impact sockets with both metric and sae sizing

[moron88]

yesterday i picked one of these up at a pretty good price (good enough, anyway) http://tekton.com/Sockets_and_Ratch...Impact-Socket-Set-3-8-1-1-4-in-8-32-mm-6-pt_2. something that intrigued me was the few sockets that have both measurements. as best as i can tell, the first measurement is the actual and the second is the "close enough" size (dont have calipers at the moment). what do you guys think? sketchy or practical? both?

 

[gdocktor3]

They are only off by thousands of an inch, so it definitely "close enough"

5/8 is .625", 16mm is .630"
5/16 is .313", 8mm is .315"
7/16 is .438", 11mm is .433"
3/4 is .750, 19mm is .748"

 

[G-Ram]

Some of my snap on 3/4" drive sockets are marked with both sizes, never seen that in the smaller drive sizes though..


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[moron88]

They are only off by thousands of an inch, so it definitely "close enough"

5/8 is .625", 16mm is .630"
5/16 is .313", 8mm is .315"
7/16 is .438", 11mm is .433"
3/4 is .750, 19mm is .748"

yeah, i did some of the math myself after posting. i'd hazard a guess that there's that much tolerance in head size on some lesser quality hardware. now just need something to test their overall quality and durability on.

 

[davewo]

I've never seen dual-marked sockets before, but pretty much all 6-point sockets contact the nut/bolt at a point within the flat of the nut/bolt and don't rely on a tight-fitting hex geometry.

 

[bwringer]

Yup, perfectly legit way to save a buck or three and some space and wieght.

But there are some skipped sizes in that set that don't make much sense. I'd be pretty cheesed about not getting a 24mm-15/16" deep, a 21mm deep, a 22mm shallow, and no 3/8" drive 10mm shallow. Also, if there are no 13, 14, 15, 16mm-5/8", 17, or 18mm deeps, why did they include 1/2", 9/16", and 11/16"?

 

[moron88]

Yup, perfectly legit way to save a buck or three and some space and wieght.

But there are some skipped sizes in that set that don't make much sense. I'd be pretty cheesed about not getting a 24mm-15/16" deep, a 21mm deep, a 22mm shallow, and no 3/8" drive 10mm shallow. Also, if there are no 13, 14, 15, 16mm-5/8", 17, or 18mm deeps, why did they include 1/2", 9/16", and 11/16"?

looking at it more i have to agree, the size choices are a bit weird. i got it for $45 at a local store that buys wholesale and leftover/excess inventory. pretty sure they're just a straight up tekton dealer though (also carry another brand called 'grip'. made in Taiwan but their socket sets seem decent for the money, just a bit more than i'd care to pay ($28 for a 22 piece 1/4" metric or sae set with ratchet and extension, $40 for a similar 1/2" drive set. prices usually negotiable)).

 

[American Locomotive]

Yup, perfectly legit way to save a buck or three and some space and wieght.

But there are some skipped sizes in that set that don't make much sense. I'd be pretty cheesed about not getting a 24mm-15/16" deep, a 21mm deep, a 22mm shallow, and no 3/8" drive 10mm shallow. Also, if there are no 13, 14, 15, 16mm-5/8", 17, or 18mm deeps, why did they include 1/2", 9/16", and 11/16"?

To be fair, a 1/2" socket almost always works on a 13mm bolt (and 13mm sockets usually work on 1/2" bolts, not always though), and 9/16 sockets almost always work on 14mm bolts.

 

[Gmonkee]

Take a full metric set and add the following:
1/4"
3/8"
9/16" because neither 14 nor 15 mm are exactly right

That will get you up to 19 mm or 3/4" with minimal carry weight and still full capacity in both wrench and sockets.

I have been working like this for years. The last few years I kicked it up to 7/8 or 22 mm. I don't move the kit as far anymore.