Standard vs Metric. Do we need both?

[Souljer]

Hi,

I've always wondered how necessary it is to have standard sets when metric sets cover the same sizes.

Don't they? I mean they can't be off more than a millimeter, right?

Are the fractional sizes somehow off just enough to require a full standard set of sockets and wrenches, etc. and a full metric set or could you do the same work (or near enough) with mostly metric equivalents? Maybe a few filling in spaces that are just off too much, but mostly metric.

Was wondering what the pros, pro-am class and DIY-ers think.

 

[canuckian]

I'm just a DIY'er and I definitely need both. If you work on a lot of older stuff that's SAE with metric tools, you'll round off a lot of fasteners. a mm or so difference can make all the difference in the world. That being said, if you only work on newer stuff that has all metric fasteners, you'll get by just fine with metric only. I'd still have at least a set of 3/8 sae sockets or basic set of SAE combination wrenches on hand just in case.

 

[Kurn]

Unless you have a low budget,having both means more tools! I know 3/8 has no equivalent,among others.

 

[Nick6]

Even though I use metric about 90% of the time I do have the odd item that requires SAE.

 

[930dreamer]

A roll-a-way for each.

 

[shoturtle]

depends on where you live, you may never need SAE. But for around the house in US, SAE is still the dominating standard for fasteners. But on cars more and more are metric. But that .3 mm can mean the difference of stripping a fastener and spending time removing it or get on and off without any issues. If you live in the US, you will need both if you work around your house.

 

[RECox286]

For the most part, metric and SAE are different up to 3/4" then they seem to be in

agreement for some reason.

Uncle Bob

 

[mrbreezeet1]

Unless you have a low budget,having both means more tools! I know 3/8 has no equivalent,among others.

This,
and what is an 18mm in standard, I don't think there is one.
5/8 close to 16 mm, 19 REAL close to 3/4, but it's really best to have both.

 

[chris142]

A 14mm is too small to fit on a 9/16 bolt head and 15mm is too big.

I have both sets and I use both daily, but the metrics more.

 

[pipsters]

A mm tool that is off by anything over 0.2mm will start to round the bolt when you put pressure on it.

 

[scw1991]

If you own a later model American GM, Ford, or Chrysler assembled car, you better have both!

 

[ajchien]

DIYer and I've never thought of only going with just one. Other than 3/4=19mm or 5/16=8mm, I find substituting them to be a recipe for rounding off bolt heads. I'm already an expert at rounding bolt heads, I don't need any added help. If I were not going to care whether it was metric or standard, and not care about reinstalling the bolt, I might just consider an adjustable wrench, channellocks or vise grips.

If you must have only one I might consider those metrinch or spline drive types, but I have no experience with those at all.

When I work on cars, it's mostly metric. When I work on the house, it's usually SAE.

 

[Humble Mechanic]

Like others have said, it really depends on what you are doing. At work I have99% metric tools. Not many standard sized fasteners on the VWs!

I do have some of both at the house.

 

[OccupantRJ]

A roll-a-way for each.

This is what I do in my home shop, one for each.

 

[Hetman]

DIYer and I've never thought of only going with just one. Other than 3/4=19mm or 5/16=8mm, I find substituting them to be a recipe for rounding off bolt heads. I'm already an expert at rounding bolt heads, I don't need any added help. If I were not going to care whether it was metric or standard, and not care about reinstalling the bolt, I might just consider an adjustable wrench, channellocks or vise grips.

If you must have only one I might consider those metrinch or spline drive types, but I have no experience with those at all.

When I work on cars, it's mostly metric. When I work on the house, it's usually SAE.

There's also 5/32"==4mm and 5/64"==2mm when it comes to allen .

Over 1" you can grab nearest metric if you have every 1mm, it will fit for emergency work.

 

[tpolley]

If you buy anything from harbor freight you need both. They skip over stuff and the tolerances are so sloppy I just go until I find one that fits. What pisses me of is I NEVER have a swivel impact socket in the size I need.

 

[Skin]

Hi,

I've always wondered how necessary it is to have standard sets when metric sets cover the same sizes.

Don't they? I mean they can't be off more than a millimeter, right?

Are the fractional sizes somehow off just enough to require a full standard set of sockets and wrenches, etc. and a full metric set or could you do the same work (or near enough) with mostly metric equivalents? Maybe a few filling in spaces that are just off too much, but mostly metric.

Was wondering what the pros, pro-am class and DIY-ers think.

1mm is alot of play. Good way to destroy things. Next time you're working on something metric instead of using the correct size go 1mm over and see how well that works for you. You'll want standard sockets and wrenches if you work on one of the big 3. I know Dodge was still using a mix not too long ago on a few limited locations when it came to pick-ups.

 

[emeraldcoupe]

i need both.

my car is a '66 mustang

truck is an '03 dodge

 

[JKady]

They don't really cross over as much as you think. I'm a full time tech, and I don't carry anything SAE aside from a set of standard wrenches (from 1/4-1", and 13/16-1" ratcheting) on my service cart but I often pull from both sides of that wrench drawer. Lots of late model American cars (especially Mopars) use a mix of both.

 

[nanofrog]

Just a DIY'er, but most I own is metric (cars I have are all metric). I do keep a smaller selection of SAE though, which are needed on occasion (just some wrenches and shallow 3/8" DR. sockets in smaller sizes).

I'd love to have a full compliment of both, but it's too expensive for how infrequently I'd use them.

 

[malibu101]

Just get this Metrinch set and you're covered for both SAE and metric.

Quote from the below link- "The patented Metrinch Wall Drive profile drives only on the flats and not on the corners. The dimensions of Metrinch sockets and spanners have been precisely calculated, so that a single Metrinch tool will operate on both metric and inch series fasteners."

http://www.metrinch-tools.com/website/introductie.php?subnr=1

The above tool recommendation is said kiddingly.

 

[Harwinton]

I almost never encounter metric fasteners on my 1994 Jeep Wrangler. Most of the other things I service use SAE nuts and bolts as well. But I did recently find metric nuts in a place I did NOT expect--the new spigot for my kitchen sink had them!

The carb on my Cub Cadet garden tractor had a couple too. Kinda odd; the rest of the machine's got mostly 1/2" and 7/16" nuts and bolts. And there's a couple scattered on my Jeep here and there but I haven't run into too many yet.

It pays to have at least basic sets of both. Different sized nuts and bolts have a way of popping up out of nowhere. I know when I was changing out my spigot I was wanting some metric wrenches.

 

[MarkH]

I think the Metrich size chart says it all. The ones close have fit both. Some fit really nothing made except metric recently. The old 32's in tool sets are long gone even in the country. I think they were 19/32 and 23/32 it is hard to remember.

MET-1108 Wrench 8mm & 5/16"
MET-1109 Wrench 9mm & 11/32"
MET-1110 Wrench 10mm & 3/8"
MET-1111 Wrench 11mm & 7/16"
MET-1112 Wrench 12mm & 15/32"
MET-1113 Wrench 13mm & 1/2"
MET-1114 Wrench 14mm & 9/16"
MET-1115 Wrench 15mm & 19/32"
MET-1116 Wrench 16mm & 5/8"
MET-1117 Wrench 17mm & 11/16"
MET-1118 Wrench 18mm & 23/32"
MET-1119 Wrench 19mm & 3/4"
MET-1120 Wrench 20/21mm & 13/16"
MET-1122 Wrench 22/23mm & 7/8"
MET-1124 Wrench 24mm & 15/16"
MET-1126 Wrench 26/27mm & 1 1/16"
MET-1129 Wrench 29/30mm & 1 3/16"
MET-1132 Wrench 31/32mm & 1 1/4

 

[wafrederick]

GM 3800s are half and half,has standard and metric bolts.The GM 4.3s,went to metric bellhousing and starter bolts in 2000.The book shows the 1996 to 1999 4.3s differant,a 2000 and up will fit and the only 2 differances are the metric bellhousing and starter bolts.

 

[Jim C.]

Even though I use metric about 90% of the time I do have the odd item that requires SAE.

I'm the exact opposite of this. I use about 90% SAE and 10% metric.

Jim C.

 

[shoturtle]

For US home and older US cars, that is about right. But with newer US cars, the need for metric is increasing. Friends of mine have went closer to 50/50 as they are diyer's.

 

[Jim C.]

I think the Metrich size chart says it all. The ones close have fit both. Some fit really nothing made except metric recently. The old 32's in tool sets are long gone even in the country. I think they were 19/32 and 23/32 it is hard to remember.

MET-1108 Wrench 8mm & 5/16"
MET-1109 Wrench 9mm & 11/32"
MET-1110 Wrench 10mm & 3/8"
MET-1111 Wrench 11mm & 7/16"
MET-1112 Wrench 12mm & 15/32"
MET-1113 Wrench 13mm & 1/2"
MET-1114 Wrench 14mm & 9/16"
MET-1115 Wrench 15mm & 19/32"
MET-1116 Wrench 16mm & 5/8"
MET-1117 Wrench 17mm & 11/16"
MET-1118 Wrench 18mm & 23/32"
MET-1119 Wrench 19mm & 3/4"
MET-1120 Wrench 20/21mm & 13/16"
MET-1122 Wrench 22/23mm & 7/8"
MET-1124 Wrench 24mm & 15/16"
MET-1126 Wrench 26/27mm & 1 1/16"
MET-1129 Wrench 29/30mm & 1 3/16"
MET-1132 Wrench 31/32mm & 1 1/4

I don't know about all the other size equivalencies, but after a lot of experience restoring some old woodworking machinery, I can say with a high level of confidence, that 20mm is exactly 25/32".

Jim C.

 

[zjrog]

Although I don't have a vehicle for SAE fasteners, right now... I prefer to keep SAE and Metric. Hmmm, separate cabinets for Metric and SAE is doable at this stage... Might resolve a couple current packaging issues.

 

[pjb]

My 97 F350 needs both. My JD 318 is a real nightmare, the fender deck has 3 half inch bolts and one 13mm bolt. To get the air filter box off the carb it is mix and match.

Mine has electronic ignition and don't know if the earlier ones were all SAE or not. My JD 214 is all SAE and I can't swap front rims because the 318 has a metric axle.



Patrick

 

[malibu101]

I don't know about all the other size equivalencies, but after a lot of experience restoring some old woodworking machinery, I can say with a high level of confidence, that 20mm is exactly 25/32".

Jim C.

Actually 20MM=.7874
and 25/64= .7812

So yeah .0062 is almost not even noticeable.

 

[archirelic]

DIYer here and I need both. I've got a 78 Dodge Ramcharger, 03 Chevrolet Silverado 1500, and an 04 Oldsmobile Alero [wife's vehicle]. And for a good many years, I had a 1991 Mitsubishi Montero till I gifted it to my youngest brother for his daily driver.

I also forgot to mention the fact that I do a lot of demo work, renovation work, and remodeling. So I encounter both there as well.

 

[1stblack97ZJ]

My jeep needs both, plus I work on a lot of lawn mowers, weedeaters, tillers, etc... So I use both about equally.

 

[davesnothere]

I think this thread is retarded. Not only do you need metric and sae, you also need bsw.

 

[Charles (in GA)]

I think this thread is retarded. Not only do you need metric and sae, you also need bsw.

I agree, you need whatever is needed to do the job properly, be it metric, fractional, whitworth, or martian space craft hardware sizing. Just get it and quit worrying about it.

Charles

 

[Steevo]

Hi,

I've always wondered how necessary it is to have standard sets when metric sets cover the same sizes.

Don't they? I mean they can't be off more than a millimeter, right?

Are the fractional sizes somehow off just enough to require a full standard set of sockets and wrenches, etc. and a full metric set or could you do the same work (or near enough) with mostly metric equivalents? Maybe a few filling in spaces that are just off too much, but mostly metric.

Was wondering what the pros, pro-am class and DIY-ers think.

Please tell me you are not a professional, who might someday work on my vehicles with "close enough" wrenches or sockets.

 

[trboxman]

I almost never encounter metric fasteners on my 1994 Jeep Wrangler. Most of the other things I service use SAE nuts and bolts as well. But I did recently find metric nuts in a place I did NOT expect--the new spigot for my kitchen sink had them!

The carb on my Cub Cadet garden tractor had a couple too. Kinda odd; the rest of the machine's got mostly 1/2" and 7/16" nuts and bolts. And there's a couple scattered on my Jeep here and there but I haven't run into too many yet.

It pays to have at least basic sets of both. Different sized nuts and bolts have a way of popping up out of nowhere. I know when I was changing out my spigot I was wanting some metric wrenches.

Wait till you change out u-joints and need that 8mm 12pt socket for getting the straps off and on....

 

[Wrenches of Death]

Hi,

I've always wondered how necessary it is to have standard sets when metric sets cover the same sizes.

Blame Gerald Ford, that savage.

He's the one that put us in that uh-Holy alliance with Satan and pushed us on down the metric path to hell and damnation with his Metrication Council.

Its publicly advertised goal was to make American products more appealing to overseas markets and help boost exports and create jobs if I remember right. We now know that its real purpose was to make foreign protects more readily accepted here and destroy the industrial capabilities of the US along with it's economy with the end result of enslaving us. Yes, enslaving us to people that use the metric system.

Reagan saw it and tried to stop it, but it was too late. It had already started to snowball because of fifth columnists and agent provocateurs.

Remember, the metric system has been the preferred system of measurement of Communist countries and tyrannical regimes for a long time. Stalin used the metric system while he starved over three million Ukrainians to death. So did Hitler while he kicked off a war that ended up killing 30 million people. Mussolini might have made the trains run on time, but he did it and murdered people at the very same time he was using the metric system. Let's not forget the 7.7x58mm people that bombed Pearl Harbor. North Korea, the Land of the Perpetual Famine, uses the metric system. And old Mao did too.

'nuff said...

WoD

 

[WWIIjeep]

I think the Metrich size chart says it all. The ones close have fit both. Some fit really nothing made except metric recently. The old 32's in tool sets are long gone even in the country. I think they were 19/32 and 23/32 it is hard to remember.

MET-1108 Wrench 8mm & 5/16"
MET-1109 Wrench 9mm & 11/32"
MET-1110 Wrench 10mm & 3/8"
MET-1111 Wrench 11mm & 7/16"
MET-1112 Wrench 12mm & 15/32"
MET-1113 Wrench 13mm & 1/2"
MET-1114 Wrench 14mm & 9/16"
MET-1115 Wrench 15mm & 19/32"
MET-1116 Wrench 16mm & 5/8"
MET-1117 Wrench 17mm & 11/16"
MET-1118 Wrench 18mm & 23/32"
MET-1119 Wrench 19mm & 3/4"
MET-1120 Wrench 20/21mm & 13/16"
MET-1122 Wrench 22/23mm & 7/8"
MET-1124 Wrench 24mm & 15/16"
MET-1126 Wrench 26/27mm & 1 1/16"
MET-1129 Wrench 29/30mm & 1 3/16"
MET-1132 Wrench 31/32mm & 1 1/4

19/32 and 25/32 were the two most common. Really complete sets included 21/32, 29/32 and 31/32 too. I don't think 23/32 was ever offered by anyone.

For those of us who restore pre-'50s US vehicles or machinery, 19/32, 25/32 and 31/32 wrenches are still necessary at times.

I've never owned nor used a Metrinch brand wrench, but I can tell you that the chart doesn't work for all brands of wrenches. For example, neither my Proto nor my Snap-On 14mm wrenches will fit a 9/16" USS or SAE hex nut or bolt. Metrinch must make some of their wrenches with slightly larger openings to be able to interchange on some of those sizes.

 

[Souljer]

Hi,

Thanks for all the feedback. Great to hear so many points of view clearly pointing in one direction: Get Both - They are not interchangeable except in special cases, especially below 3/4".

I'm more of a DIYer at least in spirit. Right now I'm between garages. I still work on stuff but not automobiles or project cars right now. I helped out when I was learning and just borrowed my father's tools as we were working on his projects -auto and home. I had no tools of my own so I never thought about it. Later a home/ hobbiest but very experienced mechanic was helping me for fun, working on and maintaining my 1969 Triumph TR6. He had a TR4 that he'd replaced the whole drive train with Ford POWER.

This is when I started buying my own tools because I did not want to borrow his all the time. However, I only bought sizes and sets that applied to the Triumph. No metric. I always wondered in the back of my mind if I was buying into 'old and dated tech' buying a set of standard sockets rather than metric. I was following my old friends advise and he obviously steered me straight.

In the future, besides working on my 2002 Ford Explorer Sport, I'd like to someday get something like an International Scout II and/ or motorcycle to play with.

Thanks again.
I appreciate you curing my ignorance.

 

[TwoInch]

19/32 and 25/32 were the two most common. Really complete sets included 21/32, 29/32 and 31/32 too. I don't think 23/32 was ever offered by anyone.

For those of us who restore pre-'50s US vehicles or machinery, 19/32, 25/32 and 31/32 wrenches are still necessary at times.

I've never owned nor used a Metrinch brand wrench, but I can tell you that the chart doesn't work for all brands of wrenches. For example, neither my Proto nor my Snap-On 14mm wrenches will fit a 9/16" USS or SAE hex nut or bolt. Metrinch must make some of their wrenches with slightly larger openings to be able to interchange on some of those sizes.

metrinch tools are 12 point sockets, or actually double hex sockets with one hex being one size in metric, and one hex being standard. with out close inspection they appear to be just 12pts, but they arent.

after looking, it appears they now use a lobed style, which is another design that fits a standard and metric. the picture above is apparently the original design i was familiar with.

the chart a couple posts above is not a chart for any other brand, and the sizes are not interchangeable as the chart shows.