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What socket size to change drive size...

pugglewuggle

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Oct 26, 2018
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TX
At what socket sizes do you guys switch from 1/4" -> 3/8" -> 1/2" -> 3/4" drive?

I'm curious about both SAE and metric numbers.

Seems like the socket sizes/drive overlap quite a bit. Example: 3/8" socket with 1/2" drive. Also, 1" socket in both 3/8" drive and 1/2" drive. I'm asking "why!?"
 
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kctyphoon

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Jun 9, 2014
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Not sure theres really a rule.. i think its more about whats laying in front of you, and when you FEEL like you need the extra beef - all depending on what youre doing.
 

M6erfan

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'Merica!
I use 1/4" drive up to 14mm, 3/8" up to 22mm, 1/2" up to 32mm.

I don't use SAE, sorry.
 

Mr Ratchet

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I have and use all four drive sizes. I don't have a cutoff rule for drive size/socket size. Space constraints and torque are what determines the drive/socket size combination.

Seem like this has been a popular question the last month.
 

jblnut

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I have 1/2 drive sockets that go down to 3/8 and up to 1-5/16" and use 1/2 wherever I can as my 18v impact is 1/2" drive and it is a joy to use.

We use 3/4" drive on a few things but use 1" drive on most wheels and duals on the farm. When you have a 1-7/8" head on a lug nut that needs to be torqued to 950ft/lbs you need to bring out the big guns. 1" drive breaker bar, 6' pipe and a bathroom scale to get the amount of force needed dialed in. Give or take 160lbs, or the scale showing 80lbs when my fat a$$ is leaning on the pipe, is about right in that instance :lol_hitti
 

plinker

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Northern Wi
The torque needed to install or remove a nut/bolt is typically what prompts deciding what tools to use. Rust complicates this for the removal end of things. Access also contributes to this as it can be easier to spin a fastener in with a 1/4 drive ratchet and then use a 3/8 for final torque.

Some socket sizes may not make a lot of sense, (1/2 drive 3/8, 10mm ete...) but I'd rather have them then not as you never know what you're going to run into, such as using a 40" 3/4 drive ratchet to remove 3/4 lug nuts.

Larger 3/8 drive sockets (over 3/4 or 19) can be used for low torque situations without using an adapter. Same applies to other drive sizes too. For instance, I've used 15mm sockets in 1/4, 3/8 & 1/2 drive for various needs.
 

AceofSpad3s

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below 7/16 or 10mm I am probably using 1/4, above that I don't see a clear difference in tendencies and it depends on the torque application. When I was replacing calipers last year, I was using something 14 or 15mm ish in 1/2 drive (and sheared every bolt off), and probably wouldn't have wanted to do it with 3/8.
I rarely use 1/2 SAE at all but metric wise I see no reason not to have 10mm and up in half inch drive. 3/8 I think I have up to 21mm but I think I have only used up to 19.
Unless it's becomes awkward to use either due to the ratchet and socket being too large and cumbersome (1/4 head machine screws on a 3/8 drive) or a grossly oversized socket on a drive size that risks snapping or hurting yourself from (like using a 1/4 15mm to remove a caliper bolt), it isn't that big of a deal as people would make it out to be.
 

PugetDude

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No hard and fast rule, but I usually look for the next size up at about twice the drive size.
1/4" drive=sockets up to about 1/2"
3/8" drive= sockets up to about 3/4"
1/2" Drive= sockets up to 1-1/8"; I rarely use anything bigger than that.
 

ex-x-fire

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Sheboygan Falls Wi.
It depends on what you're working on, lets say you need to change a starter or alternator. The mounting bolts might be 13mm but the wiring hardware might be 13mm too. I'd use 1/4 & 3/8 on this job.
 

Fluelikesymptoms

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Apr 19, 2019
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Midwest snow belt
I have and use all four drive sizes. I don't have a cutoff rule for drive size/socket size. Space constraints and torque are what determines the drive/socket size combination.

Seem like this has been a popular question the last month.

+1

I've used the same socket size in a different driver sizes depending on the application, requirements, and constraints.
 

CR888

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Feb 19, 2017
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Someone posted in another thread a 'rule' (lol) which I thought made good sense that was along the lines of fastener thread size not head size where he said when the diameter exceeds 50% of the drive size, he moves up to the next drive size. Which is similar to what others have said about torque and fastener size I suppose. I wish I had more overlap in my socketry like 1/4" sockets that went up to 16mm+ as it just gives you more options in the rare occasions when you need them. I'm a sucker for oddball sockets though.
 

Mr Ratchet

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Michigan
The sets will tell you. For example, if 1/4 drive set 112TMMY goes from 5mm to 15mm, it's time to step up to 3/8 drive for 16mm.

https://store.snapon.com/Shallow-mm...hallow-Socket-Set-5-ndash-15-mm--P646461.aspx

But, what if he has the 3/8" drive set 212FSMY that goes from 8mm to 19mm.

That's eight sizes of over lap from 8mm to 15mm. Which set do you listen to when they both tell you to use them in one of these sizes. Then there is 1/2" drive set 323SWM. When do they get their say other than 20mm and up.
 
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zmotorsports

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No real rule per se. I use more of experience and application to drive my decision on what to use.

For small engines I can use my 1/4" much more than automotive of same sizes. On occasion when I grab a 1/4" or 3/8" and they seem to be much tighter than expected or just don't "feel" right I will jump up a drive size but again, more by feel than a general rule thing.
 

Strouty

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Mar 21, 2010
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Southern Maine
I almost always try and use the smallest drive size possible, even when I go from 1/4" drive to 3/8" drive most times I use the same size ratchet. In the end it depends on clearance, strength of the tools, and how I feel.
 

APEowner

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Oct 2, 2009
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Sunny, New Mexico
I don't have a rule. Working on cars and trucks I generally use a 3/8" drive unless I need more leverage in which case I'll switch to 1/2" or more room in which case I'll switch to 1/4" If I'm doing automotive interior work and industrial instrumentation I may use 1/4" for everything.
 

Empty Pockets

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Rural New York
I have no hard and fast rule, My 3/8 drive is usually the first that I go with. 3/4 drive is reserved for my New Holland tractor and accessories, 1/2 is for stuff that needs more torque than 3/8 would be prudent
 

DIY_Guy79

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Apr 30, 2019
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Tulsa, Ok
Is this a thing? I just use whatever seems to fit the job best. If I need a small socket/ratchet I go with 1/4". If I need something that I can really put some torque on I go with 1/2". And for most things, I just go with 3/8"... That's provided I cant get a power tool on it, of course.. My Makita Impact Driver with a socket drive adapter is what I do most of my wrenching with now-a-days, either that or my cordless ratchet.
 

tutti57

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Mar 26, 2018
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Whatever fits and is most convenient.

Sent from my Moto E (4) Plus using Tapatalk
 

rob67

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Sep 17, 2013
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Vienna, Austria
Someone posted in another thread a 'rule' (lol) which I thought made good sense that was along the lines of fastener thread size not head size where he said when the diameter exceeds 50% of the drive size, he moves up to the next drive size. Which is similar to what others have said about torque and fastener size I suppose. I wish I had more overlap in my socketry like 1/4" sockets that went up to 16mm+ as it just gives you more options in the rare occasions when you need them. I'm a sucker for oddball sockets though.

Bolt size vs. drive size seems to make a lot of sense, however 50% diameter seems low. Why not use a 1/4'' socket on an M5 bolt with an 8mm head or even M6 bolt with a 10mm head? I think if the bolt size is smaller than the drive size you should be fine.
 

Rickster

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Jun 26, 2005
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SE PA
In SAE; 3/8 or 7/16 is where I transition from 1/4dr to 3/8dr. 1/2dr over 3/4 mostly.
 

MattT

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Feb 20, 2010
Messages
3,201
Bolt size vs. drive size seems to make a lot of sense, however 50% diameter seems low. Why not use a 1/4'' socket on an M5 bolt with an 8mm head or even M6 bolt with a 10mm head? I think if the bolt size is smaller than the drive size you should be fine.

IME bolt diameter = drive size is when you'll sometimes need to step to the next drive size. For example 3/8" drive will usually work with 3/8"/M10 fasteners but you'll need to go to 1/2" for the really stubborn ones.
 
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