A glimmer of hope

[mklotz]

Post deleted by author

[Frank S]

Back in the day while working on Cat equipment it was pretty easy to tell which system a particular machine was built under by simply checking the serial number if it was an older machine made domestically it was imperial everything made off shore it could have been a mix if it contained domestic components later machines became more metrically .leaning until virtually everything became metric. However it was not uncommon to find fasteners clearly marked in metric grades but with US imperial threads and diameters replacement bolts usually wound up being Imperial grade 8 since the only way to buy them from cat was by serial number of the machine. Now all late model cat equipment is full on metric but there are still and probably always will be many propitiatory fasteners seals o rings and other parts which will never be true to either system but a combination of both just so you have to buy your replacements from cat

[Toolmaker51]

Back in the day...fasteners seals o rings and other parts which will never be true to either system but a combination of both just so you have to buy your replacements from cat

Yes, most assuredly. It screens out certain wannabe mechanics; to capture a lyrical phrase "...cant' find what I'm lookin' for".

Only for some folks...We know how to measure, read a catalog and order! Anyone else have a McMaster-Carr sized set of web bookmarks?

[Frank S]

Yes, most assuredly. It screens out certain wannabe mechanics; to capture a lyrical phrase "...cant' find what I'm lookin' for".

Only for some folks...We know how to measure, read a catalog and order! Anyone else have a McMaster-Carr sized set of web bookmarks?

Maybe not that large yet. my bookmarks runs 5 folders deep my other bookmarks folder has so many pages and folders in it that it is easier to just type in what I am looking for in the browser and hope to not have to sift through 1000's of erroneous do nothing mean nothing unrelated web pages
It's my C drive where I find most of what I need, since I have nearly as many folders running sometimes 10 sub folders deep, as Microsoft has line codes for their OS

[Toolmaker51]

.......There are seven different barrel sizes used in the USA, with the size being dependent on the contents. Their names and metric equivalents are as follows: US cranberry (95.5 liters), US dry (115.628 liters), US liquid (119.24 liters), US federal (117.348 liters), US federal proof spirits (151.416 liters), US drum (208.4 liters), US petroleum (135 kg.), US petroleum statistical (158.99 liters).

After all, if one definition of a unit is good, seven must be seven times better.

One stands out, a key to the problem By the time smaller drums were measured, too plastered to hold out for the largest!

I'm comfortable enough twixt imperial and metric, using them when advantage suits.

The case for changing navigation units though will be a difficult sell. "60" is their mistress. Even the US Navy still shoots sextant daily and gyro vs compass in 1/2 hour intervals underway for dead reckoning. The divisions of a 24 hour day are an important contributor. https://en.wikipedia.org/wiki/John_Harrison Harrison essentially dedicated his life to the solution.

All of it verifies electronic results - NOT the other way around. Relation of time - speed - distance inescapably points out the wonder of algebra.
The instant results of 360' circle, arc to time, the 6000 foot mile, latitude and longitude in same unitary combination are critical to avert collisions and minimum closest point of approach by every seagoing vessel, just like English is required in all ship to ship communications regarding right of way.

Marv points out the true nautical mile of 6076.12 correctly. Habit on my part quoted 6000, and both are correct at specific times. Until recently lat & lon couldn't be measured so closely in a vehicle subject to wind, current, waves. The 'missing' 76' feet are absorbed by set and drift nautically, averaging out well between point of departure and arrival. And rhumb-lines are still stepped off with dividers.

[mklotz]

The nautical mile (6076.12 ft) is a good example of a useful occupation-specific unit. Because it was originally made equal to the length of an arcminute of latitude, a navigator could easily read distances off his charts marked with latiude and longitude. However, since the earth is an oblate spheroid, the length of an arcminute of latitude is not constant so the unit value was indeterminate. Given the utility of the unit though, it was incorporated into the SI system and is now defined as exactly 1852 meters. The unit of maritime speed, the knot, is also included in SI and is set at one nm/h (1852 m/h).

The trick with such useful derived units is not to let them loose in the world at large. Use of the nautical mile is largely confined to the areas of nautical and aeronautical navigation. Nobody is putting up road signs showing distances in nm, nor are drapers selling cloth by the milli-nm.

Chalking the number of times a sheet of steel has been through the rollers is probably useful in a rolling mill. But once you start selling sheet steel forget those chalked numbers and list it by thickness using the commonly accepted measurement system (which means metric most everywhere).

[MiTasol]

Also, "micrometer" used as a dimension in a machine shop setting can be confusing given that the primary tool in that venue has the same name.

But ONLY in the USA where some clown/committee with the power to do so in a fit of petty bastardry (or just to prove he/they had POWER) decided to misspell all metric measurements and did not have the brains to realize that the proper spelling of metre and meter automatically indicates the nature of the subject - metre for a measurement and meter for a measuring instrument.

Obviously the same clown/committee decided that the proper spelling of Aluminium (again as used in every country except the USA) was another way to deliberately create confusion and prove how powerful he/it was.

On the other hand when it comes to total METRIC stupidity then Australia takes the cake.

The first formal thread system invented was the British Whitworth system and was a great leap forward for mass production and ease of repair.

Early on the Americans also used Whitworth but soon realized that the 47 degree thread angle was not as strong as a 60 degree thread angle and created the American National Course (ANC) threads using the British TPI for most threads but with a 60 degree angle. They also recognized that the British head sizing sucked and fixed that problem.

During WW2, with lend lease, hardware interchangeability became a massive problem and the British and Americans jointly decided to address the problem with a new thread combining all the best features of both the Whitworth and ANC systems (and the related ANF and BSF systems) and created the Unified threads in 1947. Both countries transitioned as quickly as possible.

In November 1946 (71 years ago) the Brits classified Whitworth as Inactive for new design.

By 1952 Whitworth had disappeared from the vast majority of British mass produced products.

Sixty five years later in Australia Whitworth is still the preferred thread for many people and industries and small Unified hardware such as 8-32 and 10-32 is extremely hard to find in shops. Using Whitworth in an export item is a great way to destroy an export market as anyone outside of Australia will instantly recognize because no-one outside Australia has Whitworth hardware and tools.

In 1947 Australia signed the Metre Convention making metric units legal for use in Australia, and in 1970 passed the Metric Conversion Act with the aim of making the metric system the sole system of legal measurements in Australia.

By 1974 every school in Australia was teaching metric only. This means everyone over the age of 49 was schooled exclusively in metric and those as old as 61 received some schooling in metric. Early on it was illegal to sell goods in inferial (a great word Marv) but now it is legal to use both and many companies owned or managed by troglodytes have gone backward to inferial. The next time I am in any of several large clothing shops I shall photograph a typical trouser size label INCHES in big letters and cm in a much smaller font. I do not shop in those stores any more. And no, these are house brand products, not name brand products imported from the US or UK.

But getting back to threads and other steel products.

Australia loves Whitworth so much that they have recently introduced the 13mm bolt. When you measure it up it is 100% a 1/2 inch Whitworth bolt. No other country has a 13mm bolt as a common standard, let alone one that is a 100% bulls**t size.

When Australia started to manufacture Metric bolts they decided to use the head sizes of the nearest Whitworth size bolt.

When you buy an ISO standard tool set you do not get, as an example, an 18mm spanner because an 18mm tool is not used for any International Standard metric bolt.

In Australia you must buy the 18mm spanners and sockets because Australia, unlike the real world, uses the 18 head size. Naturally when Australia exports "metric" goods that means that when the customer goes to assemble or maintain or repair the product he/she does not have the right tools in their tool kit. Another great way to destroy an export market as anyone outside of Australia will again recognize.

And then we get to tubing - I will cover that in a few days time but the Australian tube diameters are, like Whitworth, from an archaic British measurement system. I have purchased REAL metric tubing from the US for several projects recently because it is not available here. Another great way to destroy an export market.

[MiTasol]

For much of the design work that I do, I prefer to work in the metric system. Once you're in CAD, it is just a number, the system you're using, imperial or Metric doesn't mean much.

Even in the machine shop it is just a number but troglodytes in some countries cannot realize that.

Two examples

In WW2 GMH in Australia started to manufacture the British deHavilland Gypsy Major engine under license. To quote the company history "GMH War Record" they totally redid all the blueprints and converted 41,500 dimensions from metric to imperial, many to five decimal places.

Why?

Surely it would have been far more cost effective to train the machinists and inspectors to use metric measuring tools and gauges - especially since the majority of the production and inspection staff were women and other new hands with no previous experience in manufacturing who had to be taught the absolute the basics of using their tools anyway. Much of the sizing was done using go-nogo gauges that are "just a size".

In the USA Packard did the same with their license built Rolls Royce Merlin engines - 100% new drawing in inches to replace the Rolls Royce metric drawings. What a waste of skilled labour.

[NortonDommi]

Early on the Americans also used Whitworth but soon realized that the 47 degree thread angle was not as strong as a 60 degree

Actually Whitworth has a 55 degree included angle.It should be noted that Joseph Whitworth designed his thread at this angle for several reasons, the most obvious is the materials in use at the time, mostly cast iron of one sort or the other and the head sizes were made at the ,(large to us today),sizes so as to distribute the load, the thread also has rounded peaks and roots for strength, Whitworth is actually a very good thread form. If you do some homework you will find that the ISO metrickery size threads are very closely related to Whitworth. As for common metrickery sizes those damn French who came up with it use 7,11,15 and other weird sizes,(probably a 13 in there too), and yes you do need 16,18,20mm size spanners and sockets to work on their stuff. They also label their engines backwards so there is no hope for them.
As someone from the civilised side of the ditch I would love to hear more about this new sizing system in Australia, perhaps some French consultants were brought in to advise?

[MiTasol]

I also find working in fractions with Imperial measure is a doodle unlike metricery.

Tell me - where do you get micrometers and verniers that read in 64ths, 128ths and 256ths

And the Pyramids were built in cubits not feet and inches. The local Egyptian cubits in use on that project to be more accurate given that no two areas cubits were the same.