SAE to metric conversion?

[Mjolinor]

Without the gut you can make huge mistakes.

10 lb feet << that anyone over 30 can visualise. Metric torques I cannot at all. I can use the numbers but that is where the factor of 10 error can do so much. The very first time I did the head on a Jap bike I snapped the studs with exactly that mistake. Had it been quoted in lb ft my brain would have stopped me.

[peter]

1000 feet, 100 feet, 10 feet 1 feet are also factors of 10.
If the distance is 100 miles instead of 10, it's a long walk.

[Mjolinor]

1000 feet, 100 feet, 10 feet 1 feet are also factors of 10.
If the distance is 100 miles instead of 10, it's a long walk.

And that is why we have yards, fathoms, chains and furlongs. A reference distance suitable for each measurement.

[windmill john]

The very first time I did the head on a Jap bike I snapped the studs with exactly that mistake. Had it been quoted in lb ft my brain would have stopped me.

There’s only one person to blame for this, but data protection prevents me from naming him

[Mjolinor]

The very first time I did the head on a Jap bike I snapped the studs with exactly that mistake. Had it been quoted in lb ft my brain would have stopped me.

There’s only one person to blame for this, but data protection prevents me from naming him

Ah, you know the guy that typed the workshop manual and put the decimal point in the wrong place then?

[windmill john]

That’s it, blame Mr Haynes as he’s not here to defend himself

Have you noticed that all manuals show the torque settings for finned Airhead exhaust nuts show 160Nm!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[peter]

than there is an other aspect about de decimal devider there is the "," and there is the ".".
Something like 1.000 means a totally different thing as 1,000
But witch is 1000 and wich is 1 depends on where you are and what system you're in.

[Mjolinor]

It gets even worse than that. As someone born in 1955 my schooling used the "long scale" numbering system then in 1974 the UK decided to go with the Yanker version of numbers where one billion was no longer 10^12 but reduced to 10^9.

My brain still works in long scale and I have to consciously convert to short scale and use the term a thousand million instead of a billion to prevent confusion.

I suppose we should be thankful that we do not use the lahk, crore and arab. The first time I met those numbers I was well noodle baked until I got the hang of it.

[peter]

Luckily I grew up in the SI-system. We didn' even learn how to use a calculation-ruler although calculaters were banned until the secondary school where you needed to calculate sinus cosinus and tangents.

[Rob Frankhamr]

A while ago now, I found my old school book of log tables (which included sines, cosines, secants, cosecants, tangents and cotangents).One little book and I didn't need a calculator.

Rob

[wulfrun]

A while ago now, I found my old school book of log tables (which included sines, cosines, secants, cosecants, tangents and cotangents).One little book and I didn't need a calculator.

Rob

I still have mine somewhere. My mum was a maths teacher and in a bit of one-upmanship, I was the only one to have FIVE-figure log-tables. Everyone else had the "common" four-figure. By the time I got to A-level, calculators were around but too expensive for most so they weren't allowed, slide-rules were but you had to put "(by SR)" beside your calculation results. In college, you could use your own calculator in exams unless it was a programmable one. If you didn't own one, the college would loan you one for the exam.

Despite being only a year youger than mjolinor I'm very glad I didn't have to endure imperial measurements. I'm pretty good at maths but slower than many so it'd have ruined my chances.

[Mjolinor]

I can't remember what years these things happened but for sure up to 1970 the micrometers in metalwork were Imperial as were all the machines.

I do remember being introduced to CGS and shortly after that to SI but I cannot remember when that was. I would guess some time around 1968 or so.

[r75boxer]

I recall in the early 70s when my older brother bought his first calculator. It was a Texas Instrument unit that was able to do square roots. Wow! It cost nearly $30 CDN which in todays dollars in nearly $200!

Kevin

[george baker]

Hi
I'm sure I remember cgs was replaced by MKs before we got to SI.

I had 7 figure log tables but used 4 cos they were faster and slide rules

The school had one calculator in 1970,as big as a typewriter and iirc nick tubes

G

[Mjolinor]

Hi
I'm sure I remember cgs was replaced by MKs before we got to SI.

G

You are right, I had forgotten that. Old git.

[Rob Frankhamr]

In, I guess it must have been 1971, I went to work for an Insurance Company (which I hated) which had a COMPUTER.

All of the new employess were taken to see the COMPUTER which was going to do all of the arithmatic work for us. It was housed in a building the size of a small block of flats and we had to put on smocks, overshoes and facemasks before we went in to the 'computer room'! The highlight of the visit was the 'WINCHESTER DISK' (read hard drive) A cabinet the size of a commercial washing machine, which would or so we were proudly informed, hold 8 million bytes of data... (not that any of us had any idea what a byte was). Input was via punch cards but I do remember there was one green screen for the supervisor.

Output was by reams and reams of fanfold paper. Perhaps the most amusing thing for us 'soft machines' was that, for the whole time I was with the company (approx 4 to 5 years). It never actually worked... but that's progress!

Rob

[windmill john]

The highlight of the visit was the 'WINCHESTER DISK' (read hard drive) A cabinet the size of a commercial washing machine, which would or so we were proudly informed, hold 8 million bytes of data... (not that any of us had any idea what a byte was).

Rob

Cor, 8 meg to play with... luxury

I remember my brother gave me his cast off PC... something... can’t recall.

To get games to run in the 640K limit, you needed to start dos, move everything to upper memory and re-run DOS. Can’t even recall the commands now... hi-umb etc

[DEEP DIVER]

The highlight of the visit was the 'WINCHESTER DISK' (read hard drive) A cabinet the size of a commercial washing machine, which would or so we were proudly informed, hold 8 million bytes of data... (not that any of us had any idea what a byte was).

Rob

Cor, 8 meg to play with... luxury

I remember my brother gave me his cast off PC... something... can’t recall.

To get games to run in the 640K limit, you needed to start dos, move everything to upper memory and re-run DOS. Can’t even recall the commands now... hi-umb etc

My first proper one was a Olivetti SX25 with 170 mb hard drive. But has a Sinclair zx before that.

[wulfrun]

Crikey, your'e going back some way. When I was at college, they had a mainframe that still had core-stores, which are tiny magnetic toroids threaded onto a grid of wires. I think they were 1k (or maybe less) memory each, not sure how many there were but racks of them. Nice thing about them, they are non-volatile memory. The computer was in a whole block, tended to by the revered team of techinician-gods. It was exactly like the computers seen in old-school Sci-Fi films, with panels of flashing lights.

My first computer was a Sinclair ZX81, which I still have and it still works (with self-made 32K memory). I also still have my (also still working) first calculator, a Sinclair Scientific that cost me (IIRC) £25 in 1975.

[Rob Frankhamr]

Crikey, your'e going back some way. When I was at college, they had a mainframe that still had core-stores, which are tiny magnetic toroids threaded onto a grid of wires. I think they were 1k (or maybe less) memory each, not sure how many there were but racks of them. Nice thing about them, they are non-volatile memory. The computer was in a whole block, tended to by the revered team of techinician-gods. It was exactly like the computers seen in old-school Sci-Fi films, with panels of flashing lights.

My first computer was a Sinclair ZX81, which I still have and it still works (with self-made 32K memory). I also still have my (also still working) first calculator, a Sinclair Scientific that cost me (IIRC) £25 in 1975.

Good old Uncle Clive... I started out with his 'build it yourself' Hi Fi system, then it was the black calculator followed by the white scientific one and the 'Black Watch' My first computer was a ZX81 before veering off into Memotech and PCs. Now, for fun, I sometimes run a ZX81 emulation on a PC... trying to remember the keystrokes is great fun...

Rob

[Mjolinor]

Ah. Back page of Practical electronics, lusting after "Henry's radios" offerings, audio amplifier from the Sinclair page inside. A massive 20 watts in a package that fit in a tobacco tin. :)

[windmill john]

Someone at work had a Bluetooth Jambox. I couldn’t justify buying one so I thought I’d make one.

So what set out to be a cheap Bluetooth speaker, ended up costing me £100!
Superb quality sound, but absolute crappy bass. I had read about size of woofer magnet to cabinet depth etc and it is solid wood. I’ve added/removed sound deadening material, added the additional holes. I just put up with it now.

8DA9F502-3BA0-4856-9F0C-85224A6D9498.jpeg

[vmx1200]

The only thing in favour of Metric is that it is universally used in the civilised world.

Interestingly my mate has just retired from about 40 years as an aircraft maintenance engineer for British Airways and he measures everything in imperial as that what Boeing use on their planes.

No I am not going to be drawn on the topic of if Boeing are manufactured in the civilised world

[wulfrun]

Good old Uncle Clive... I started out with his 'build it yourself' Hi Fi system, then it was the black calculator followed by the white scientific one and the 'Black Watch' My first computer was a ZX81 before veering off into Memotech and PCs. Now, for fun, I sometimes run a ZX81 emulation on a PC... trying to remember the keystrokes is great fun...

Rob

I bet you wish you still had the "black watch", unless you haven't seen what they fetch nowadays. Did yours actually work? I believe most didn't. The only Sinclair I built from a kit was the Micromatic radio. Most of Sinclair's designs were actually very good, technically - often ingeniously so. Then usually let down by cheapest-sourced components, cheap, flimsy cases and cost-cutting on things like heatsinks. The ZX81's "slow-mode" performance can be boosted by about 15% by adding one transistor and a couple of resistors that the bean-counters removed. Mine has a sensibly-sized heatsink fitted on the regulator and (so far) the over-utilised ULA chip has held out too.

EDIT: just popped into my head that electronic stuff tends to be based on imperial sizes (e.g. 0.1" pin spacings on DIL chips)

[barryh]

My first Sinclair product in 1970 was the stereo 60 amplifier bought as pre-amp, power amps and power supply modules which I built into a case. Turntable and speakers were built from kits too. It was a step up from an old Dansette style record player.