Newb question
- Thread starter Roof
- Start date
Mr.Nutcase
Well-known member
17mm, depends. I have same sockets in 1/2 and 3/8
It really depends on the torque requirements of the fastener you're tightening.
But the rule of thumb I always used was - if I had to go bigger than twice the drive size, it was time to move up to the next drive size.
So, the biggest 1/4" drive socket I'd use is 1/2"
With 3/8", it'd be 3/4".
Don't know if that'd hold true for 1/2" drive (and larger), as I've seen some big 1/2" drive sockets.
But the rule of thumb I always used was - if I had to go bigger than twice the drive size, it was time to move up to the next drive size.
So, the biggest 1/4" drive socket I'd use is 1/2"
With 3/8", it'd be 3/4".
Don't know if that'd hold true for 1/2" drive (and larger), as I've seen some big 1/2" drive sockets.
davesnothere
Well-known member
That depends on the bolt.
rockinacummins
Well-known member
Good question... Sorry I don't have an answer... I just kinda navigate towards one or the other depending on the task at hand...
DieselRiver
Well-known member
Typically if its a rusted or very tight fastener ill use a 1/2in breaker bar, i cant think why someone would use 3/8 breaker bars when theres 1/2in out there. Thats just me though 
. Personally im not sure why 3/8 impact wrenches exist either.
. Personally im not sure why 3/8 impact wrenches exist either.3/8 set at least through 19mm and 7/8 in SAE. Most 1/2 sets start at 10mm and 3/8 SAE.
As other's said, depends on the bolt and the torque applied to it. I've had need of a 1/2 socket on a 13mm bolt in the past. Big bolt, little head and had well over 100ft/lbs of torque on it.
The normal set sizes as I mentioned is a good starting point, but for reference, in the auto industry, you'll definitely do the high end of the 3/8 set regularly. Probably won't use the low end of the 1/2 stuff(10-14mm - 3/8-9/16) that often, but when you need it, you will be glad you have it.
As other's said, depends on the bolt and the torque applied to it. I've had need of a 1/2 socket on a 13mm bolt in the past. Big bolt, little head and had well over 100ft/lbs of torque on it.
The normal set sizes as I mentioned is a good starting point, but for reference, in the auto industry, you'll definitely do the high end of the 3/8 set regularly. Probably won't use the low end of the 1/2 stuff(10-14mm - 3/8-9/16) that often, but when you need it, you will be glad you have it.
nicksnothereman
Well-known member
It's arbitrary.
Use the torque values, but even if you do you can have large headed bolts with low torque (say...a drain plug). So you use what you're comfortable with. If I don't have a problem with the 1/2" fitting I'll use that even if it's overkill. But it's more or less what you're comfortable with and the quality of your tools and/or the quality of your warranty.
countryroad82
Well-known member
Typically if its a rusted or very tight fastener ill use a 1/2in breaker bar, i cant think why someone would use 3/8 breaker bars when theres 1/2in out there. Thats just me though
Meh, I like my 3/8 impact. It's really handy when tearing something down as it is small enough to get in most areas a 1/2 will not and it has the power to take **** apart (it's a Snappy). As of the OP as everyone has said, if it is a rusted mess, I'm going to grab the 1/2 drive... As long as I can get it in there. For the most part, I grab 3/8 for most of the work I do. If I run into something rusted up and I have the time to, I lay the slickem' to it and let everything soak for a few hours.
Last edited:
Like allot of folks here I have 8, 9, 10, 11, 12, 13 and 14mm sockets in all three
drive sizes 1/4", 3/8" and 1/2"... So it does depend on the torque of the fastener.
For the most part I will use...
4mm - 12mm ... 1/4" drive
10mm - 17mm ... 3/8" drive
14mm - 38mm ... 1/2" drive
24mm - 50mm ... 3/4" drive
The overlaps I will decide on by the look and type of fastener.
drive sizes 1/4", 3/8" and 1/2"... So it does depend on the torque of the fastener.
For the most part I will use...
4mm - 12mm ... 1/4" drive
10mm - 17mm ... 3/8" drive
14mm - 38mm ... 1/2" drive
24mm - 50mm ... 3/4" drive
The overlaps I will decide on by the look and type of fastener.
Choose a drive size (in inches) greater than the cubed root of (the torque in ft-lbs divided by 2000).
What a shortcut.
Have we as a society gotten so lazy that the average mechanic will no longer bother employing a fourier transform to calculate and properly select drive size based on the desired swing frequency and available radial spectrum???
P.S. Fastener of twice the drive size? Laughable... That rule of thumb will lead you to be missing one.
It was meant as a joke, but it is probably somewhere close to the mark.
the gypsy
Well-known member
Don't over think it, just grab whatever is available. If it is too big go smaller, if it is too small go bigger. If you grabbed a small ratchet and you are having problems and afraid to break the ratchet go bigger. It is that simple.
My reason is I am having a hard time finding an 11 mm 1/2 drive to complete a set. This got me thinking if 1/2 drive is too much on smaller heads i.e 10-13 mm . If I reach for the big dog am I more likely to just shear the head off instead of removing the fastner
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
rlitman
Well-known member
My 1/2" drive impact sockets start at 10mm. But I don't use the ones below 14mm that much.
Not because they'll shear parts, but because it's just bulky in the hand when I have 1/4" and 3/8" drive sets in the next drawer.
Not because they'll shear parts, but because it's just bulky in the hand when I have 1/4" and 3/8" drive sets in the next drawer.
I don't think there is any general rule, and it depends on the condition of the fastener. I would say that in US sizes, I routinely use a 3/8 on nuts from 7/16 through 9/16, and larger if they look like they will not be very tight. Also there are situations where I would not use a ratchet and sockets at all.
Conductor562
Well-known member
For me it really depends on the fastener. I have no problem using 19-22mm on a 3/8" in an engine bay, but on the suspension or undercarriage anything from 17 up is going to be on a 1/2" ratchet.
ibedayank
Well-known member
depends what I am working on if new or rusted and what to tourqe it needs