I feel your pain. I'm overhauling a 4055 right now. I had to use 1/4, 3/8, 1/2, and 3/4" drive socket sets. Had to use 6 and 12 point sockets while looking at markings on the bolts to determine metric or SAE.
Why do Metric socket sets skip some sizes?
- Thread starter rogersmithiii
- Start date
I feel your pain. I'm overhauling a 4055 right now. I had to use 1/4, 3/8, 1/2, and 3/4" drive socket sets. Had to use 6 and 12 point sockets while looking at markings on the bolts to determine metric or SAE.
ToolPolisher
Well-known member
- Joined
- Jan 21, 2017
- Messages
- 195
All the T-Bolt clamps I can remember have been 11mm from the factory. Given I have spare hardware on hand I change them to the more common 10mm size as they are both internally 6x1.0 threaded.
Lucid Moments
Well-known member
My issue is that I never know what I am going to be working on. I am no kind of pro but because of that I end up with some oddball stuff sometimes. And while I can certainly go to the store to get what I need it annoys me to have to stop to go buy a tool. I would much rather buy the tool ahead of time and be ready to go.
Busted_Knuckles
Well-known member
I live rather rural, my main line is stand by generators, I also do industrial power tools, transmissions, powertrain, some general auto,... old enough that I no longer remember exactly what I used what size on, keeping in mind, I work on the same model of anything rarely twice.
That said, in the last year I replaced ALL my socket sets with Tekton, and maybe what put me over the top, was complete sets of sockets.
I about come out of my mind, when I dont have a socket to pull something apart. No store to drive too, to pick up a missing socket as well. Im OCD about socket management, out of necessity.
Thinking its a brilliant marketing strategy for Tekton, I do not even want to begin to try and figure out, what sockets I might NOT need in the future, just sell me the complete sets,... if I never use a socket, fantastic,..
That said, in the last year I replaced ALL my socket sets with Tekton, and maybe what put me over the top, was complete sets of sockets.
I about come out of my mind, when I dont have a socket to pull something apart. No store to drive too, to pick up a missing socket as well. Im OCD about socket management, out of necessity.
Thinking its a brilliant marketing strategy for Tekton, I do not even want to begin to try and figure out, what sockets I might NOT need in the future, just sell me the complete sets,... if I never use a socket, fantastic,..
Spider Curry
Well-known member
It was decades ago and my brain is probably rusty, but having torn apart my fair share of Pontiac Fieros, I recall nearly every bolt and nut in those cars were 9/11/13 mm. I started working on the Plastic Fantastic Fun Car after years in the F-body world. In those days when GM seemed to switch between SAE and metric every other bolt location, it was a real pleasure to have only 3 combination wrenches, 3 sockets, and a ratchet to keep track of.
I also hate this. Always end up needing one not in the kit and end up digging through the loose socket drawer for 10 minutes. I recently bought a made in USA Proto J72206 19 piece 3/8" drive impact set. Has 6 through 24mm with no skips. No skips was a requirement when I was shopping for this set. I would rather have it and not need it then to need it and not have it.
Garcky
Well-known member
16mm = 5/8" Of course, I have both sizes. 8mm = 5/16", too. Either way.
VolvoRyan
Well-known member
Depends on your jam. If you live in DIN or JIS, you may be happy with skipped sizes. Volvo's used AW (basically, Toyota) transmissions for 40 years. 6mm-24mm (except 23mm) will find a use.
Skips are nice above 24mm.... but I shop piecemeal anyway.
-Ryan
Skips are nice above 24mm.... but I shop piecemeal anyway.
-Ryan
jayemm
Well-known member
In an effort to eliminate surprises from skipped sizes, I got a 10-24mm inclusive set in deep impact sockets. My front strut to knuckle nuts are 23mm on a 21mm bolt head. Not concerned with anything bigger. Over the years, some odd/rarely used sizes I remember are:
GM dash lower covers --- 7mm screw head
GM fuel filter-- 20mm nut on one end of filter
GM - sintered fuel filter nut on side of carburetor -- 1"
Floor jack packing/seal nut on plunger --24 mm ( had to gently hammer a 15/16" open end wrench on that)
There have been others.
GM dash lower covers --- 7mm screw head
GM fuel filter-- 20mm nut on one end of filter
GM - sintered fuel filter nut on side of carburetor -- 1"
Floor jack packing/seal nut on plunger --24 mm ( had to gently hammer a 15/16" open end wrench on that)
There have been others.
Debcrow
Well-known member
When American manufacturers first started to finally be forced to use metric fasteners they seemed to resist using 'common' sizes. My Ford had several places they used 15 mm instead of 14 mm. Chevy van had 9 mm on AC compressor instead of 10 mm. ETC.
There are a bunch of situations where having no skips is great:
- Using a metric socket on an SAE fastener and vice-versa (saves a trip back to the toolbox on occasion).
- Going one-size up or down on a rusty or worn fastener.
- It gives you a sense of inner calm and completion.
- Especially with larger fasteners with loose tolerances, sometimes a smaller size provides a tighter fit.
- You don't need the oddball sizes until you work on something weird. 11mm fasteners exist, even if people can live their entire life without seeing one.
- When using your sockets for un-socket things, pressing in a seal for example, those skip sockets might be just the right size.
Dave455
Well-known member
7mm is fairly standard - ISO and DIN nut size for an M4 bolt.
Similar story with 24mm - ISO and DIN for an M16.
20mm is a right pain - think I might own one but don’t think I’ve ever used it.
I tend to view oil filters as a special case - one of my BMW’s needs a 36mm just to remove the oil filter! Some regular guy without 3/4” drive is going to need to invest in special tools just to do an oil change, but I suppose BMW want to make it as awkward as possible!
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Dave455
Well-known member
Yes, when the U.S. started adopting metric fasteners it evolved it’s own standard, ANSI Metric. Although some of the sizes are common to other standards, the 15mm is unique (as regards standard fasteners).
Personally, as a Brit, I hate the U.S. going metric. Historically, I can find any piece of American equipment, from a WW2 Jeep, through to a Caterpillar, and know which spanners I will need (same ones I use on most domestic classics).
If I need a bolt I can just grab one from the stores - could be one of my Grandfathers for the Diamond T, or one I bought last week, doesn’t matter.
Now, who knows, and it’s supposed to be in aid of standardisation. Or is all in aid of saving a few cents…!
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15 mm has been the standard size for bike axle nuts for decades.
Dave455
Well-known member
…as regards standard fasteners…!
When you get to axle nuts, oil filters, or pretty much anything other than a regular nut / bolt you can pretty much find any size. Think I can recall 15mm on a Citroen belt tensioner too.
This is the biggest argument for having a “non skip” set of wrenches / sockets.
I have some tools I leave on my vehicles, and I’m happy to just include the sizes they use, but in my “grab and go” road box, I have very few skips now - 20mm is one though!
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I need all the sizes because I **** at identifying a size just by looking at it.
I gotta grab a fist full of metrics and standards that are close and see what fits.
My dad can look at a nut and be like "yeah that's a half" and I'm all "it might be a half or 9/16 or maybe 32mm."
I gotta grab a fist full of metrics and standards that are close and see what fits.
My dad can look at a nut and be like "yeah that's a half" and I'm all "it might be a half or 9/16 or maybe 32mm."
My best guess…
Old metric sets were built around VW, and DIN sizes. So 10, 13, 17, 19mm.
At the time, they also tended to skip sizes where there were ‘close enough’ inch sizes 11mm, 16mm, even basic sets sometimes didn’t have 19 because everyone was assumed to have 3/4”.
Over the years flange bolts have become more common, and so has JIS. And GM and Ford had their own take. So 12, 14, 15, 18mm are now relevant too.
Tool makers have put sets together with a blend of past practice, intended use, and target price. But the right answer for anyone here is no skips.
Inch sizes changed a bit over time too - 19/32 and 25/32 were supposedly common many years ago. 11/32 is often skipped. And often it is the large/small end of a SAE set that is skipped (like a 1/4” set ending at 7/16 instead of 1/2 or 9/16).
There’s bound to be specific applications where every size is needed. If not a bolt, a custom fastener. I know pro mechanics on here sometimes say they never use 9mm, but I’ve definitely used on brake bleeders.
Old metric sets were built around VW, and DIN sizes. So 10, 13, 17, 19mm.
At the time, they also tended to skip sizes where there were ‘close enough’ inch sizes 11mm, 16mm, even basic sets sometimes didn’t have 19 because everyone was assumed to have 3/4”.
Over the years flange bolts have become more common, and so has JIS. And GM and Ford had their own take. So 12, 14, 15, 18mm are now relevant too.
Tool makers have put sets together with a blend of past practice, intended use, and target price. But the right answer for anyone here is no skips.
Inch sizes changed a bit over time too - 19/32 and 25/32 were supposedly common many years ago. 11/32 is often skipped. And often it is the large/small end of a SAE set that is skipped (like a 1/4” set ending at 7/16 instead of 1/2 or 9/16).
There’s bound to be specific applications where every size is needed. If not a bolt, a custom fastener. I know pro mechanics on here sometimes say they never use 9mm, but I’ve definitely used on brake bleeders.
msharley
Well-known member
18mm for some GM lug nuts (and other ****)
5.5 for Ford ignition module.
4.5mm (special wrench) for FoMoCo headlight adjustment. (for Fords? you need one of every wrench ever made, two of most)
MBfreak
MEMBER EMERITUS
SAAB is fortunately now dead. And Buried. About the worst built cars in the world.
One example is the 4 cyl they made in the end of the sixties. Thermostat was placed between engine block and cylinder head for someobscure engineering decision. Replace thermostate: first remove the cylinder head.
Or, take the gearbox out of a SAAB 9000. Remove several parts of the suspension, drive shafts and subframe, ad then you need sockets from 10 to 19 mm to unbolt!
Anothe beauty is the lambda sond plug-in contact. Sond in front on the exhaust manifold. Wire snuck around the block to a contact that sits high up in the block, well hidden by various parts. Like the intake manifold with 8 short pieces of rubber hose and 16 hose clamps.
What´s not to like??
Good riddance.
ONE good fact. The swedish govt crash statistics show that the body is extremely well designed and manufactured. Injury statistics from real accidents very low
Ola
One example is the 4 cyl they made in the end of the sixties. Thermostat was placed between engine block and cylinder head for someobscure engineering decision. Replace thermostate: first remove the cylinder head.
Or, take the gearbox out of a SAAB 9000. Remove several parts of the suspension, drive shafts and subframe, ad then you need sockets from 10 to 19 mm to unbolt!
Anothe beauty is the lambda sond plug-in contact. Sond in front on the exhaust manifold. Wire snuck around the block to a contact that sits high up in the block, well hidden by various parts. Like the intake manifold with 8 short pieces of rubber hose and 16 hose clamps.
What´s not to like??
Good riddance.
ONE good fact. The swedish govt crash statistics show that the body is extremely well designed and manufactured. Injury statistics from real accidents very low
Ola
toplessHO
Well-known member
I found that 11/32" is used on PSC motors alot. You change blower motors on residential - you'll need that 11/32". As it is often skipped I assembled a nice selection of various wrenches and sockets in that size just to deal with electric motors and brackets.
Can't say if recent motors out of China and Mexico have gone metric on those nuts, but I haven't seen it.
Ton ton
Well-known member
I use my 11 mm wrench on a semi- regular basis.
Shoreline_
Well-known member
Pretty sure 9 is 11/32 and 11 is 7/16.
Ton ton
Well-known member
I run into this phenomenon on a regular basis.
Knew about the 11mm but not the 9mm interchangeability. Will have to check on that as I have a stash of those small motor nuts and bolts. Thanks!
I have restored a few British cars from the immediate post-war period. It was common to find Metric SAE and BSW fasteners on the same vehicle, and some times mixed thread/head combinations. The way I understand it things were in such incredible short supply and UK so desperately needed export sales they would use ANYTHING they could lay their hands on.
You need a completely filled tool box to go anywhere near the full range of what is out there.
You need a completely filled tool box to go anywhere near the full range of what is out there.
ronkz650
Well-known member
Handy metric and SAE comparison chart you can download and print free at Tekton. 5.5mm,8mm,16mm,19mm among others are all metric sizes already covered by a SAE set.
www.tekton.com
Conversion Chart Card (5 x 10 in.) | TEKTON | APG40001
Made of synthetic paper that is waterproof, tearproof, resistant to chemicals and grease, and won't curl. Chart covers sizes 0 - 2 in. and 0 - 51 mm.
joel63
Well-known member
Bubba Fett
Well-known member
These days, I'd say you need a no-skip metric set, and then a set of common fractional sizes, unless you work on a lot of older stuff, or you have socket holder and must fill in the empties.
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Meh. I own nothing in 3/4" drive and have had a 36mm BMW oil filter socket for decades. I mean you can find them for less than a tenner delivered to your door. Same as any oil filter strap wrench, plier, or cup, if you DIY, you're going to need something. Plus, one can torque the filter cap correctly with 3/8" drive.
Dave455
Well-known member
In the immediate post war period (late 40’s early 50’s) while there was still food rationing, mechanical parts were not generally in short supply - the reason being that the country still pretty much had a war economy, and was turning out substantial quantities.
In fact, there was a degree of over production, as witnessed by the vast quantities of parts from this era that were subsequently sold as surplus!
Most of the items produced in this period were of the highest quality - everything from hand tools and machine tools, through to railway locomotives and aircraft.
What did happen, was a switch from British Standard fasteners to Unified. In theory, anything first produced after 1958 should be Unified, but there are many things first produced before that date that continued to be produced using BS fasteners, but incorporating components using Unified.
If in doubt, look for the “Unified” symbol of three interlocking rings - as shown on this aircraft vertical speed indicator.
Metric back then was totally unheard of. Unless you were working on “foreign” vehicles, most mechanics wouldn’t even have owned metric tools till at least the 70’s.
Generally, if I find a metric fastener on a vehicle that old it’s a more recent modification - UNLESS it’s a BA screw, which are of course basically metric, even though their dimensions are specified in inches.
Prior to ‘58 you will generally find BA/BSF/BSW. Post ‘58 BA/UNF/UNC. You will not find the Unified “numbered series” on any British road vehicle, but you will find them on aircraft!
Dave455
Well-known member
Yes, you can, but you still need to buy a special tool just to do an oil change!Meh. I own nothing in 3/4" drive and have had a 36mm BMW oil filter socket for decades. I mean you can find them for less than a tenner delivered to your door. Same as any oil filter strap wrench, plier, or cup, if you DIY, you're going to need something. Plus, one can torque the filter cap correctly with 3/8" drive.
rancherbill
Well-known member
Buy a complete set from the start.
My OCD kicks in when I buy another brand to fill in the skips. If my brand does sell the 'skips' to fill in their set they are super expensive.
My OCD kicks in when I buy another brand to fill in the skips. If my brand does sell the 'skips' to fill in their set they are super expensive.
richfinn
Well-known member
I suspect socket manufacturers make sets with sizes that people will actually use and aim them at a particular market region to keep pricing competitive (be it DIN/JIS/SAE or whatever)
I know this doesn't help the guys who want to be equipped for every eventuality but you can always upgrade and buy Snap-On/Ko-ken or other more specialist brands who sell every size.
I think a better question is "why do the socket organiser manufacturers insist on producing racks with sizes nobody actually uses?" (The ones marked with sizes seem to be more popular in the USA)
Of course you could just assemble your own custom rack just for the sockets you really need and not worry about "filler".
I have a mixture of complete (back up sets) and bespoke sets (which I find work better for me, as I decided which sizes to include, I mark the sizes myself with the little stickers from the ernst kits)
I know this doesn't help the guys who want to be equipped for every eventuality but you can always upgrade and buy Snap-On/Ko-ken or other more specialist brands who sell every size.
I think a better question is "why do the socket organiser manufacturers insist on producing racks with sizes nobody actually uses?" (The ones marked with sizes seem to be more popular in the USA)
Of course you could just assemble your own custom rack just for the sockets you really need and not worry about "filler".
I have a mixture of complete (back up sets) and bespoke sets (which I find work better for me, as I decided which sizes to include, I mark the sizes myself with the little stickers from the ernst kits)
Every car I've ever owned or worked on needs a "special tool" to do an oil filter change. Honda, Nissan, Toyota, Jeep, Ford, Chevy, Volvo, Subaru. You make it seem like BMW is a special case
Dave455
Well-known member
Yes, fair comment!Every car I've ever owned or worked on needs a "special tool" to do an oil filter change. Honda, Nissan, Toyota, Jeep, Ford, Chevy, Volvo, Subaru. You make it seem like BMW is a special case
But I grew up with British cars, almost all of which just needed standard tools. Still work on a lot.
With the switch to cartridge oil filters, I acquired a Facom oil filter wrench, (below - superb tool) with a stainless strap that’s able to handle every cartridge filter I’ve ever encountered, which is most British or Euro cars since.
I know that many makers have switched back to separate housings, and special tools, but I don’t see many Chevy’s and Jeeps in my part of the world (and I’m pretty sure the last Suburu I saw had a cartridge filter), so it’s only really BMW’s (and Mini’s) that I find myself needing these big sockets for.
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