Why do Metric socket sets skip some sizes?

[dchawk81]

All SAE sets skip. That stupid system can have 64 as denominator and it is just hard to spot the missing one, like 7/64 or 9/64. I have never seen a set start from 4/64 to 64/64.

I heard this is part of the citizenship exam. Spot the missing SAE.

 

[DAustin]

To get you back into the store… to buy the missing sizes, that you… all of a sudden, need so badly.

Back when Sears was still a thing, I would look around Sears while my wife shopped at the mall.

With some Craftsman sets they would miss a couple of sizes, and to buy the wrenches you needed it would cost about what the set cost you.

 

[Sal Bandini]

I know this is a slightly old thread but, why do cheap wrench sets skip 15mm?! I commonly travel with family bikes. 15mm is perhaps the most common fastener size on common bikes as it's the size of the wheel nuts and the pedals. So when I'm trying to break down a bike to better fit in the car taking the wheels and cranks off is a standard thing. I don't need much of a wrench but I don't want to loose one from my box. I was hoping one of the inexpensive Walmart sets would work. $6 for a few combo wrenches, who cares if you loose them. I've bought two such sets for road side emergencies. Sorry, no 15mm.

I guess it's fitting that I ended up spending $15 to get a set that included that 15mm wrench. Perhaps that's the hook. Still, 15mm doesn't have an obvious SAE equivalent so why skip it?

In the rare case that I do encounter a bike without QR I just use my pliers wrench. Seriously, just carry an adjustable wrench or spend $4.50 at Menards for 15mm combo. Me, I prefer the Knipex because it's way cooler.

Edit: and by removing cranks, I hope you meant removing pedals, else you will need more than a 15mm wrench.

 

[sdowney717]

https://www.autozone.com/ratchets-sockets-and-wrenches/impact-socket-set/p/duralast-1-2in-drive-metric-impact-socket-set/914179_0_0

An impact set that skips 14mm, now how dumb is this. I own it. Comes in a nice plastic case.
Why skip 14mm?? Common size bolt head. When I bought it I just assumed it would have a 14mm.

The Duralast impact socket set is made with chrome molybdenum that provides the best performance for the toughest jobs.

• 
  
  Contains: (10) 1/2" Drive Metric Impact Sockets: 11, 12, 13, 15, 16, 17, 19, 21, 22, 24mm
• 
  
  Forged Chrome Molybdenum Alloy Steel for strength and durability in impact use
• 
  
  Chamfered lead-ins help to provide fast and easy placement of sockets and accessories onto drive
• 
  
  Meets or exceeds ASME standards

 

[Wrench97]

https://www.autozone.com/ratchets-sockets-and-wrenches/impact-socket-set/p/duralast-1-2in-drive-metric-impact-socket-set/914179_0_0

An impact set that skips 14mm, now how dumb is this. I own it. Comes in a nice plastic case.
Why skip 14mm?? Common size bolt head. When I bought it I just assumed it would have a 14mm.

The Duralast impact socket set is made with chrome molybdenum that provides the best performance for the toughest jobs.

• 
  
  Contains: (10) 1/2" Drive Metric Impact Sockets: 11, 12, 13, 15, 16, 17, 19, 21, 22, 24mm
• 
  
  Forged Chrome Molybdenum Alloy Steel for strength and durability in impact use
• 
  
  Chamfered lead-ins help to provide fast and easy placement of sockets and accessories onto drive
• 
  
  Meets or exceeds ASME standards

That's also missing the 18mm and a 10mm comes in handy.

 

[Ton ton]

That's also missing the 18mm and a 10mm comes in handy.

10 mm disappears soon after you start using the set. LOL!