Fluid Measurement - Caveat Emptor

I bought a one litre jug, with extended pouring spout, from a local auto-gear shop with the intent of using it when I change the gearbox oil soon.
So... 420ml. Easy! But... what if?
I checked that to graduations were correct using two methods:
1. With water (1000g/litre)
2. With expensive pyrex glass kitchen jug - No! - No! - I didn't - I didn't! (well, I won't admit to it anyway)
Both showed a 7% error - meaning that, had I used those graduations I would have only put 390ml in.
I did then notice very small print on the bottom saying "approximate volume only"
Dem Bastards!!

And before anyone chimes in with "Just use the level plug!" - it's my preference not to.
If Norton had intended to fill to the level hole they would not have specified "420ml"!

Recently when I used the missus Pyrex jug I had a revelation: the glass is so thick that accuracy is heavily dependant on the angle at which you look at the graduation marks.

This is probably blindingly obvious to most, but was new to me. And is an excellent excuse for my shite cooking / baking !!

Anyway… was your jug Chinese? Reminds me of this:

Always wonder on these Chinese ads that say tolerance is +/- 1 cm on engineered products, obviously not a lot of faith in their products.

I have a cheap plastic 500 ml measuring cup I use. I put 420-ish ml in my trans as measured by the cup - brings it up to the level plug: Calibration Complete!!

When I want an accurate fluid measure, I use a 250 ml graduated cylinder. It even has a pouring notch on the lip.

Slick

I use graduated cylinder as well , came home from water treatment plant lab , store it upside down on rag ….

Use the chinese one on the left for selling, the one on the right for buying.

grandpaul said:

Use the chinese one on the left for selling, the one on the right for buying.

Click to expand...

The one on the right is for your waist line....

I have seen rulers used in the oil drilling industry which are calibrated in feet and 10 ths of a foot.

That one can get you.

Which is a good reason to use metric.

Always bearing in mind the following truth.

johnm said:

I have seen rulers used in the oil drilling industry which are calibrated in feet and 10 ths of a foot.

That one can get you.

Click to expand...

Yes, that is civil engineering / surveying, and will bite you in the butt if you don't catch it!