Question for weight lifters...

[ffutures]

How accurate are the weights of weight disks? E.g., if one is marked as 1.25kg, what's the margin of error?

They look to be a LOT cheaper than the weights that are usually sold for physics, and the Olympic style ones are a fairly convenient shape, round and flat with a centre hole and a grip cut-out at one edge. They don't seem to sell them in 1kg size, unfortunately, but one supplier is offering 8 x 1.25kg for about £18 plus delivery, which seems pretty good value.

Comments

[nojay.livejournal.com]

You might like to ask on your local Freecycle if you're looking for weight-training weights. There are enough people out there who have such things gathering dust in a cupboard, bought in a flush of enthusiasm and then abandoned in despair as the pounds don't magically melt off by themselves.

The other place to look is Cash Converters. You'd have to pay money, of course but you'd save on shipping.

[ffutures.livejournal.com]

Certainly a possibility. Would the average home set include a lot of the 1.25kg ones?

[nojay.livejournal.com]

I honestly don't know. All you can do is ask, I suppose. Another alternative is if your school has metal workshop classes; a good school project would be to get some plates made up by one of the classes -- given the density of steel, starting from a plate of x mm thickness with a y mm diameter hole through the centre, what should be the outside diameter to make a plate weighing z grammes? Now go make it. Good practical stuff and a useful result.

[ffutures.livejournal.com]

No chance; girl's school, remember, the nearest to metalwork is the "resistant materials" part of the design and technology syllabus, and that barely touches metals apart from fairly thin aluminium and brass sheet. In any case the D&T department is moving at the same time as us, and will probably be in more of a mess and for much longer.

[feorag.livejournal.com]

Argh!

[ffutures.livejournal.com]

The school's expanding, so we may eventually offer metalwork as a separate subject, or some sort of engineering course at A-level, but I doubt it'll be any time soon. It's supply and demand, I'm afraid, and a bit of a chicken and egg thing - it costs vast amounts of money to resource something like metalwork, so nobody does it unless there's a lot of demand, And if the course isn't on offer there's unlikely to be much demand...

Meanwhile D&T does cover quite a lot of manufacturing, CAD-CAM, etc, but mostly with wood and plastics rather than metals.

[trinfaneb.livejournal.com]

I lifted alot of weights when I was high school, but I never thought to weigh them for accuracy. Oh well :)

[raygungothic.livejournal.com]

I doubt they're very accurate but I shall check some this evening if I can. I have four 0.5kg and four 1.25kg ones I don't need, would you like them?