Here's some pictures of my simple homemade deflection/spring scale:
First find some plastic, here I found that some trellis netting packaging will work.
Here is the design I ended up going with that so far works the best for weights from 1 gram to 4 grams
Find something to support the scale, a wallet or a book.
Calibrate it to the weight you want to weigh out. In this picture I used one US penny(2.5 grams) and 1 dollar(1 gram) = 3.5 grams calibration. Simply pull the scale out of the support until the scale just touches the flat surface with the calibration weight in it.
Remove the calibration weight and add bud(or whatever you want to weight) on to the scale until the scale just touches the flat surface again.
Here's the bud that was weighed out with the cheap scale on a nice digital scale to test it's accuracy. As you can see it was off by 0.1, and with more practice and improving your technique, accuracy can be even further improved.
This is great for several reasons, you can carry something like this around and not be caught with a scale and bud, as this can get you a serious citation in most states/countries. It's cheap and also doesn't require batteries to function. And it's straight bad ass.
If you need to do 0.5 grams you can either cut a dollar in half to calibrate it, or use a stack of pennies next(but not touching) to the end of the scale tray, if the scale is calibrated to 1 gram and when empty is, lets say, 6 pennies tall, add bud until the tray is at 3 pennies tall.
This method is just as accurate as any manufactured store bought spring scale.
There are also simple ways to make a complex balance scale and is even more accurate, like what I call a tissue box scale or a beer case scale, and is technically a safisticated balance scale. You take a case of beer open the top up nice and clean and cut the doors or top off, trying to keep the case semetrical and balanced. Make sure the case is empty. Get another piece of cardboard from the bottom of another box make sure it's longer than the highth of your beer case and almost as wide. You will be using that card board as the center stand of the balance scale. Prop up the center cardboard stand between 4 beers. Invert the empty beer case and carefully place and balance on the center stand. Using the center stand that should still be visible at the bottom of the scale mark where it's at or remeber a marking on the case, this is your balance reading. Now you can place weight semetrically on the top of the box using US currency... To weight out 0.5 gram with this scale you put the dollar halfway between the center of the box balance point and the edge of the box on one side of the scale, while using the other side to slowly add bud to bring the box to perfect balance again at 0.5 gram.
If you understand the concept of weight scales building and using these methods with accuracy is pretty easy.
