Instructables

How to make a gram scale using office supplies

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For all of us out there that just needs to measure their rocket fuel right now and can't wait. Or if you're like me who can't imagine spending money on a sale you won't use 99.9999% of the time. Here is how you can build one using your MacGyver skills and ordinary office supplies.
 
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Step 1: Parts List

Binder
Ruler
2 sheets of paper
stapler
paperclip
string
tape
2 large books
coins

Step 2: Fulcrum

Wrap the spring around your ruler 3 times. Measure out an extra 5 cm (2 inches) then cut. If you have nylon string, be sure to heat the ends so they don't fray.
Tie the too ends together to make a loop,
Center this loop at the middle of the ruler.

This point will be your fulcrum,
If you hold the string the ruler should balance and sit horizontal.
The reason you wrap the string is to keep the ruler from slipping out when it tilts.

Step 3: Building your stand

Partially open the binder and sit it on the desk standing up.

Bend out the paper clip, and clip it on to the top of the binder
With the paper clip bent out it should make a nice hook to attach items too.
Now hook the string onto the binder. Mess with the string until the ruler wants to be horizontal when it stops moving. (In physics we call this a stable equilibrium.)

When you find your sweet spot tape it down.
haunted20973 years ago
oh, and you can find coin weights in wikipedia! (At least for euros)
haunted20973 years ago
That's almost like my idea! I managed to measure weights in 10mg accuracy. I use a transparent ruler and I simply balance it on a triangular ruler (http://www.woodrow.net/oneProduct.asp?productId=38). I simply put the coin on the ruler (the ruler on my construction is horizontal) on one side and the thing I want to weigh on the other, suspended on a thin string from the edge of the office. I measured the accuracy by using the scale to measure the weight of some coins with other coins. I'll sometime make an instructable for mine too, the good thing about mine is that it doesn't use tape(exept for the cointainer of the item to be measured). Well done for your scale too! I wanted to see if someone else thought about it and posted it.
 at least there's a formula for this
XHorntail6 years ago
I like the part about coin weights! Very informative.
zieak7 years ago
Cool idea! The only problem with using packaged food for the known weight is that that should be the weight of the food not including the packaging. If You were to use the ketchup bottle then your weight would be off considerably if it was a glass bottle. It would probably work using a dry good dumped into your matching weight trays though. I'm sure this will come in handy some day!