BikeAlmanac

In case you've ever wondered:

Inch-based sizing is controlled by the Society of Automotive Engineers, and sometimes inch-based sizing is referred to as "SAE." That organization sets the standards for machine parts, such as thread per inch on nuts and bolts, head sizes, and thread pitch angle (60 degrees).

You may hear a bolt referred to as 6x1 ("six by one"). That means it's outside diameter is six millimeters, and the threads are one millimeter apart.

Or, in an SAE bolt, you may come across 1/4x20 ("quarter twenty") which a quarter-inch in outside diameter, and has twenty threads per inch.

Metric nuts and bolts also use 60 degree angles, except for the Italian standard, which is 55 degrees.



55 degrees was also used in an old British standard called "Whitworth" or "British Standard Five," also known as "BSW" and "BS5." Most Whitworth wrench sizes are not interchangeable with SAE. In Whitworth, nuts and bolt heads are 5/3 of the major diameter of the bolt. You'll only find Whitworth nuts and bolts on old bicycles made in the United Kingdom.

cpach

Dude, stop spamming the forum with random unsolicited information. This is a discussion forum and your post is not formulated to create a conversation.

Kontact 

"Did you know the human head weighs eight pounds?"


- Jerry Maguire

02Giant 

Maybe I should stop calling people air-heads.

SquidPuppet

Yawn.........

jj1091

All of this sort of info you post can be found on Sheldon Brown's site, an already-existing sort of Bike Almanac. It's not helpful in the form you present, since you're providing info in want of an audience. It's like going into a park and doing handstands hoping people will be amazed. They won't, they'll just see you as annoying.

shelbyfv

+100

Bald Paul

You may find this useful as well.

MePoocho

Gotta put this on the wall next to my drill press for 'quick reference'. I've been dig'n everywhere for a guide like this. You are out of luck OP.

GrainBrain

"For holes countersunk wrong side"

Finally!

TimothyH

Prestripped for easy overtorquing LoL.

That graphic is pretty funny.

Dan Burkhart 

Thanks, you just salvaged this thread.

SquidPuppet

It's very funny, and very sad, that I am familiar with too many of those special requirements.

HillRider

As are most of us.

cny-bikeman

I guess I'm no longer looking like a troll by initially questioning the value of the OP's posts.

HillRider

1. You never did appear to be a troll.
2. Lots of us agree with your assessment.

bikingbrit

Balderdash! I think you are confused with "British Standard Fine" (BSF) which was a fine thread version of Whitworth.

wheelreason

Wait, SAE and metric are different? Maybe the Earth IS flat...

Dan Burkhart 

It occurs to me that the OP is getting beat up here because he tried to short cut the usual route to credibility. Had he joined the forum to participate and share his knowledge by answering questions, he could have put a link to his web site in his signature line and driven traffic to it
Others on here have done this, and we don't beat up on them.

gsa103

Correct, and had he done that, he would probably be lauded and welcomed.

Instead he's basically just spamming basic or largely irrelevant information trying to drive web traffic. This is targeted click-bait, nothing more. If he wants to refine and become a contributing member, there's nothing wrong with driving traffic to his site. But this is just spam.

I've seen nothing in his posts that would lead me to conclude that his site is a better source of bike information than wikipedia, let alone an actual source like Park Tool or Sheldon Brown.

Ghrumpy

While they are both good, they are far from infallible. I'd consider Park Tool and Sheldon Brown to be secondary or even tertiary sources, no offense. (I've found a few errors on Sheldon's site over the years.) Wikipedia at least provides bibliographies and sources to allow its content to be checked, and it can be corrected.

But back to Mr. Almanac. Cursory searches will show much of the information in his post to be incomplete, if not inaccurate. Allow me to offer some corrections and clarifications, which you are free to quote me on at your own risk:

Not exactly. Standards organizations do not "control" anything. They are collaborative, collative organizations that consult with companies and other organizations to compile and arrive at agreed-upon standards, based on what is in common use and suits engineering needs. They accredit standards but have no enforcement power.

The Sellers thread was the "original" American thread standard, presented in 1864. It had a 60° included angle, with flattened roots and tops. It was the basis of the USS standard thread. The SAE standard came later, and was the finer pitch version of the USS standard thread. The needs of automobile engineering precipitated the finer pitches of the SAE series.
The American SAE and USS standards were merged into and superseded by the Unified Thread series accepted by Canadian, British, and American standards organizations after WWII. The "SAE" designation is as obsolete as the "USS" designation, though its use persists. The ANSI is now the arbiter of the Unified Thread series in the USA. They are known as Unified National Coarse, Fine, and Extra Fine (UNC, UNF, and UNEF.)
Factually correct but incomplete. The measurement unit is important, especially since there is a Unified series #6 screw size.
And "it's" is a contraction of "it is" not a possessive form of "it."

No. A 1/4" x 20tpi screw or bolt would be USS series, as it's a coarse pitch. The "SAE" would be 1/4" x 28tpi. But see above.
And honestly, nobody I've ever known refers to such a screw or bolt as a "quarter twenty." Better to call it "one quarter by twenty tpi."

Again, factually correct, but incomplete.
The Whitworth standard was proposed in 1841. Italian standard cycle threads use the Whitworth thread form but none of the sizes interchange with any British ones, because Italians used metric diameters with threads-per-inch pitches. That is why, for example, Campagnolo headsets in Italian thread read "25.4 x 24F" instead of "1" x 24tpi" as the BSC ones do. Different thread forms, same nominal size and pitch.

It's not "British Standard Five" or "BS5," it's "British Standard FINE" or BSF.

Whitworth fasteners are too coarse to be useful for bicycle applications. So you will not likely ever find a Whitworth threaded parts even on British bicycles. Maybe a BSF, or even a BA (British Association) screw.
Because the Whitworth series were unsuited to bicycle needs, the CEI (Cycle Engineers Institute) standardized British bicycle threads in 1901, using the 60° "Sellers" thread angle, but with "Whitworth" rounded roots and tops, and the cycle industry adopted them pretty quickly (with few exceptions, Raleigh retaining their proprietary BB and headset threads until the bitter end.) Head sizes were not specified, because most threaded bicycle fittings are not nuts and bolts. So only the diameters and pitches were part of the standard. When CEI/BSC standard nuts and bolts exist, they tended to follow the Whitworth across-flats sizes as that's what people had in their toolboxes.
Eventually in 1908 the Fine series was added with the Whitworth thread form but the CEI standards were already in near-universal use by then, and the BSF series offered no advantage that made it worth changing the whole industry over to them.
Those CEI standards were updated and revised after WWII and renamed BSC (British Standard Cycle.) They have a 60° included angle, same as ISO and Unified thread fasteners, but with a slightly different thread form.

gsa103

I work in the optics industry. "Quarter twenty" is the standard terminology for a 1/4"-20 thread, which is the typical American thread pattern for an optical table. It's probably an industry specific thing.

Metric tables use M6x1 on a 25mm pattern. US tables are 1/4"-20 on a 1" pattern. And that 0.4mm difference is a NIGHTMARE!

dedhed

Honestly everybody I know and deal with calls it a "quarter twenty" or half thirteen or whatever, including the fastener vendors. If I'm ordering I'm saying, "Give me 500 half thirteen by 3" 304SS hex head cap screws" and get exactly that delivered.

SquidPuppet

JanMM

Got any soda pop to go with that popcorn?