Why do they skip sizes of metric combo wrenches?

Nov 05, 2010 Last reply: 6 years ago 119 Replies

There are at leat 3 metric "standards" and each uses a few different sized bolts, and different head sizes You have the German DIN system, the Japanese SI and the American ANSI/ASME

The SI is actually common pretty much world wide except America and Germany - there are exceptions.

Depending on the market you may get 10mm and not 11, you may or may not get either 12 or 13mm, and 17 or 18mm - and some get 15, others do not.

I've worked on vehicles using every one of them (not all on the same vehicle) - I'd have been totally lost without a minimum of 8, 10, 12,

13, 14, 15, 17, 18. 19, and 21 mm On Toyotas the 11 and 13 and 18 were not required - on American iron the 10 and 12 are pretty much redundant - along with the 17, I believe.

If a nut is so rusty you can't get the correct wrench to fit, it's probably time to take other measures. Wire brush the rust, apply penetrating oil, maybe apply heat, use vice grips, etc.

On Volkswagens, the most used wrench sizes are 10mm, 13mm, 15mm, 17mm, and

19mm.

However, brake bleeders require a 7mm, 8mm, 9mm, or 10mm wrench, depending on the brand and location of the bleeder.

I also need an 11mm wrench to remove my carburetor cover.

I think the front strut nuts need a 22mm wrench.

12mm, 14mm, and 18mm are probably the sizes I use the least, but occasionally I'll run across a fastener than needs those too.

Anthony Watson

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You never mentioned the 16mm. My set lacked that one, and I have needed that one numerous times. I found a few others that were missing. One day I just bought all the individual wrench sizes that my set lacked, and made a complete set. I did that for my box wrenches, sockets and nut drivers. I dont think I've ever found a complete metric set in the stores.

What does "the 10 and 12 are pretty much redundant" mean?

How does "redundant" apply in that context?

I've found the 10 popping up in the strangest places. Even Harley throws a couple in to keep you guessing. I've got some of the less popular large sizes for axle nuts on the bikes.

Oops, yep, I guess I forgot the 16mm. I don't have a wrench that size, and apparently have never encountered a nut or bolt that needed it.

I have a full set ranging from 7mm through 15mm. Then I have 17mm, 19mm, and 22mm. That seeems to cover everything I work on.

I also inherited a small collection of imperial wrench sizes from my step dad (maybe 5-7 wrenches total). I don't use those much, but every now and then they come in handy.

My 6-sided sockets are more complete, running from 4mm all the way up to

30mm for my axle nut.

I bought wrenches and sockets over time as I needed them. So the collection I have seems to accomodate everything I'm working on, and I didn't spend money on sizes I never use.

Anthony Watson

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The stores all carry Asian junk. Even NAPA. Online is a different matter:

****OR****

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My first metric socket set was an S-K set (45+ yrs ago). I don't recall any missing sizes.

nb

But do you recall there NOT being any missing sizes? Where were you on the night of June 17, 1965?

I'm guessing he means "common".

I've often been able to use one of the standard sizes in place of the less common metric sizes such as 18mm. Otherwise, an adjustable wrench has saved me, though, in some tight spots, it's not always the answer. Overall, I nice ratchet/socket set with all sizes usually suffices.

I was guessing they are a close match to SAE sizes, although that took some guesswork. At first I thought he was saying 10 and 12 were about the same thing and could be used interchangeably, which makes no sense.

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Never used. - or very VERY seldom used.

Harley uses some Japanese (or other Pacific Rim) sourced parts that WILL have 10mm heads on 6mm bolts.

WHAT? The all American made motorcycle? I'm shocked!

Except for the forks, carb, battery, probably the tires, the horn, and a few other minor pieces... Most of the bling in the boutique is from China.

That's funny, my first metric socket set was S-K brand too. They were the first tools I bought when I started driving. I think I may still have one or two of those sockets left. They were fairly good quality compared to the cheap bargain store sockets my step-dad always bought.

Most of my hand tools now are Craftsman's that I've had for 30 years or more.

Anthony Watson

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Yep, same here. I have an imperial socket that fits the nut on my VW steering wheel. I'm sure it must be a metric size, but I inherited the imperial socket from my step-dad and it works fine. So I've never bothered tracking down the metric socket.

Sometimes a nut will be deformed just slightly so that the actual metric socket doesn't fit, but an imperial size will. Six point sockets are much better for this sort of thing than 12 point sockets.

Anthony Watson

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It goes both ways... Several months ago I needed to replace a bolt for the seatbelt in my 1976 Rabbit. It's a German car, so I figured it was a metric bolt. I tried every available metric thread pitch, but nothing fit right. On a whim I tried a fine thread imperial bolt and it threaded in perfectly!

Anthony Watson

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BSF? I didn't think that stuff fit anything. In youthful ignorance I got involved with British cars and remember the joys of Whitworth.

If yer Craftsman tools are really 30 yrs old, they are probably better than what Sears is offering, today. Most Craftsman tools --not all-- are currently made in China. This unlike S-K Tools, which are still made in the USA. ;)

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nb

Yep, I bought most of my hand tools in my late teens and early 20's after I first started driving. I'll turn 53 in a few months. :)

I occasionally still buy a Craftsman wrench or screwdriver if I'm missing a size or something, but that's fairly rare. I haven't noticed any major difference in quality though, compared to my older hand tools.

I haven't seen S-K tools in my area for a long time. I didn't know they were still being made.

Actually, I bought a few "Husky" brand hand tools at Home Depot to keep in the car recently. I'm sure they're made in China (everything is) but they seemed to be decent quality.

I remember the cheap sockets my step-dad used to buy. The chrome was peeling off, and they would either strip out inside or just crack in half when you put any pressure on them. I quickly learned to buy my own tools and not borrow his. :)

Anthony Watson

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