Why do Metric socket sets skip some sizes?

[rogersmithiii]

Like 20 mm, 23 mm, 4.5 and 5.5?

My Craftsman sets that I bought skipped these sizes.

Any idea why?

 

[redragoon]

Sometimes it is because those are uncommonly used or have an SAE equivalent. Mostly it is to save money.

 

[vjquan]

Unless you have OCD in filling a socket tray, you'll very likely never see those sizes in fasteners. 9 and 11 also come to mind.

 

[dmdc411]

Craftsman is great for only giving the popularly used sizes. I worked in aviation for many years. We pretty regularly used 11/32 inch wrench and socket. Outside of aviation, almost never! So I bought those less common sizes individually. They always had them on hand.

Sent from my SM-G970U using Tapatalk

 

[M6erfan]

Sometimes because regional.

Look at Euro made sets vs. Japan made sets (DIN vs. JIS) for example.

 

[Dave455]

There are several different standards in use - ISO (International), DIN (German), JIS (Japanese) and ANSI (American). They all use their own range of nut / bolt head sizes, with a good degree of overlap (I think they all use a 10mm bolt head on a 6mm bolt) but... there are some sizes that are never used, 20mm being one of them, so most manufacturers don’t include these in a set.

There are some sizes that don’t feature in any of the current standards, but may turn up in some of the older ones. 23mm for example, is a standard size in the old French system, so you might find it in some sets, but not the majority.

 

[rogersmithiii]

Thanks! This backhoe project has been the most amazing educational experience so far.

 

[wolf_from_wv]

Seems like 23mm was used when changing 2.2L timing chain.

Isn't 20mm used for some lug nuts?

5.5mm was used for GM trim/dash screws.

 

[anavrinIV]

16mm is often skipped...I found this out when I worked at a place that regularly used bolts with 16mm heads. I also have a use for 23mm and 9mm tools on my car (mfg in Japan).

But the answers above are correct, they are uncommon sizes and thus skipped to keep set costs cheaper. My Tekton sets are no-skip and came with all of the sizes mentioned here in my sockets and a lot of them in wrenches as well

 

[engineer2]

16mm is probably skipped (Tekton) because it is close to 5/8", but if I were working on VW/Audi, I would still want a 16mm.

 

[four.cycle]

Early on, tool manufacturers only provided the most commonly used sizes. As time went on, some manufacturers included all sizes in sets.
That varies from brand to brand, and when the set was made.

The only thing I have which could be considered "current production" is a little "Tekton" set I picked up a couple months ago that includes all sizes (including the 4.5 and 5.5 mm)

But there have been other makers who included all sizes - I have a set of "Granco" 1/2" drive sockets which runs from 10-32mm, and a set of Indestro 1/2" drive sockets that runs from 10-22mm, as well as Thorsen and S-K sets that include every size.

 

[Ralf11]

I wish more sizes were skipped. I want a fatwah to change all JIS into DIN too.

 

[LXCam]

Seems like 23mm was used when changing 2.2L timing chain.

Isn't 20mm used for some lug nuts?.

The one and only time I've ever whipped out the 20mm stuff was building the new model Pacifica van for a Chrysler event in 16. They used that size on the rear camber adjustment bolt.

Had it not been for OCD and those unfilled pegs on the Hansen racks....I'd have failed at my project.

 

[javyLSU]

Anyone not needing a 16mm has probably never had to change a serpentine belt or a pulley on a Jeep/Dodge/Chrysler product...

 

[alfazer]

In Europe, 11mm is pretty common a M6 bolt. Both on hardware and European cars.
9mm is the one that I never seem to have a use for.

 

[GrantCee]

Unless you have OCD in filling a socket tray, you'll very likely never see those sizes in fasteners. 9 and 11 also come to mind.

Depends entirely on what you're working on and what you're doing. If all you do is change the oil on a Toyota, then you probably won't need them. But if you do involved repairs on multiple vehicles (or have had a mix of US, Japanese, and European marques over time) then you probably will. Throw some farm equipment into that and it's almost guaranteed that you'll need everything.

(Our old Suzuki Samurai and Sidekick, for example, had tons of 9mm fasteners. I've also used 11mm a fair amount, and 20mm and 23mm have seen action more than once.)

 

[GrantCee]

In Europe, 11mm is pretty common a M6 bolt. Both on hardware and European cars.

That explains the 11mm fasteners on our Saab.

 

[Dave455]

Generally, 6mm bolts have a 10mm hex. ISO and DIN both use 10mm.

7mm bolts, which are a ‘non preferred’ size, use an 11mm hex, but they are pretty rare.

There is an old Swedish standard (SMS 1412) which specifies an 11mm hex for a “large” 6mm bolt, but that’s the only one I can think of. That would have been the one on the Saab!

 

[Iowafox]

This is one reason I got away from Crapsman almost entirely now yes I know alot of companies do skip sizes but I work on everything from Ford, GM, Chrysler, Honda to farm equipment and I have learned to appreciate socket sets with no skips. Maybe this is one reason I love my Pittsburgh Pro 225 piece mechanics tool kit. Every socket no skips and all 6pt. I like knowing I have the sizes needed and will need in the future. That and there just a damn good socket never had one break after all the abuse and fitment is spot on.

 

[dcummer]

Unless you have OCD in filling a socket tray, you'll very likely never see those sizes in fasteners. 9 and 11 also come to mind.

Used both last weekend replacing a brake line on a 2001 Mercedes e320. Tube nut is 11mm and the bleeder is 9mm.

Oops - I replied too fast, you are commenting on sockets, and my example was wrenches. Sorry!

 

[macgee]

As others above have correctly stated, tool manufacturers skip non standard esoteric sizes that do not fit regulated size fasteners or standards, again as stated above. There's a very good reason why they're skipped as 99% user's not needing them and for economic reason but drives OCD buyers crazy.

However, there will always be some mechanic speaking up who works on a particular model car/truck/train/unicycle with one particular part on that model that will speak up saying I totally use that size every day. The odds of the avg. tool guy ever going to need it is pretty much nil and whoever does, can easily order one separately to their hearts content. Like a 9mm hex wrench, there no need for them unless you work on some random part on some random car. Just order one if you need it but it does not fit any standard made fasteners in EU, Jap or USA.

It's like buying a very nice set of threading taps and dies, you're not going to find a #4-32 or a #12-32 or #1-80 in the set. They're either esoteric or specialized sizes that 99.8% of tool buying population will never use and those are actually documented sizes. I use them but I would never expect to see them in a set, if they were, then that would be some crazy uber expensive set of taps that very few would ever buy hence the rational step by sellers to skip them. Ok, rant over

 

[BiggityBen]

Generally, 6mm bolts have a 10mm hex. ISO and DIN both use 10mm.

7mm bolts, which are a ‘non preferred’ size, use an 11mm hex, but they are pretty rare.

There is an old Swedish standard (SMS 1412) which specifies an 11mm hex for a “large” 6mm bolt, but that’s the only one I can think of. That would have been the one on the Saab!

that's interesting. i had to replace a block heater on an SDMO 500kw generator (Volvo powered) and it's held into its bracket with 11mm bolts. only time i've ever used one. might make sense if that's still modern Swedish though SDMO themselves are French

 

[Jtels85]

11mm is common on EZ-GO TXT’s to remove the roof and rear seat back. I’ve used 20mm on really corroded 19mm’s.

 

[rogersmithiii]

What I hate is when a piece of equipment mixes metric and standard. It's almost as if I have to check four to six sockets to find the best fit. My new Deere backhoe is the worst. Metric, standard, and fifty million bolt and nut sizes, sometimes on the same item.

 

[rogersmithiii]

I was at Ace Hardware, and my local independent, and picked up Craftsman and Channel lock sockets to start filling in the gaps. Needing a size on Sunday at 3 PM kind of ruins your whole day.

 

[king nero]

9 mm is the nut size for the electrical connection of (I think up to around 3 kW) 3 phase electric motors.
I even have (fixed, not 1/4" drive) deep socket nut drivers in 9 mm...

Can't remember ever using an 11 mm wrench or socket, but 16, 18, 20 and 22 mm are becoming more and more popular due to the change of the EN/ISO standard that defines the head size of metric bolts few years ago.

As someone said before, that's where your OCD really gives you the edge...

 

[CoogarXR]

I never tried to buy a full set of anything with no skips. Mainly because most of my sockets and wrenches were purchased before the internet, and I didn't really know I had holes in my lineup, lol.

Now, with this site, and the help of my crippling OCD, I have full runs of everything. I just filled out the sets I had by buying individuals as I found them. I did have to mix brands for some oddball sizes. I found that less offensive than leaving a gap.

 

[GrantCee]

What I hate is when a piece of equipment mixes metric and standard. It's almost as if I have to check four to six sockets to find the best fit. My new Deere backhoe is the worst. Metric, standard, and fifty million bolt and nut sizes, sometimes on the same item.

My New Holland is the same way: the tractor itself is metric, the FEL is all SAE.

I have friends in the heavy equipment repair business; their Miller welders have metric engines, but everything else on them is in inches.

 

[BikeRider]

I think that one of the jam nuts or wrench flats on the outer tie rods of one of our cars is 20mm, so I got a combo 20/22mm open wrench for tightening or adjustment, although I can just as well use a locking adjustable or pipe wrench for that, and often have. Unless both the nut and flats are 20mm, in which case I needed both. But I've never come across 20mm otherwise on the 3 cars I work on regularly, 2 sedans and one a sporty coupe.

 

[Orangina]

In some small set a lot of uncommon sizes might missing,
but professional tool sets include more or these could be extended.
Socket examples:

sockets 1/4" 3 - 14 mm - including your 4.5 and 5.5
sockets 1/2" - 8 to 36 mm (only missing 31, 33, 35) - inluding your 20 and 23
sockets 3/4" - 19 to 60 mm (some more uncommon sizes missing)

 

[f121]

Unless you have OCD in filling a socket tray, you'll very likely never see those sizes in fasteners. 9 and 11 also come to mind.

11mm is commonly used for m6 fine thread nuts on European vehicles.

23mm is fairly common too, I've definitely used one recently, I think on a m16 nyloc.


As far as I can remember, the only time I've used a 20mm is when I couldn't find my 19mm

 

[NoahG]

So many sets skip the 5.5, and I wish they wouldn't, as I seem to need one a couple times a year. Good thing 7/32" works and I have plenty of that from surplus sales.

 

[Rickster]

Knowing the compromises company bean counters force on engineers I’m willing to bet sizes are skipped to hit certain price points.

 

[Firebrick43]

Price point. They sell incomplete set to the average joe(cause he probably won't use them anyway) and sell them at a competitive price. If they included the other sockets they to would be 25 buck plus over other sellers of incomplete sets.

Craftsman did make complete sets. I have a 2000's socket set that is complete from 4 to 36 including the 4.5 and 5.5 mm.

On SAE side it even has 19/32, 21/32, and 25/32

 

[simnil]

That explains the 11mm fasteners on our Saab.

M6 flange nuts are sometimes 11mm.

Flange nuts and bolts are great for lots of things BUT why they decided that the bolt head should "always" be a size smaller than the nut I can't understand.

 

[f121]

M6 flange nuts are sometimes 11mm.

Flange nuts and bolts are great for lots of things BUT why they decided that the bolt head should "always" be a size smaller than the nut I can't understand.

M6 regular or fine? Back when I was a kid with one roll of spanners and one socket set, I was always really grateful when the nut was a size bigger than the bolt. Now I own more than one 10mm socket, it's less of an issue

 

[BrandoJames]

16mm is probably skipped (Tekton) because it is close to 5/8", but if I were working on VW/Audi, I would still want a16mm.

I had to pull the clutch on my John Deere riding mower (just to replace the drive belt!). Clutch bolt with a 16mm fastener. Fortunately I had a Mac socket set that included a 16mm. Removing that clutch was a gut-buster.

My Makita 12 volt 1/2" impact gun failed. Next up, my ancient corded 1/2" GM Performance impact = Fail. I had to go with a 1/2" Matco 88 hand ratchet and a pair of vice grips. Finally broke it loose.

That was three months ago, and my right shoulder still hurts. Someone pass the Ibuprofen.

 

[engineer2]

If you are on the Makita system, get the XWT08Z impact. 740 ft.lbs. of Fastening Torque and 1,180 ft.lbs. of Nut-Busting Torque.

 

[bwringer]

I've put more than one socket or wrench set back on the shelf or removed it from my online cart when I noticed 12mm and 14mm missing.

Skipping 20mm I could understand, but WTF would you skip these?

 

[BrandoJames]

I've put more than one socket or wrench set back on the shelf or removed it from my online cart when I noticed 12mm and 14mm missing.Skipping 20mm I could understand, but WTF would you skip these?

Toyotas need four sockets: 10, 12, 14, 17. Add 21 for lugnuts. Incredible that 12 & 14 would ever be skipped in a socket set.