How good are you at eyeballing hex fastener sizes?

[thool]

Still got some way to go, but with SAE, I am usually about 8/10 (7/16" almost always stumps me). Most everything I do work on is SAE, and I'll admit the smaller sizes like 1/4" are harder for me.

Metric is a different story, maybe 5/10 times I get those right.

How good are you at getting the right socket the first time?

 

[gdocktor3]

I seem to be good at 8 and 10 mm, 3/8, 1/2, 3/4 and 7/8. The rest are lucky guesses if I get them right.

 

[T45]

This is why the invented the digital caliper

 

[bobcatdan]

For a long time I was about 99.9% correct in guessing the correct size. Last few years been slipping a bit. Then again I seem to be running across a lot of 9, 11, 12,14 and 16 mm that were rare as hen's teeth before.

 

[T45]

I think it helps if the oem is on a consistent standard,

din, jis etc sequences are pretty natural and not that confusing

can get stumped by 11mm bleeders every once in a while tho, agh

edit: what bobcatdan said !

 

[2ndGearRubber]

Pretty damn close. Usually if I grab the wrong side, it's because I didn't actually look at the socket I grabbed, I just went for the general space it is in.

Cars usually have a pattern of sizes. Unfortunately, some car makers are changing to what I consider "unapproved" sizes.


I'm pretty good with torx, if I'm doing hex by feel (behind a caliper for the slide pins), I'm around 50%.

 

[ZRX61]

I've been known to get it right at 30ft across the hangar. I have pretty good sight for distance, can't see **** right in front of my face.

 

[abvw]

9/10, pretty easy once you group them to Euro, Japanese and American (automotive).

Fasteners are either SAE, DIN or ISO, they almost never overlap unless some baffoon used random fasteners.

 

[Jeeper]

About a 2 out of 10. I get a lot of exercising walking back to the toolbox.

 

[FigureItOut]

10/10 if it's a 7, 8 or 10. Anything else I'm pretty poor. Torx I'm pretty good at, I couldn't call out the number but I can grab the right bit most of the time.

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[Wes J]

I'd say 90%. Automotive uses so many custom fasteners and non-standard head sizes that it's hard to get them right.

If you work on industrial equipment or other machines that use standard fasteners, it's much easier. 1/2 bolt needs a 3/4 wrench, 5/8 bolt needs a 15/16, etc. Same with hex keys. 1/2 SHCS needs a 3/8 key, etc.

Torx is mostly an automotive thing. You rarely see them outside the auto world. Sometimes you see small ones on electrical components. I've never seen an outside torx anywhere but a car.

 

[SAATR]

I'd say 90%. Automotive uses so many custom fasteners and non-standard head sizes that it's hard to get them right.

If you work on industrial equipment or other machines that use standard fasteners, it's much easier. 1/2 bolt needs a 3/4 wrench, 5/8 bolt needs a 15/16, etc. Same with hex keys. 1/2 SHCS needs a 3/8 key, etc.

Torx is mostly an automotive thing. You rarely see them outside the auto world. Sometimes you see small ones on electrical components. I've never seen an outside torx anywhere but a car.

Caterpillar uses torx almost exclusively on the cab interior panels of anything built in the last 15 years or so. I wouldn't doubt that others do as well. You don't see them much outside of that, but they are certainly there. I certainly prefer them to #2 Phillips or JIS, as they don't have as much of a tendency to cam out when corroded or over torqued.

As far the fastener ID, I would say I'm generally 8/10 on a daily basis. With equipment and trucks, you're likely to find SAE and metric fasteners in close proximity, so mistaking a 9/16 for a 14 and a 3/8 for a 10 will happen. Always good to pay attention to the grade markings, so at least you know which rack to choose from.

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[rodsnratfinks]

I'm about 90% with most common fastener types. Bolt heads, hex cap, torx, etc. I do pretty well in both metric or standard (where applicable). My sockets are mounted open end up for fast ID.


Sent by an army of nefarious gnomes bent on world conquest.

 

[WWShop]

Terrible...almost everything looks 9/16 to me. It could be the size of a pinhead and i think to myself...9/16.

 

[ken w.]

I'm pretty good with automotive and small engine fasteners. It's a repetitive thing that just becomes a natural park of your day. Oil drain plugs kind of stump me though.

 

[bwringer]

99%+ on Japanese motorcycles, a little less on other metric machinery.

I've found that this talent can be astonishing or irritating to people who don't have it.

 

[Superbec]

I'm pretty good from 8mm to 19, after that it's luck and hit mis

 

[Al Bundy]

I'm pretty good at guessing the SAE size when the fastener is metric. Usually involves at least 3 trips to the tool box.

 

[JAKE-THE-TOOL-MAN]

having experience in automotive repair the oem fasteners don't often stump me, you tend to remember the common sizes the manufacture uses. Same goes for SAE up to 7/8th's since I have a few years of marine repair experience as well. Torx is a toss up as well as hex bits unless common sizes

 

[Jure]

10/10 (dealing with DIN metric only) 8,10,13,17,19,22,24 and 27. it aint easy to spot 11,12,14 and 18 hah

 

[anavrinIV]

Fasteners are either SAE, DIN or ISO, they almost never overlap unless some baffoon used random fasteners.

I'm guessing you've never worked on a Jeep TJ. My '05 has both metric and standard fasteners placed randomly around with torx and hex mixed in where they felt the need. Want to drop the transmission? Sure...you'll need a 10mm for the compressor bracket, 18mm for the skid pan bolts, 1/2" for the transmission bolts, 7/8 and 13/16 to remove lower control arm nuts (for a front skid pan), 8mm for the driveshaft, torx to remove the shift lever, and hex for the 2 upper transmission bolts.

 

[merr6267]

I thought myself pretty good at visual ID.

Then I took a break from working on cars for a bit and recently did an intake gasket on a 1995 Chevy K1500 with a 350 engine.

That was a nightmare of mixed fasteners. The engine (long block), being a legacy item was all SAE threads, with some of the accessories and attachments being metric. The real mess was that the accessory drive used metric headed screws while the threads were SAE. Some were mixed and different things were used in different places. That made my head spin.

Coming from the OE world, I understand why it's that way, it's just frustrating in the "mechanic" role.

The mixing is not random, as there were reasons for doing it that way and they involve using common drivers in the assembly line, the engine design was 40 years old and not changing, etc.

 

[Brian_WK]

Im good on 5/8 and below and 17mm and below. As long as I know before hand if im working on something that is Metric or SAE. Torx Allen I never know and is a complete guess.

Brian

 

[LXCam]

For years and years I was in the high 90's. But as my eyesight has gotten bad over the last 10 years I'd say I'm a 6 outta 10 and most of that is probably just experience. As much as my man card can't take the hit anymore I have to admit, I **** .

 

[sberry]

I have been doing it 51 years, we had a huge bolt collection when I was a kid I terrorized since I was about 5

 

[nadogail]

Size recognition, IMHO, is an acquired skill.

Back when I was in High School, '50s, I asked the old timers how they were able to know which wrench to reach for, I was told that I comes with paying attention and to keep practicing. I was told that eventually, if I tried, that skill would become mine.

Now, in the twilight of my career, I can still amaze unskilled helpers by that little bit of retained knowledge.

 

[PelicanPines]

This is why the invented the digital caliper

I almost always have this one in my pocket... I have spanned a number of fasteners and walked over to my wrench collection and held this caliper to find the right size... It's also helpful in hardware stores...

 

[APEowner]

I used to be great at it. I could also look at a wrench or socket and tell what size it was. Now that I don't work with tools everyday and my eyesight is getting worse I kind of **** at it. I was really bad when I was trying to get used to trifocals since they changed size when I moved my head. It's 9/16 nope, now it 1 1/8. Getting old is not without its downsides.

 

[panknuckshovel]

About a 2 out of 10. I get a lot of exercising walking back to the toolbox.

Same here, and when it turns out to be a metric that shouldn't be a metric even more trips and louder WTF's.

 

[Heavy Metal Doctor]

SAE -- 99% right from #8 to 1" thread size - even most times when there's an odd MFR that does the oversized head (like a 5/8" head on 3/8" bolt) I get it right on the first try.

Metric -- I'd say more along the lines of just better than 50% on stuff I have not worked on before. Repeat jobs I can usually remember the list of required tools and size hardware they go with.

As for recognizing SAE from Metrics -- are they not teaching how to tell grade markings anymore? Seems like every time the subject comes up, like the mixed applications such as metric mounting bolts for a component that uses an SAE drive that connects the two parts using SAE hardware, the other person acts like I'm the first guy who ever showed them bolt grade markings. Young or old, doesn't matter, they seem lost on this concept.

 

[R-Savage]

Not too bad I'll use SAE as my standard if it is inbetween then I guess it's metric. Would be cool if I could find a complete fractional wrench and socket set that included the inbetween sizes. I have been looking for these for a while. But at most three wrenches then. Shoot. It's metric.

 

[matemike]

This is exactly why I usually grab the ratchet and three or four sockets all around the same size. Usually it is one of the middles of the sizes I grabbed. I'm 9/10 using this method.

But then it also depends on how long I've been working with something, dare I say how intimate I've been with a piece of equipment. There a big difference in guessing the right sizes between a particular vehicle I own or if it's the first time in putting my hands on something. For instance if Im looking at my own truck or motorcycle that I've owned for 8 years then usually a quick glance will jog my memory and I know "that" bolt is a 10mm and so a glance at the next bolts tells me it's a 12mm, or 17, etc.

I don't use SAE as much as metric, but I'm usually pretty good at guessing a close size then narrowing it down to the most common size (7/16, 1/2, 5/8, 9/16 or 3/4) before I ever even open the socket drawer. I'm even better with metric guesses though for sure.

 

[thegroundpounder99]

Some days better then others lol.


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[dam427]

About a 2 out of 10. I get a lot of exercising walking back to the toolbox.

Ha ha. Same here. When I have to guess, I bring two or three. Saves on trips. Usually get it on the third trip.

 

[M6erfan]

Working on a lot of German cars and jap motorcycles (mostly older models) I'm really good at hex, torx, and 6-22mm bolts. I'd say I get it right more than 9 times out of 10

 

[coal_man]

Ha ha. Same here. When I have to guess, I bring two or three. Saves on trips. Usually get it on the third trip.

Me too. My old man has the gift though. He's probably a constant 9/10 on SAE.

coal_man

 

[slip knot]

Cresent wrench,channel locks, vice grips and BFH. I'm covered.

 

[GRX]

Chances of me selecting the right tool 1st time ...

> Fractional - about 99%

> Metric - never heard of it

> Whitworth - maybe 50/50

Here is one for you

 

[TheMadMech]

As an industrial mechanic at a plant where it's a grab bag of SAE and Metric I've gotten pretty good, probably 9/10 honestly. That said, about once a month I have an off day and can't seem to get the correct tool to save my life.

This is my clever signature.

 

[wombat31x]

It all depends on where the particular fastener is located, If it's in plain sight and easily accessible then I get it right 9 out of 10 times. However if it is located at the top of a ladder or underneath a dozer necessitating crawling underneath or climbing inside the engine bay then I get it right about 5 out of 10 having to make a trip down or out to get another size..haha