Metric nut sizes

[NDIHC]

If you work on most Asian cars you need 8, 10, 12, 14, 17, 19, 21 and 22. Sometimes a 15 on inner tie rods when doing alignments. If you work on Nissan, anything goes. They use 13, 15, 16 and 18 along with the other ones the other asian cars use, and occasionally an 11 will come about. Domestics used to use 5.5, 7, 8, 10, 13, 15 and 18 for the most part but I haven't worked on domestics for 20 years, other than my 90s pickups and some GM cars from the 80s and 90s. European cars use any and all sizes it seems. So it all depends what you work on. There is a use for pretty much any size from 5.5 through 24, 27 and 30.

 

[wore out]

If you work on most Asian cars you need 8, 10, 12, 14, 17, 19, 21 and 22. Sometimes a 15 on inner tie rods when doing alignments. If you work on Nissan, anything goes. They use 13, 15, 16 and 18 along with the other ones the other asian cars use, and occasionally an 11 will come about. Domestics used to use 5.5, 7, 8, 10, 13, 15 and 18 for the most part but I haven't worked on domestics for 20 years, other than my 90s pickups and some GM cars from the 80s and 90s. European cars use any and all sizes it seems. So it all depends what you work on. There is a use for pretty much any size from 5.5 through 24, 27 and 30.

I'm GUESSING that a guy with the handle "caterpillar guy" MAY be working on stuff with nuts considerably larger than found on "Asian cars"?

IF that's true I don't know how any of us could advise him, IF he doesn't know the common sizes on stuff he works on how could anyone else?

 

[NDIHC]

I'm GUESSING that a guy with the handle "caterpillar guy" MAY be working on stuff with nuts considerably larger than found on "Asian cars"?

IF that's true I don't know how any of us could advise him, IF he doesn't know the common sizes on stuff he works on how could anyone else?

Well, he just asked about metric sizes. Said nothing about what he's working on. Maybe he likes caterpillars but has to work on a Kia occasionally. I take as he's asking because he might have to work on something metric at some point. He asked what he should have basically in sizes under 30mm. And that's pretty much what most answers have been about. I didn't "guess" about his question. I just answered the question he asked in the context in which he asked it. He also later added that he mostly works on his combine but would like to have tools for future car and pickup repairs.

 

[caterpillar guy]

Yes I do like the old Cats the Family has 2 of them a D-4 Grandpa bought New in the 30's and a NO6 Traxcavator .Basically a tracked loader with a 2yard heaped 1.5 yard struck. I have used both of them to moldboard plow with. Some days I think I would be better off going back to them. Less compaction and cheaper on fuel. Would need to load them all the time to work ground at my brothers places and mine across the road from dad's. Yes I was wondering if there were some sizes not used enough to justify buying. I guess it is not so such that I might just as well acquire all of them up to the 30mm. Thanks and the metric is pretty much a new world for me in wrenches. OR more like wenches. Such a pin with having to practically retool at my age rather than just use one set of tools. Nothing runs like the sound of an old Cat just purring along in the field.

 

[Jim.ME]

" I guess it is not so such that I might just as well acquire all of them up to the 30mm."

That is your best idea. If you don't you will find you need the one you don't have. To increase your pain with this I suggest you acquire two of each size, an adjustable is not always a satisfactory second wrench. I have metric combination wrenches with a 6- and 12-point option in many of the sizes, same as my SAE wrenches. Acquire metric sockets as well. With sockets you only need to buy the sockets themselves, so the ratchets, breaker bars, extensions really are not an issue you mentioned earlier, use the ones you have with the metric sockets.

 

[Hobo,NC]

Yes I do like the old Cats the Family has 2 of them a D-4 Grandpa bought New in the 30's and a NO6 Traxcavator .Basically a tracked loader with a 2yard heaped 1.5 yard struck. I have used both of them to moldboard plow with. Some days I think I would be better off going back to them. Less compaction and cheaper on fuel. Would need to load them all the time to work ground at my brothers places and mine across the road from dad's. Yes I was wondering if there were some sizes not used enough to justify buying. I guess it is not so such that I might just as well acquire all of them up to the 30mm. Thanks and the metric is pretty much a new world for me in wrenches. OR more like wenches. Such a pin with having to practically retool at my age rather than just use one set of tools. Nothing runs like the sound of an old Cat just purring along in the field.

8mm (5/16)
11MM (7/16)
16mm (5/8)
17MM (11/16)
19MM (3/4)
21 (13/16) 13/16 is a tight fit
22 (7/8)

 

[DaveBN]

They do make metric Allen wrenches also. I have two sets and have used many of them. They are relatively inexpensive and you can't cheat with Allen type heads, you need the exact correct one.
Dave

 

[moresmoke]

There are 2 different standards for metric bolts.

DIN (Aisan):


Read the outside columns

And ISO (German):

My experience has been that ISO bolt heads are the same size, DIN not always.

Above 30 mm, you can usually find an inch size that is close enough to work.

 

[caterpillar guy]

I have a small set of Allen wrenches in both SAE and metric with a whole tool box of SAE right now. I think the metric in allen wrenches is good for now. I was talking about the combination wrenches or open end wrenches . I have a fair accomplishment of Metric sockets for both 3/8 and 1/2 inch drive.

 

[Russ from MN]

There are 2 different standards for metric bolts.

DIN (Aisan):

View attachment 97531
Read the outside columns

And ISO (German):

View attachment 97532
My experience has been that ISO bolt heads are the same size, DIN not always.

Above 30 mm, you can usually find an inch size that is close enough to work.

There are 2 different standards for metric bolts.

DIN (Aisan):

View attachment 97531
Read the outside columns

And ISO (German):

View attachment 97532
My experience has been that ISO bolt heads are the same size, DIN not always.

Above 30 mm, you can usually find an inch size that is close enough to work.

I mainly worked on German equipment when I was a millwright, and the first chart is what they used, but we once had a Ford Thunderbird turbo coupe, and to work on that I needed a 15 mm, and I think I have run into it on my Triumph motorcycle also. And I had to buy an 18 mm deep well to change the sparkplugs, and it seem like a 17 is used somewhere.

 

[stdsch40]

I mainly worked on German equipment when I was a millwright, and the first chart is what they used, but we once had a Ford Thunderbird turbo coupe, and to work on that I needed a 15 mm, and I think I have run into it on my Triumph motorcycle also. And I had to buy an 18 mm deep well to change the sparkplugs, and it seem like a 17 is used somewhere.

I use the 17mm a lot on both the Kawasaki and the Chevy Cobalt. For some odd ball reason the Chevy uses 15mm in a few spots. Never once had the need for 18mm. But 19mm is very common. Don't confuse metric allen keys with imperial, you are asking for major trouble!

 

[bc]

Don't laugh. Crescent made adjustable wrenches when I was growing up and we just referred to them as Crescent Wrenches. Fast forward, HF adjustable has some with metric dimensions on one side and ASME on the other.

Rest assured you will never here me asking someone to hand me the Harbor Freight wrench!!

 

[bc]

I have a metric adjustable wrench I bought when working in Japan.

They might have called it a spanner. About every country in the world that were settled or contacted by England early on were ruined by the King's English. Worked all over the Middle East. When I yelled for a wrench, they would bring me a spanner.

The Shibaura engine in my Ford tractor uses metric and also a British pipe thread for oil lines in the block.

 

[wore out]

I use the 17mm a lot on both the Kawasaki and the Chevy Cobalt. For some odd ball reason the Chevy uses 15mm in a few spots. Never once had the need for 18mm. But 19mm is very common. Don't confuse metric allen keys with imperial, you are asking for major trouble!

19mm is so close to 3/4" they interchange.

LOTS of GM suspension and disc break fasteners ore 18mm.

 

[BarnyardEngineering]

Mostly suggestions on the sizes not use much or close to at all. I have some wrenches already and was going to fill out the set of what is left. Just thought maybe some sizes were not use much and might not even bother with them at least at this time. And how big do I stop at. I have SAE up to about 2-1/4 or a bit larger. Mostly working on the combine with these and maybe some future car or pickup use. I know a cresent/adjustable wrench will fit most all of them up to the size of the wrench and I see the humor being injected with this also as I grin with it. As for brands Im going to fill out a set of Blackhawk I already have and so far have quite a few of them along with some sockets in 3/8 and 1/2 drive. Not looking for 3/4 drive at this time. though I may have to buy a select socket or so over time in that drive . As for brand I hate to buy piece meal and I don't like buying cheap brand tools. I have found you get what you pay for in the long run. Like most of the cheaper brand ratchets they don't even service just swap it out with the old one for a warranty. Even Deere is doing that. My old Proto,Snapon,Mac, and S/K tools have been good over the years along with my 30-40 year old Craftsman tools. Ratchets were junk back then but the sockets have been pretty good.

Hmm, can't say I've had much call for metric any larger than 24mm, and most of the time I'm using it in place of a 15/16". Once you get up into those sizes you can usually find an inch wrench that fits close enough, or use an adjustable. Of course I'm not wrenching for a living so the infrequent use of an adjustable is acceptable.

Dad got a set that went up to 18 for Christmas one year, and figured he'd need larger metric wrenches because the USA was going metric (it was the 80's), so went out and bought 20, 22, 24, 28, 30, 32, and 35. I think I've used them more in the last week than Dad ever used them in the 35 years he owned them. I was using the 22 and 24 on SAE hydraulic fittings because it was cold and the 7/8 and 15/16 were in another building.

 

[BarnyardEngineering]

8mm (5/16)
11MM (7/16)
16mm (5/8)
17MM (11/16)
19MM (3/4)
21 (13/16) 13/16 is a tight fit
22 (7/8)

Don't forget 24 (15/16).

This all works because wrenches and fasteners aren't manufactured with such tight tolerances.

These guys that think your $3.69 a pound grade 2 hardware is manufactured to the .001" need to get a grip on reality.

 

[Brown David]

I'm gonna be in the minority here on this I think, but in my opinion adjustable wrenches are only useful when there is nothing else available or for bending/straightening stuff.

I can't recall the last time I used one for turning or holding a nut or bolt.

I have several collecting dust.

 

[tom upton]

Maybe its a canadian thing or maybe a tool nut thing but I have a whole tool box devoted to metric up to 30 mm. Working on just about any vehicle these days requires a pretty good set of metric tools. Even a couple antique tractors I have use metric fasteners.

 

[Dusty MI]

Do all 10 in. adjustable end wrenches open to the same amount?

 

[jaoneill]

8 mm can usually be subbed by a 5/16 16mm by 5/8 19mm by 3/4 only a few thousandths difference. My question is why does almost every set I see lack the 18mm? I have bought several different ones over the years and only one had the 18 but every one has the 19mm

I used to collect classic Mercedes diesel cars and drove a newer gasser so I also had to collect metric (what I refer to as commie) tools. Over the 30 or so years that I was working at that hobby I never remember ever using an 18mm. Now, with a Chevy and a Ford in the driveway it seems that I need an 18 all the time. The German's appear to also have a love affair with allen wrenches; I ended up with several different sets, the largest being a 1/2" drive allen set that I believe goes up to 17mm.