standard hardware. I live that nightmare to this day…lol

 

[Mc Tool]

View attachment 414528

The Bibles of bolted joints

I do like to have a perusal of such books ,its surprising what handy bits of info one can find , even things you thought you would have learnt by now.
My biggest pile of books (not magazines ) would be reloading manuals followed by workshop manuals.