Small & Big Block Chevies are the reason I own so many standard tools.
SAE vs Metric
- Thread starter Rust_Belt_Pete
- Start date
Small & Big Block Chevies are the reason I own so many standard tools.
By standard do you mean SAE?
I was surprised that every bolt I have touched so far was metric. It is a CUCV 6.2 Diesel
Same reason spark plug threads are metric even going back almost 100 years and the socket size in in SAE. The model T was 1/2" pipe threads.
The first commercially viable plugs and O2 sensors were from Bosch so being European they used metric, the first ratchets were developed in the USA in inch so to keep things compatible between manufacturers these standards were kept.
^^And don't forget the 1/4-20 threaded hole in all the world's cameras.
- Joined
- Sep 1, 2024
- Messages
- 795
USA ratchet makers were the most plentiful in olden days? Although they also fully understood metric. Ratchets are from 1/4 to 1 inch in 5 common sizes. The world gets used to it.
Because WW2 was an apocalyptic event destroying civilized worlds infrastructure. Really the only two places that could make enough stuff to use and export were USSR and USA.
So you bought your tools from the only place that wasnt bombed into dirt which was that weird Yankee dude who dropped 2 canned sunshine's across the sea. Is having a 1/2 attachment weird? Yes but at least he made you some metric sockets while you were busy digging out from the rubble.
Take a caliper and measure 16 vs.5/8,or 19 vs 3/4,you might be surprised how close they are.I'm in the rust belt,I use what fits the best,not concerned with the marking on the tool
Gerald Ford,back in the day,could of got U,S.A on the same page as the rest of the world.Many cars had both Metric and SAE on the same cars.That was a real PIA.
Which is hilarious because the threading is often metric, often 14mm. My Dad had a 1940 Ford flathead that had metric threads tapped for the plugs! That car was so old, it predated the use of Phillips head screws.
I use a 5/16" on 8mm headed fasteners all the time, it fits tighter/ better. Toolmakers and fastener guys deliberately leave a lot of slop in the sizing, too much IMO.
I think your 5/16" experience is just the nature of the manufacturer of your sockets and/or fasteners. Even if both your sockets are the same brand one could have been made on a Friday and one on a Tuesday.
The difference between the two is technically 2.5 thou. Figure the average sheet of paper is 3 thou (you can actually touch off on the side of a square work piece by loosely holding a scrap of paper; when the end mill pulls the paper from your fingers figure you're ~.004" away and set your DRO accordingly) and I have difficulty believing socket or wrench manufacturers are running different tooling for .3125 vs .315"
I strongly suspect all 8mm and 5/16" sockets are the same and just get stamped differently, esp considering all sockets are oversized anyway....who cares if it's 12 thou or 14 thou oversize?
Measuring two Craftsman sockets here in front of me in 3/8" drive, both measure .321" across the flats
I use standard in conversation.
I think the starter bolts, bellhousing bolts and likely the engine stand bolts are SAE on a GM 6.2L Diesel.
Yeah, I am not sure. The starter bolts were 14mm, and the front bolt for the support braket were 12 I Think. Alternator was 15. Weird. Of course, they are all close in the `14\15mm\9/16 world, I generally pick which ever fits tighter.
I am going to change the fuel pump tommorrow.
well, the pump bolts were 7/16
the pump cover bolts were 10mm
another randon braket was 10mm
alternator 15mm
harmonic balancer 15/16
guess i am just screwed
Those are easily convertible to 11mm & 24mm.
On most 80's & 90's GM vehicles....You might need 3/8", 1/2", 9/16" & 11/16" for certain engine/transmission related repairs.
14mm is a little to tight on 9/16" headed fasteners in my opinion, 13mm is to loose on 1/2", & no replacement for a 3/8"
On most 80's & 90's GM vehicles....You might need 3/8", 1/2", 9/16" & 11/16" for certain engine/transmission related repairs.
14mm is a little to tight on 9/16" headed fasteners in my opinion, 13mm is to loose on 1/2", & no replacement for a 3/8"
I am with you.
I generally go with the best fit. I probably dont have near the same selection of tools as you, but I like a tight fit, and 6 point better, so I go by what fits better for the application.
