Inch tools

[ckucia]

Specifically regarding taps, dies and drill bits, which I happen to be organizing this weekend.

"Metric" and "Inch" are pretty self explanatory. But I was wondering what the "correct" or "most correct" name is.

For "Metric", I've also seen "ISO" and "International Standard"

Inch I've seen "Inch", "American Standard", "Standard", "Imperial", "SAE", "US"

I'm just kind of curious if there's one term that's considered the most accurate before I label everything. I have some off topic reasons for wanting this beyond just my compulsiveness.

"ISO" and "SAE" would be easiest to write, although "Metric" and "Inch" are probably most recognized and practical.

 

[Prospecter]

+1. . . I was sorting in the shop, labling drawers, etc. and I had this same question today!

 

[ecotec]

Metric and SAE

 

[KnurledNut]

Unified Thread Standard (UTS)

Classified into:
Unified coarse (UNC)
Unified fine (UNF)
(and less common UNEF, UNS)

 

[darkzero]

I used to call it SAE or Standard as that's what everyone else around me called it when I worked in automotive. But I wonder why, SAE is Society of Automotive Engineers. They did not create "inch" measurments.

As said above, the correct term is UTS, Unified Thread Standard. But that's for threads, so taps & dies would apply, not so much for drills bits & socket/wrench sizes. USCS (US Customary System) is also appropiate. But no one ever says those & most people will have no idea what you are talking about. You'll see UTS in machining supply & hardware catalogs.

When I got into machining (hobby machining) is when I learned this. I now call it Imperial. Some may argue "Imperial" is not accurate but it's much more appropiate than "SAE" IMO. Seems like only mechanics say SAE.

Metric & Imperial is what I use but if I was labeling a tool box or the like I'd probably just put Metric & Inch instead of Imperial or MM & Inch.

 

[uscarry45]

From my. Understanding there are different metric standards. japanese standard britsh standard)

 

[ckucia]

Thanks everyone. I settled on SAE and Metric. But I used paint pens on plastic organizers - if I change my mind, a little solvent on a rag and I can do it over...

 

[Mechanical Noise]

No Whitworth?

 

[ckucia]

No Whitworth?

I looked that up, but I don't have anything yet in that standard.

Although I did discover I had a fair amount of NPT/NPS taps and a few dies...

 

[redwrench60]

I was raised calling it standard and metric.

 

[lardy1]

"Fractional" is a term I hear often.

 

[redwrench60]

For taps and threading it’s fractional and metric.

 

[Dave455]

For taps and dies it’s common to specify the actual thread, so while a thread may be a metric thread, there are several standards. ISO Metric is the most common (and in many countries you will find no others) however you can sometimes find older national standards.

If a designation has an “M” prefix (e.g. M8) rather than 8mm, that means it’s an ISO Metric thread.

American threads are often referred to as “National Fine / National Coarse” etc, but as darkzero pointed out above, since the 1950’s the threads have actually been “Unified” which are similar, but not identical in every case. UNF or UNC are the correct designations.

I wouldn’t use the term‘s “Inch” or “Fractional” since I’m in the U.K. and those terms might just as easily mean British Standard Fine or British Standard Whitworth, which are different again! Anything defined in inches would be “Imperial”.

 

[Grokew]

Call them "The Reds" if you use regular tools, "The Blues" if you use Duralast, Geardrive, or Duratech.

Or you can use "Freedom Units"

 

[Bockscar]

 

[Xcursion88]

SAE is a pretty common term that no matter drill bits, sockets, wrenches, taps/dies, SAE is definitely known as a fractional form...or inch as you called it.

If you just stick with SAE and Metric most everyone in the tool world will know exactly what you speak of

 

[pizza]

metric and continuing tragedy

 

[icthruu74]

Metric and “legacy inch based fractional measuring system”?
I just use metric and SAE, or sometimes fractional.

 

[4xdog]

I say inch, because it translates to friends around the world. SAE is very much an inside-America term, and even then I'll bet 95% of the country wouldn't hear "inch" if I said "SAE".

And I'd bet all the SAE standards are written around the metric system now anyway, dontcha think?

 

[Lassen Forge]

I use metric and imperial, and occasionally whitworth when that comes about...

 

[CS454]

I prefer a non discriminatory method of tooling.

Vice grips.

 

[mdrawde]

UNC/UNF and Metric coarse/fine for taps and dies. For drill bits and everything else, metric and imperial.

 

[64C10]

We’ve always used “standard” and “metric”. Still a lot of stuff we deal with that lives in that twilight zone outside of *current* UNC/UNF conventions, like 1”-14.

 

[ecotec]

How is anything only used by 3 countries (USA, Liberia and Burma) “standard”? That is the most arrogant thing ever.

Although… as they say… there are two kinds of countries… those that have been to the moon… and those that use metric…

Maybe this is justified arrogance.

 

[ecotec]

I replaced the head on my yard post lamp yesterday… a branch fell on the old one, and broke it.

I was disproportionately mad that the set screws needed metric Allen keys. Electrical, plumbing, heating and cooling… it should all be in SAE.

 

[PelicanPines]

Youtube machinist from Down Under uses Metric and Bananas

 

[darkzero]

Youtube machinist from Down Under uses Metric and Bananas

ThisOldTony says "dead nuts" when machining in imperial, for metric he says it's "spot on".

 

[speed bump]

I generally refer to inch hardware as SAE because that is the standard most inch sized fasteners outside of structural stick to. For ASTM standard fasteners I just call them structural hardware. this ignores the can of worms that is tubing and plumbing hardware though.

Metric I generally call metric but calling out hardware you have to be some what careful because there are several standards that are slightly different.

 

[larry_g]

I generally refer to inch hardware as SAE because that is the standard most inch sized fasteners outside of structural stick to. For ASTM standard fasteners I just call them structural hardware. this ignores the can of worms that is tubing and plumbing hardware though.

Metric I generally call metric but calling out hardware you have to be some what careful because there are several standards that are slightly different.

I've said it before, Standards are so important everyone should have their own.

 

[64C10]

I don’t really have any issue with either system, but I believe there is a special place in hell for engineers that take an existing drawing and convert it to metric for no good reason. Did a job a while back tying a new “upgraded” pump into a pad that was originally poured in 1928…..after all the conversions EVERYTHING was off by 1-3”. Then the Chinese pump with an impeller made of Reynolds Wrap lasted less than a week, and we got to rip it all back out and put the “obsolete” Gould’s right back in.

 

[goldtang]

I use metric and imperial, and occasionally whitworth when that comes about...

I use the same

 

[CS454]

Youtube machinist from Down Under uses Metric and Bananas

Righto guys...

 

[cherrybomb]

Metric and inch works for me,way back in the day,our country thought about converting to metric like the rest of the World.But our attitude said the World should come to us.We have been behind ever since

 

[finn]

If you look at the SAE handbook, or any modern SAE technical paper or other publication, any and all calculations, tables, and references are in metric units.

It’s been that way for well over twenty years.

 

[Mechanical Noise]

Inch and metric would be my choices. Simple and clear. US customary would work if "inch" seems too concise.

SAE means Society of Automotive Engineers. Today, an auto engineer would specify metric threads. And I have no idea what SAE drill bit sizes would be. Inch size bits are most clearly sorted as fractional, number and letter bits. Also, we've had metric spark plug threads for about 100 years. So SAE didn't necessarily mean "inch" even in 1920s USA.

Imperial means British standards to me. Like Whitworth and BSF and CEI and BA threads.

Any description with American Standard, Standard, US Standard and US threads could be misinterpreted these days. Confusing!

 

[ckucia]

I'm familiar with metric, but inch fasteners and threads aren't exactly ancient. My 2001 Cherokee 4.0 is all SAE inside the block. Don't know if new ones are still built that way.

My biggest problem with metric is it's lack of relationship with humans. Foot being the obvious one but an inch is also about the end of your thumb and a cup is about what your cupped hands hold. Very easy to internalize.

A meter is roughly a yard, which is about what outstretched arms measure , but generally measurements that large I don't use. A mm is about fingernail thickness but that also isn't much use.

For just general day to day human guestimating measurements, feet and inches are single or maybe double digit multiples where cm and mm are tens, hundreds of thousands. The math is easier but relating is more difficult. It's somewhat irrelevant if using a ruler, but when you're just looking and estimating it makes s difference..

I wish the committee that developed metric had picked units in common. They intended to derive them from nature but ended up fudging most of them anyhow. If they had made a meter exactly a yard, for example, then a foot would be 1/3 meter and an inch 1/36. A lot easier to do in your head and convert back and forth and then the new units would have been simply a preference rather than being virtually incompatible.

 

[cannuck]

Since I have been a VW guy for so long, I often call my threading tools in the front row of my tool box "ISO", or just "Metric". The stuff that lays down in the pipe drawer of my machining area tool box I refer to as NPT and NPS. The back row with fractional inch sizes I usually call "Bassakcwards" or UN (for Unified National - not United Nations). The stuff in my aviation area I simply call AN. Being generally an *******: I delight in telling people when they call their inch tools "standard" that since the entire world uses metric, only your metric tools are in any way "standard"

 

[JradM]

I've never heard the term "inch" used that way before. Maybe I've been living in a cave. I agree that it's obvious what it refers to - but I've only heard SAE, standard, imperial and fractional.

 

[Lucid Moments]

I just call them Metric and useless.

 

[tamaraw]

I use metric and imperial.

Americans who don't like the metric system often call their own measurements "standard" but this tends to be older folks and/or people who work in specific industries that only use imperial. It's a dumb name imho because there is absolutely nothing standard about it without a frame of reference for your application.

I have also heard "inch" or "fractional" occasionally and while it does get the point across and kind of make sense, I believe it is more informal terminology.

Calling stuff "American" or "US" also gets the point across but is not very accurate. Most of the non-metric measurements used in the US are just normal imperial measurements taken from the UK and also used in Liberia and Burma. Only a small subset of these non-metric measurements are actually American. For example, NPT (vs BSPT) and several liquid measurements like the US quart (vs UK quart) or US gallon (vs UK gallon).

As you can see, saying imperial isn't technically correct for every non-metric unit in the US but it is true for the majority of them (or even all of them depending upon application/field).

SAE also get thrown around very commonly in automotive applications and on corresponding tools sold in the US but I believe is less prevalent in other fields.

For metric, I would definitely avoid using ISO because there is also DIN, JIS, and ANSI which are different standards. If you had a set of tools for working on Japanese cars and another for German cars, you could call them JIS and DIN to differentiate the selection of sizes but I wouldn't go around calling everything ISO instead of metric because they are not totally interchangeable. Scroll to the bottom of this article to see the differences: https://grassrootsmotorsports.com/articles/understanding-metric-hardware/

Long story short, while there are issues with a lot of these names, they will still get the point across in most situations. If it's for personal use, go with whatever makes you happy. If it's for shop use, go with whatever is most commonly understood in your particular field