Aaagh!!! I’ve been there, got all the tools, under the car, in position, and “S*&T – Its Imperial”.
So what is a 10mm socket equivalent? The equivalent imperial size of a 10mm socket is a 3/8 socket.
Imperial sizes are known as SAE (Society of Automotive Engineers) or Standard. Metric sizes, also known as SI (Système International), from the French International System.
So what’s an Imperial size (SAE)?
Imperial size fasteners are measured in inches or fractions of an inch, examples are 3/8 inch, ½ inch, 7/16 inch, etc.
The info-graph below matches the closest equivalent Standard SAE to Metric sizes, I’ve colored some of the more popular sizes.
Whats a Metric size (Si)?
Metric size fasteners are measured in mm and the sizes are known as M-, examples are M8, M10, M12, etc.
Fasteners are described by their thread diameter, not the head size. So in the case of an M8 bolt, the diameter of the bolt measures 8mm, but the bolt head will require a 13mm wrench or socket to drive it.
A Brief History Of Metrication
The whole world used the Roman-based Imperial measurement until 1795 when Paris was the first district of France to adopt the metric system, I knew the French were to blame.
The adaption wasn’t smooth, many understandably objected. Metrication offered great advantages and over the next two hundred years, it eventually spread right across Europe.
Japanese converted in the 1920s and so the cars that landed in the USA were built using metric nuts and bolts.
In 1971, Ford USA began the process of building American automobiles using metric sizes. It also led the charge with General Motors and Chrysler by setting up the North American Automotive Metric standards (NAAMS).
The NAAMS set to standardize the industry, making life much easier for part suppliers and creating synergies with European auto companies.
Britain started the process of metrication in the mid to late sixties and by 1975 cars were being built with a mix of metric and imperial sizes. Britain hasn’t fully embraced metrication, their system is a mix of both. But the manufacturing industry uses the Si measurement as its standard.
The 70’s mechanics needed two sets of tools, metric and imperial. Today, a mechanic only needs metrics, unless of course, they’re working on classic or vintage cars.
Other fastener industry standards are:
- ANSI – American National Standards Institute
- ISO – International Organisation for Standardisation
- DIN – Deutsches Institut für Normung
- JIS – Japanese Industrial Standard
Wrenches I’d Buy
Most of my wrenches and sockets, I’ve had for years. If you buy a good set, you might never need to buy another. I’ve listed my favorite wrenches, sockets, and ratchets as well as a brief outline as to why I like them
Good, useful tools, don’t need to be expensive. Every DIY’er needs a set of ring wrenches. You never know what size you need till you need them, so the TEKTON Combination Wrench set comes in different options.
A 9, 11,13, and 15 pieces, I’d just go ahead and get the 15 pieces, they’re all good value, solid kit. Nothing worse than not having the right size wrench that sends my day upside down.
The wrenches are made from vanadium steel with a mirror chrome finish, and that’s pretty standard.
The reason I like these wrenches, they’re 12 point ring so they grip the walls of the fastener and not the edges, that makes a difference when your opening stubborn nuts and bolts. Spinning a wrench on a nut is a real pain in the jacksie, cos now the job just got bigger.
The other reason I like these wrenches is the packaging, it’s actually useful, you can put them straight into your toolbox and they remain organized and easy to find and replace.
I like that the wrench size is stamped clearly into the body, my eyesight isn’t as good as once it was, some of my wrenches are a little harder to spot lately.
The offset angle of the wrenches is also pretty standard and what you’d expect from good kit.
Racheted Wrench Set I’d Buy
Ratcheting wrenches are God’s gift to mechanics. When a job is going really well I’m always suspicious, because I know every job has one awkward fastener.
You know the one, really confined, turning just a hair at a time….sole destroying. I bought myself a set of ratcheting wrenches, years ago, still, have them, and still working. I don’t use them every day but when you need them you need them if you know what I mean.
Anyway, I’d buy the GEARWRENCH, 12 Point Ratcheting Wrench it’s what I call a good kit.
It covers all the most popular metric sizes you’ll likely need in ratcheting wrenches. 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, and 24mm .
The features I liked the most are the fine ratcheting positions (72 teeth), just 5°, and your pulling, most including mine need more room to engage.
Chrome finish with the wrench size stamped, I like that, makes them easier to read. The ratcheting box head is slim yet strong, allows you to fit it into tight spaces, just what you need in a ratcheting wrench.
The best bit, they’re covered by a lifetime warranty.
Check out the Amazon link below.Amazon Gearwrench Tools
Socket Set I’d Buy
I love DeWalt, their kit is built to last. I have lots of their tools, a drill I’ve had for years still going strong, so I know it’s good stuff.
Every household should have a decent tool kit, it’ll pay for itself many times over, guaranteed. I know this because our kitchen sink tap came loose, my wife called the plumber, his call-out rate was almost the price of this set. Apparently, I was asked several times to take care of it.
The thing I like about the DeWalt tool kit the solid case is pretty standard but very useful for keeping everything together.
It’s the full range of ratcheting sizes, from the smallest 1/4 inch drive to mid-size 3/8 and the heavier duty 1/2 inch. The ratchets are premium quality chrome 72 teeth with 5° arc, and well throughout thumb controls.
The set is 192 pieces in total with a huge range of sockets, that cover metric and SAE, both deep and regular profiles.
There’s an impressive range of ratchet extensions, converters, and swivels. This allows you to mix and match all three sets, you’ll never be wanting. There is a small selection of the more popular size Torx sockets and Allen keys.
You won’t be surprised, it comes with a lifetime warranty, I love it!
Check out the Amazon link below for hot deals on DeWalt kit.Amazon DeWalt Tools
What Size Is Between 10 And 11mm? The SAE Imperial size in mm is:
- 3/8 Inch wrench measures 9.53mm
- 7/16 Inch wrench measures 11.11 mm
Is 10M The Same As 10mm? No, 10M or more commonly written M10 is the diameter of the threads, fasteners are always referred to by their thread diameter. An M10 fastener would have a 17mm head and therefore require a 17mm socket or wrench to tighten.
If you’ve ever considered becoming a mechanic check out this post – Is it worth being a mechanic. And if you’ve ever wondered about rates of pay you can check out job vacancies and rates of pay here on Jooble.org.
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- About the Author
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write fluff-free articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.