Sk 8mm hex

[nieuport17]

I just bought a couple sk hex sockets.
One of them was SK 8mm hex

SK Hand Tool 41407 3/8-Inch Drive Hex Bit
https://www.amazon.com/dp/B000X1PB8M/?tag=atomicindus08-20

Just for fun I decided to measure it with a caliper and compare with my existing Husky set.

Here are the numbers:
Husky 8mm - measured 7.985mm
Husky 5/16 - measured 7.932 mm
SK 8mm - measured 7.912 mm

I can’t believe Sk 8mm is smaller than Husky 5/16 !
I’m sure it will do the job fine, but a little disappointed that it’s not as close to 8mm
Or am I just reading this too much.

SK is US made.

 

[Toold_up]

How well can you use a caliper?


Husky 8mm
7.985mm = .3143 "

SK 8mm
7.912mm = .3114 "

Husky 5/16
7.932mm = .3122 "


5/16 = .3125
8mm = 0.3149


The difference is about the sheet of paper.

 

[Spacey_G]

If the measurements are to be trusted, the SK doesn't meet ISO 2936, which calls for 7.94 - 8.00mm width across flats.

Edit: Also, there's no point in reporting a measurement in millimeters out to three decimal places. That's precision out to 40 millionths of an inch. Your calipers are nowhere near that.

 

[Professional Tool User]

You are wasting your time by measuring it. You are better off with grabbing an 8mm screw , sticking the bits in, and feeling for difference in play. That will give you a better idea if the bit is way out of tolerance or not. The main gripe I have about USA made tools is that often they don't follow international standards. A Snap on screwdriver will strip a JIS screw but a Wera screwdriver will be able to do the job because it meets the ISO 8763-1 standard.

But then again, tolerances aren't everything when it comes to bit sockets. Strength is just as important. The true test of how good a bit socket is how much abuse it can take.

 

[Sloper0204]

Just for fun I decided to measure it with a caliper

If you are seriously being this nitpicky about it, why didn't you use the correct tool for the job? Measure it with a micrometer and get back with us, and provide photos please. At least that way a lot of the human error in how calipers are normally used will be eliminated.

 

[thin_concrete]

OP said he was taking the measurements just for fun, so let him have his fun. I don’t think he positioned this as an end-all measurement.

 

[nieuport17]

I didn’t realize you guys were going to make me work for this.
I do have a micrometer in inches.

Its 0.311”
Then go I to google and covert to 7.8994 (say 7.9 mm)

I think the message Im getting from you all is Im over think this.
Its a fine tool, Im still going to use SK over my Husky.

 

[tym]

So how does the Harbor Freight measure up?

 

[nieuport17]

So how does the Harbor Freight measure up?

Lol. There’s always that one person mentioning HF.
I don’t have a HF hex socket

 

[barrybeefburger]

Im still going to use SK over my Husky.

Why are you using an inferior tool?

 

[nieuport17]

Im still going to use SK over my Husky.

Why are you using an inferior tool?

?
I don’t think SK is inferior.
What hex socket(s) do you suggest?

 

[MattT]

I do have a micrometer in inches.

Its 0.311”

Either I've forgotten how to read a mic or that's 0.310x", with x being 2 or 3 tenths by the looks of it. So that bit is pretty badly undersized IMO.

 

[Toold_up]

I think the message Im getting from you all is Im over think this.
Its a fine tool, Im still going to use SK over my Husky.

Also, i've heard manufacturers undersize their tools because of the tolerances of the FASTENERS is all over the place. Hard to use a 8.00 mm hex when the fastener is 7.28 mm. Makes the tool manufactures look bad when their brand new tool "can't even fit this screw head".

Catch 22 if you ask me.

 

[RKA]

Yeah, that's pretty much it. There is always going to be some variance in the fasteners.
Further, if you're working a car, there will likely be corrosion and other **** on the fastener as well. The size difference here isn't what I would call substantial. As someone else said, use it and decide based on how it feels. Having two sets that are slightly different wouldn't be a bad thing, but 99% of the time the SK should work out fine.

Last year I was changing out the half shaft on my car. It needed a 17mm bit, I cleaned out the rust and tried to put a new gearwrench bit in it...didn't fit. Wasn't going to fit unless I used "persuasion". Luckily, I found an old 17mm bit a friend gifted me many years ago...completely forgot I had it. And wouldn't you know it...it fit perfectly.

 

[Steve_P]

Ok, so a bit that's 1.5% under the nominal size is somehow a huge issue. Because there's no way the internal hex on the screw could ever be .004" under nominal. Nope, that'd never happen on a mass produced 50 cent screw.