Various brand wrenches measured micrometer

[boybacon]

LTLFTP (Long Time Lurker, First Time Posting). I was bored the the other night, so I sat down with some open end wrenches, a pen and a digital micrometer. Everything is measured in MM, and all were measured at approximately the same spot on the wrench opening.

14mm marked size
Gear Wrench - 14.3mm
Craftsman - 14.25mm
Wrench Force by Snap On (long story on those wrenches) - 14.15mm
SK - 14.13mm

10mm marked size
Gear Wrench - 10.25mm
Craftsman - 10.14mm
Wrench Force by Snap On - 10.11mm
SK 10.07mm

5/16 marked size Ignition Wrench
Craftsman - 8.04mm
Snap On (standard off the truck) - 8.00mm

9/32 marked size Ignition Wrench
Craftsman - 7.17mm
Snap On (standard off the truck) - 7.04mm

Measured (but did not record) a few more, and my notes show that Gear Wrench were consistently oversized by the same .25mm across the board (on the set of Metric combo wrenches i measured), and Craftsman were a little more varied on the oversizing, but were always tighter in tolerance than the gear wrench. The SK wrenches were consistent, and tighter than both Gear Wrench and Craftsman. I wish that I had more off the truck Snap On wrenches to measure!

Anyway, that's what I found, FWIW

 

[Case]

in before the gw bashing...

 

[boybacon]

Didn't mean to bash anyone. Just made some observations on tools from my tool box.

 

[DavidB]

Cool info. Which Craftsman were those, Pros or Raised Panel? For others as good with the metric system as I: 5/16"=7.9375mm 9/32"=7.14375mm

 

[boybacon]

These were PRO for the 10mm and standard raised for the 14mm.

 

[Stephenw]

What did you use to take the measurements? Are you sure you were exactly perpendicular to working surfaces of the wrenches?

 

[tonydanzah]

where did your nose go stephenW?

 

[Stephenw]

Craftsman raised panel vs Snap-on Flank Drive Plus.

 

[Stephenw]

where did your nose go stephenW?

The avatar program I used doesn't include noses.
http://www.weeworld.com/

 

[Stuart in MN]

This brings up the question: what's the optimal size? Obviously a wrench needs to be just a little bit larger than the nut, and to a point the larger it is the easier it will be to fit over the nut, but if it's too big it will tend to round the nut off.

 

[tonydanzah]

oh and whats the story with about the wrench force?

 

[boybacon]

I used a Park Tool digital micrometer, zeroed after every measurement. Not the top of the line micrometer, but for my purposes it worked fine. I cannot say if the measurement was taken parallel every time or not, as I'm not a tool maker, or measurer by trade.

Wrench Force is a brand owned by Trek Bicycle Corp. They contracted with Snap On a few years back to produce a line of tools in the US with the Wrench Force name. Wrenches, adjustable wrenches, sockets, screwdrivers and a few others. They were all made in the USA, so I assume they came from the Williams factory. They were not high polished, but more of a satin / rough finish with a nickel plate on them. The tools would rust if not cared for and worked great for fixing bicycles. Mostly metric tools, where applicable. Came with a limited lifetime warranty from the Wrench Force brand. Eventually the Wrench Force line moved to Taiwan / China and the Snap On association ended.

 

[MarcSeattle]

My Snap-on (current generation OEXM140B) measured perpendicular to the length of the wrench at halfway point of the open end: 14.12mm

Searching around, here's an interesting one: Proto/Mac/Blackhawk ratcheting stubbies: 14.07mm

 

[dan76]

Were these wrenches subject to long-term usage prior to your measurement?

 

[boybacon]

These wrenches are all nearly new.

 

[Monte]

If the measurements are rigth, Gearwrench is out of specs. The ISO 691 tolerances say the maximum size for a 14mm wrench is 14,24 mm. 10mm wrench max. size 10,15 mm.

 

[MarcSeattle]

Were these wrenches subject to long-term usage prior to your measurement?

On the wrenches the open ends don't see much use. I try to avoid using the open end of any wrench. After a few busted knuckles as a kid I never use an open end where it could spread and slip. If I catch your meaning, the dimension of what I measured would likely be the same as new.

 

[DavidB]

If the measurements are rigth, Gearwrench is out of specs. The ISO 691 tolerances say the maximum size for a 14mm wrench is 14,24 mm. 10mm wrench max. size 10,15 mm.

Are the tolerances determined by a percentage over the marked size or does it vary for different sizes? Same thing for sockets? I tried looking up ISO 691 myself but couldn't find it without having to pay.

Thanks,
David

 

[Bruce Lancaster]

A number from the past...Ford 1932 parts catalog. A combination wrench is listed for Ford cylinder head nuts, which are 11/16". Wrench is listed as 45/64". Truth in packaging?

 

[Monte]

Are the tolerances determined by a percentage over the marked size or does it vary for different sizes? Same thing for sockets? I tried looking up ISO 691 myself but couldn't find it without having to pay.

Thanks,
David

here the answer:

but i think i was wrong ....10.19 and 14.27 is right as the maximum ?

 

[alex71]

The tool you are using is a caliper, not a micrometer. Keep in mind, that even though it may give you readings down to .01mm on the display, the actual resolution is probably only .025mm (.001").

 

[boybacon]

Thanks. Yes, it's a caliper. Sorry about that. I actually thought about that at work today and kicked myself in the rear. I know the difference between a micrometer and a caliper. Doh! The Park version is a relatively inexpensive "made in china" tool. I suppose to be really accurate, I'd have to use a measuring device made specifically for the purpose, eh? I would love to measure these again after long term use. I have several older Craftsman wrenches that were "pre-owned" before I got them, and they have all sorts of dings and whatnots from being used (and abused, I'm sure) over the years. I had never used SK tools before, and picked up a 16 piece stubby combination wrench set off of craigslist (8 metric, 8 SAE), and I really like the feel of the "superkrome".

 

[alberto]

Interesting post, specially the readings and the ISO tolerances. I'll have to measure mine, see what I get.

 

[AustinRoepke]

There's a set of standardized tolerances in my room somewhere... Ah found it!

There's a set of tolerances for sliding fit systems (ie wrenches), in which these fall into.

ANSI preferred shaft sliding close running fit listing for some sizes:

First number will be ideal bolt size, the next will be the tolerances for bolt dimensions (hole), third will be wrench tolerance range (shaft)

size, (max, min), (max, min)
10mm, (10.000,9.985), (10.035, 10.013)

I think they follow ANSI tolerances for close running fits, butthey may use another fit (there's loose running, free running, close running, sliding, and locational clearance fits for hole-shaft tolerances.)

EDIT: They must follow the loose running standards. But, only then Snap-On and SK follow these standards.

I'm just going to go scan in the page from my book and put it up here in a sec.

 

[AustinRoepke]

Another note:

ANSI doesn't follow a linear scale of tolerances wrt the ideal bolt size. It 'jumps' in size of tolerance range as the dimensions get larger.

 

[ultimakf7]

very interesting. i guess part of the reason why snap-on tools and such are more expensive is due to the manufacturing tolerance.

 

[MarcSeattle]

I measured the Gearwrench flex wrenches that I got on the $35 sale from Napa Auto Parts. The 14mm measured 14.08. I measured perpendicular to the length of the wrench at halfway point of the open end. My old Craftsman raised panel 14mm measured 14.23mm and my Snap-on 14.12mm.

 

[alberto]

I just received a set of Wright combination wrenches, so these measurements are for a brand new, out of the box, never used set:

Nominal (mm) Measured Actual (mm)
7 ------------------- 7.12
10 ------------------10.15
11 ------------------11.11
12 ------------------12.19
13 ------------------13.15
14 ------------------14.14
16 ------------------16.15
18 ------------------18.20
21 ------------------21.21

Based on these numbers, the Wright wrenches meet the ISO standard. Don't know what the ANSI standard might be.

Alberto