Metric vs. SAE standard tool usage?

[M635_Guy]

Home and auto DIYer, and it's been a very, very long time since since I needed SAE. I'll call it 95% metric for me...

 

[Pexto]

I have a 2023 Skidoo snowmachine, and I've kind of been assuming that everything on it was metric or Torx. But just the other day I changed the gearcase oil. Looked at the drain plug and grabbed a 5mm hex. Didn't fit, too big. Tried a 4mm knowing damn well it wasn't a 4mm, Yep, way too small. Tried a different 5mm. Still too big. WTF?

Thought about it for a few seconds, then tried a 3/16 hex. Perfect fit. There are two plugs on this chaincase that take 3/16 hex; everything else on the machine seems to be metric (or Torx). Weird.

 

[charger 73]

At home 90% metric , at work (aviation) all sae.

 

[threewood]

I voted 70% sae.

Most of my tinkering is on my 60's era Plymouths. But our daily drivers are a GM and Nissan, which are metric. I do regular maintenance on them and don't have to work on them too much.

We built a new shop to store my cars so the sae tools went into the new shop and the metric stayed in the garage for the most part, Although I did leave the spare sets just so there is overlap. Not to mention a good reason to buy more tools so I had sets in both places.

 

[dnschmidt]

I'm into old cars that were made before "Metrics" came in to corrupt our American standards.

If it's American then why is it referred to as IMPERIAL? Might have your COO wrong on this one.

 

[CGarage]

If it's American then why is it referred to as IMPERIAL? Might have your COO wrong on this one.

You mean, Communist and Imperial

 

[dnschmidt]

The metric system is a FRENCH invention. Now if you want to be picky you might want to call them Socialist but they are decidedly not Communist. I've been to France many times and use to work for a French company: STMicroelectronics.

 

[NFH2740]

Major manufacturers maybe. Most of the short lines still use standard.

Martin

And who produces the majority of units? The majors.

 

[speed bump]

Mostly American customary units technically a lot of structural/non SAE stuff. Metric is mostly new equipment at work and vehicles at home. The worst is when some ******* French or British company can't use standard pipe fittings.

 

[DrinkMan]

The vast majority of time is working on our cars. The old Triumphs & Lotus Elan are not metric but they don't need as much effort as the other European cars that are a lot more complicated (resulting in more issues....especially the Germans) and metric.

 

[CGarage]

The metric system is a FRENCH invention. Now if you want to be picky you might want to call them Socialist but they are decidedly not Communist. I've been to France many times and use to work for a French company: STMicroelectronics.

My post was in jest.
I have lived in France and spend time there every year. They are excellent engineers.

 

[msharley]

Hello.
It is my first post on here.
Want to hear how do people in U.S. think about subject.
For me in Japan, it is 99% Metric in any situation.
Please let me know!
Thank you!

Welcome to GJ....

Should have included the WENTWORTH for our British Enthusiasts!

 

[ZRX61]

SAE, metric and British Standard for me.

Ditto. & BA

 

[Kevin J.]

So, it looks like this metric system might catch on hey.

 

[F-22]

Nothing but metric here in Europe for all my life - until I got an old Harley Shovelhead and it's so annoying that I need separate tools for it. And not just the tools, but the coarse SAE screws look so absurd to me, with that kind of pitch it's no wonder these bikes are infamous for loosing screws. The SAE fine threads look kind of like normal metric threads.

And when I took the gearbox apart, the studs that hold the side cover came undone - even more absurd here, they used a coarse thread in the alloy housing but a fine thread for the nut. Does this maybe have something to do with holding better in the lower quality alloy casting? That's how I'd try to explain it to myself, but it still seems like such a waste of resources to make stepped studs like that (compared to just using off the shelf rolled all-thread cut to length), and if all the rest of the world could use finer metric threads in aluminium castings it's probably not something Harley had to do either.


Too much work to bother with it, but I'm sure that if I'd helicoil all the holes with standard metric threads, things wouldn't loosen up as much anymore. But I really don't want to mix both standards on one bike.

 

[Citation]

I'm mostly metric and much of my design life has been based on metric. Ironically, the most expensive things I've worked on (some robotics and gas turbine generators) were SAE. The turbines makes some sense as they were based on aircraft engines. The robots surprised me but in the US it's just easier to source SAE sized bearing and gears. Yes, metric can be had but the range so sizes when you need specialty parts is better when you open the SAE section of the catalog.

I will say that I think the SAE size jumps are more logical if you think about it in absolute terms. A smaller set of SAE sizes covers the same range of fasteners. I think the primary reason is metric tends to want to jump sizes 1mm at a time. So we end up skipping a lot of metric sizes (7, 9, 11 mm) and favor the sizes near them (8, 10, 12). Thus 6 wrenches in my box even though it's possible 3 have never been used. Consider the range 8-14mm. If you have a Japanese car you will use 8, 10, 12 and 14 while skipping 9, 11 and 13. But if you have a euro car you might need that 13mm and a 15mm. 9 and 11 still seem to be there just to complete the numbers. In about the same size range SAE has 5/16, 3/8, 7/16, 1/2 and 9/16. All would be reasonably common in an older car and, if you knew the car/tractor etc was SAE you wouldn't wonder if this mfr used 7/16 or 15/32nds. Thus I need only 5 wrenches to cover the same range as 6 commonly used (and 8 total) metric wrenches. Heck, recently I wanted to buy a cheap wrench set to deal with bike wheels when going on vacation. I was surprised that most very cheap HF or Walmart metric sets skip 15mm! Yeah, skip it if you are working on a Toyota but 15mm is one of the most common faster sizes on basic bikes. It's the standard axle nut size as well as used for unsealed wheel bearings and pedal. But I found many cheap wrench sets skip from 14mm to 17.

 

[AA/FC]

I use whatever the fastener that I am currently working on requires... I don't get to decide which tool to use, the fastener decides that for me.

I have a full set of metric wrenches and sockets, and a full set of SAE wrenches and sockets. When I buy new tools, I ALWAYS buy both the metric and SAE version of whatever it is that I am buying. Always! I never buy just a metric or SAE set of anything.

 

[Garcky]

In my drawers, it's SAE on the left and Metric on the right. I use both. That's how I've always arranged my tools.

 

[dnschmidt]

When I was selling TOPTUL one of the members here , I think it might have been SK Farmer but I'm not sure, got on my *** for not selling SAE tools. My response to him was that I didn't want to die with them because I couldn't sell them. My point is that most people that need SAE already have a toolbox full of them and that most of them are old bastards, like me, that bought their last SAE tools twenty years ago. It would be interesting to me to find out what percentage of new wrench and socket sales are SAE vs. Metric. I'm thinking it's probably in the 10% SAE and 90% Metric range. As charger73 mentioned aviation seems to be the last bastion of SAE likely due to the fact that airplanes last forever. I wonder if the newer planes use metric or if the latest versions are still SAE.

 

[boom_bap]

Any puller I've come across has been SAE. Idk if people just use metric anyways, but theres a need for both, even if you only work on cars with metric here in USA.

 

[bigfunwmu]

Any puller I've come across has been SAE. Idk if people just use metric anyways, but theres a need for both, even if you only work on cars with metric here in USA.

My Snapon and OTC pullers are SAE, but the Schrem and Gedore pullers are definitely metric.

ETA: my BETA kit is metric too

 

[82355]

And who produces the majority of units? The majors.

Our Demco sprayer has standard hardware.
Our Brent grain carts have standard hardware.
Our Big John saddle tanks have standard hardware.
Our Sunflower disc has standard hardware.
Our Buffalo box scraper has standard hardware.
Our Westfield augers have standard hardware.

Even this John Deere field cultivator has standard hardware.



Our three newer John Deere tractors, the combine, and the planter use Metric, but that is not the majority.

Martin

 

[silkman]

I'm approaching 50 and have never touched a SAE fastener in my life. Cant imagine having to buy double the tools you guys in the us of a have to.

In my dads tools I've found a 1/4 sae socket set. Quality is craptastic, 80s Taiwan stuff, worst ratchet I've laid my hands on. Tried to take a photo but my phone exploded, thats how bad it is but I've kept it just in case.

<--Athens, GR

 

[Meursault74]

I'm approaching 50 and have never touched a SAE fastener in my life. Cant imagine having to buy double the tools you guys in the us of a have to.

In my dads tools I've found a 1/4 sae socket set. Quality is craptastic, 80s Taiwan stuff, worst ratchet I've laid my hands on. Tried to take a photo but my phone exploded, thats how bad it is but I've kept it just in case.

<--Athens, GR

It's a big conspiracy to sell us more tools .

I don't care at this point. It is what it is over here.

If you're working on a modern car and need specific tools just for that then there is no need for the SAE equivalent, so you don't need to buy both.

 

[Rusted Nut]

We have a Toyota, a Jeep, an F-350, and two Harleys. Pretty much 50/50. Toyota and Jeep are metric, F-350 is SAE, Harleys are SAE except for the Showa forks which are metric.

 

[dchawk81]

A semi is a mixed bag of SAE and metric if it's modern. The drivetrains, brakes, and suspensions are usually legacy designs from companies like Meritor. Air fittings and tubing is SAE.

You really can't away with all one or the other.

I'm considering one final upgrade to Proto SAE and Metric wrenches because they seem to be one of the last professional lines to offer 6 point.

 

[82355]

A semi is a mixed bag of SAE and metric if it's modern. The drivetrains, brakes, and suspensions are usually legacy designs from companies like Meritor. Air fittings and tubing is SAE.

You really can't away with all one or the other.

I'm considering one final upgrade to Proto SAE and Metric wrenches because they seem to be one of the last professional lines to offer 6 point.

Snap-on Store

shop.snapon.com

Martin

 

[Hannahranga]

I've got a slew of old stuff...tractors, old equipment, and cars. Also have newer vehicles and mowers. But worst I have 80s GM vehicles...so 50/50 for me! Haha It always amazed me how that transition was in the 80s for GM, especially. Everything on the car was metric...then you got to the drivetrain...most of it was still standard, except for a few bolts! Haha
Joel

My Landrover is like that, completely metric other than 3 of the prop shaft flanges (4th is a guido and metric). Conveniently they also **** to get a socket on anyway so you end up buying the relevant propshaft tool even if you've got SAE sockets and spanners.

Does seem fairly standard for LR, they kept their series Landrover gearbox's Whitworth despite the rest of the car being AF fasteners.
Conveniently the propshaft bolts are the same as my disco (not a bad run for a special tool considering it works from the first series 2 all the way till the last of the classic defenders)

 

[gtae07]

I wonder if the newer planes use metric or if the latest versions are still SAE.

Aviation (at least US companies) still use inch-based hardware and material. The standard hardware (bolts, washers, nuts, rivets, bearings, etc), fittings (hydraulics, pneumatics, etc), raw materials (tubing, sheet, rod, and more) were all developed, tested, and standardized decades ago. All the test data is built around those sizes, the tooling for hardware is built on it.

The only place I really see metric hardware is on "non user serviceable" equipment, or imported light aircraft. I have no idea what Airbus, Embraer, etc. use.

 

[charger 73]

Airbus and Embraer use sae.

 

[Hannahranga]

Airbus and Embraer use sae.

You know if I was a young German/French apprentice starting my first day at an Airbus factory I suspect I'd be a smidge shocked to learn that.

 

[Citation]

Airbus and Embraer use sae.

I assume that's just for engines/other parts from US suppliers vs across the board. Is Rolls Royce SAE (or Whitworth)?

 

[Dave455]

I assume that's just for engines/other parts from US suppliers vs across the board. Is Rolls Royce SAE (or Whitworth)?

Actually, no!

Pretty much every fastener on an Airbus is SAE, or rather Unified, to be precise! The only ones that might be metric would be bought in units, such as IFE etc

The entire industry uses Unified, so anything else would be non standard. I can even think of a couple of Whitworth threads on the A330 - they’re probably on the A350 too!

Rolls Royce engines, like most British built products, were Whitworth (or more usually BSF) until the late 50’s, then changed to Unified.

Once an engine has been produced, I believe RR are reluctant to change the fasteners, so I think every Dart (for example), from the late 40’s to the 80’s, has BSF/BSW/BA fasteners. Every Trent, has Unified.

 

[Al Borland]

Work, I'm usually in old factories/facilities with 95% SAE. Home, most everything on my car or truck is metric.

 

[ecotec]

Work, I'm usually in old factories/facilities with 95% SAE. Home, most everything on my car or truck is metric.

This… I don’t do just factories, though. In electrical, we are still more than 95% SAE…

 

[carmantl]

Structural Steel Ironworker here. Everything is SAE!

 

[carmantl]

Oh, I live in the USA.

 

[BlakeTheCarGuy]

When I voted a few weeks ago I chose the 90% metric and 10% SAE. At work I use almost exclusively metric but occasionally do have a need for SAE. At home I use both. My dad has a Freightliner that’s all SAE there is also a good bit of SAE on our 1994 Ford Econoline and 2001 Jeep Cherokee. Every other car is metric though.

 

[belvedere]

there is also a good bit of SAE on our 1994 Ford Econoline and 2001 Jeep Cherokee.

I had a 98 Cherokee and remember it having a mixture of SAE and metric. Made it a little frustrating to work on!

 

[CGarage]

It seems in the US, older American automobiles made before the year 2000, industrial / plant and electrical applications are still largely SAE.