3/8 and 1/2 in preference
- Thread starter indestro
- Start date
nissan_crawler
Well-known member
common sense.
If you have a 7/8" socket on, and both feet braced trying to get a bolt out, it's probably time for a 1/2"
krusty the clown
Member Emeritus
there used to be guidlines for chosing drive size on wrights website.
rsanter
Well-known member
experience
how tight so I think the bolt is?
am I assembling it or breaking it down?
how much room do I have?
how much depth do I need?
bob
how tight so I think the bolt is?
am I assembling it or breaking it down?
how much room do I have?
how much depth do I need?
bob
i only ever use 1/2 if my MG31 wont shift it. no matter what the size.
although, if its a 24mm suspension bolt thats been in there for 100,000 miles on a taxicab then ill break out the 1/2" 2135qti straight away.
its all relative.
although, if its a 24mm suspension bolt thats been in there for 100,000 miles on a taxicab then ill break out the 1/2" 2135qti straight away.
its all relative.
cruiser808
Well-known member
As the others expressed, expirence. Probably at 5/8", but it depends on the status of the fastener and the manly man arms to complete the fundenmentals. dropping some kroil doesn't hurt too.
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HandyManny
Well-known member
Use the correct size tool for the job. Use the following as a rule of thumb:
1. 1/4" drive tools, maximum fastener size is 1/4"
2. 3/8" drive tools, maximum fastener size is 1/2"
3. 1/2" drive tools, maximum fastener size is 5/8"
4. 3/4" drive tools, maximum fastener size is 1"
5. 1" drive tools, maximum fastener size is 1-1/2"
**Fastener size is thread diameter.
This general rule of thumb has always served me well.
1. 1/4" drive tools, maximum fastener size is 1/4"
2. 3/8" drive tools, maximum fastener size is 1/2"
3. 1/2" drive tools, maximum fastener size is 5/8"
4. 3/4" drive tools, maximum fastener size is 1"
5. 1" drive tools, maximum fastener size is 1-1/2"
**Fastener size is thread diameter.
This general rule of thumb has always served me well.
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Moose-LandTran
Well-known member
Experience and when a 3/8" doesn't give enough torque.
volvo420coupe
Well-known member
A Jedi mind just "knows" what drive size to choose.
Uncle Buck
Banned
A man has to know his limitations.....................
HandyManny
Well-known member
Check my post above. If memory serves me well I believe I got that info from a Wright publication several years ago. At least I think it was from Wright.
This is a serious "you just know" deal isn't it?
3/8" is good for when for when whatever I'm doing used less than 65 ft lbs to be installed. Beyond that, I go for 1/2 inch. That's usually heavy duty R&R's, and suspension work though. Stuff where I'm guaranteed to be covered in grease.
3/8" is good for when for when whatever I'm doing used less than 65 ft lbs to be installed. Beyond that, I go for 1/2 inch. That's usually heavy duty R&R's, and suspension work though. Stuff where I'm guaranteed to be covered in grease.
krusty the clown
Member Emeritus
i looked on the wright site and it has changed, i could not find it.
handymanny's figure's may be from the wright article, as remember they were surprisingly low for me.
handymanny's figure's may be from the wright article, as remember they were surprisingly low for me.
Merkava_4
Banned
It depends on how lazy I'm "fillin" that day. I've used a 1/2" ratchet to bust loose a spark plug on a Briggs & Stratton. 
Fedwrench
ALLIANCE MEMBER
For me 1/2 drive is used mainly for lug nuts, brake caliper cross over brackets, and cradle bolts. Pretty much everything else on my fleet vehicles is either 1/4 or 3/8 drive.
wantedabiggergarage
Member Emeritus
If you feel resistance, with the 3/8" drive (and you have no air power available), you have two options; a breaker bar, or to go one drive size up.
GDA
Well-known member
1/4 drive up to 12mm in engine bay and interior
3/8 for 13 to 19mm
1/2 for over 19mm and....
3/4 drive for the big stuff
I will usually grab a 1/2 drive at 17mm and over when doing brake and suspension work. Most of the time and depending on access issues, I try to save my ratchets by using a 3/8 or 1/2 breaker bar when initially loosening a bolt thats 17mm and over.
3/8 for 13 to 19mm
1/2 for over 19mm and....
3/4 drive for the big stuff
I will usually grab a 1/2 drive at 17mm and over when doing brake and suspension work. Most of the time and depending on access issues, I try to save my ratchets by using a 3/8 or 1/2 breaker bar when initially loosening a bolt thats 17mm and over.
HandyManny
Well-known member
It is one of those "you just know" type of things. The table I posted above was something I came across years ago and cliped it out to tape on a shelf above a workbench. Basically to point someone to in case they came asking for concrete reasons. I never really referenced it because experience points you in the right direction, usually. You're right, it's just one of those thing you kinda know.
These are good guides but I also look at the torque required like front wheel drive nuts big diameter but not a lot of torque. Wheels on large truck lug nuts are a lot tighter.
greenreese
Well-known member
- Joined
- Aug 10, 2009
- Messages
- 133
65ft-lbs seems pretty spot on to me. That's about where I got for a 1/2in too.
ZRX61
Well-known member
Maybe if you work on Marine engines, but those guidelines don't fly around aviation..
Moose-LandTran
Well-known member
I dunno ill say different but I bet we work on different things.
I use my 3/8 mg325 for everything up to 21mm. 99% of the time it loosens them without any struggle. (I know most caliper brakets I work on should be tourque around 80-100 and those are 18mm and I use the 3/8 impact)
I work in the automotive field.
HandyManny
Well-known member
Certified A/P mechanic as well as a Flight Engineer and ATP. Worked on them and flown them, both professionally. Pretty sure I know my way around the systems of a airplane. That guide applies to most powerplants and engines. No it isn't something I ever referenced much once I started wrenching, just always kept it around in case some newbie or some curious joe came asking general questions. I hate to be the type of guy who's answer to everything is uhhh I don't know. Someone here wanted to know, so I posted it. Even if some disagree. Then again your remark so far is the only contribution I've seen from you on this particular subject. Care to share something useful? Granted I will admit I haven't turned a wrench on an aircraft in over 30 years, and didn't do it very long back then either, but gee...
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Mr.Nutcase
Well-known member
Is this a real question? 1/2 for heavy work(ie suspension/brakes/..... 3/8 for general work(engine)..... 1/4 for small stuff.(electrical, interior..
Moose-LandTran
Well-known member
Just use whatever works and is comfortable for you to use. Obviously you don't use a long 1/2" ratchet to tighten 10mm nuts on battery terminals. Common sense/experice/whatever.
If it's really that hard to figure it out maybe you shouldn't be fixing cars, and your "skill set" is more suited to something like washing dishes.
If it's really that hard to figure it out maybe you shouldn't be fixing cars, and your "skill set" is more suited to something like washing dishes.
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Mr.Nutcase
Well-known member
He is right... Common sense/experice/whatever.....Just use whatever works and is comfortable for you to use. Obviously you don't use a long 1/2" ratchet to tighten 10mm nuts on batter terminals. Common sense/experice/whatever.
If it's really that hard to figure it out maybe you shouldn't be fixing cars, and your "skill set" is more suited to something like washing dishes.
and on cleaning dishes///