what kind of scale would be good and accurate for bike parts and complete bikes. I was wanting to know the weights of various frames and compare weights of stems, bars, seat clamps, complete bikes, etc. thanks for any suggestions.

For some reason road bike parts are always measured in grams probably because many of them come from foreign sources...I would recommend getting a postal scale that measures grams and possibly has a function to convert to ounces. This way you can measure the minute differences in weights between various small parts. If you are also going to weigh up complete bikes get a used market scale and remove the basket and install some type of "meathook" to suspend the bike/frame from. Sorry Bro, but on this one I don't think you are gonna be happy with a one-size-fits-all scale. I think the digital Ohaus I have only reads to the ounce up to 50#. Good brands are...Ohaus, Toledo, Detecto...there's almost as many brands as there are of old school BMX frames. You can probably pick up something new at a good price on EVILbay not to mention my evil master.

thanks for the info! I guess I need a small parts scale and a seperate one for complete bikes or frames. Walmart sells a hanging digital scale made for fish up to 50 lbs., wonder if it might work for the complete bikes. I'll check out evilbay for the postal type scale or some of the brands you mentioned.

I personally use a Chatillon market scale for weighing high dollar road bikes because it's the number one question I get from Buyers off eBay...how much does it weigh? Come to think of it, it seems less likely that you might field the same question about BMX bikes/frames -but- from a purely restoration standpoint, it may help you figure out what model of frame you have in the absence of stickers (the number one complaint of restorers!). I suggest you compile a database of your findings on every frame you weigh that you have some reasonable certainty who the maker was.
I use an explosion-proof gram scale that costs around $700 for the components...this is way over the top and just happens to be what I have on hand. Stick to the cheaper postal scales and you will be able to take it with you if you go to a show etc.
And, if it breaks on you, YOU won't go postal!