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Recommendations For A Parts Counting Scale

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Farley:
After searching Amazon I've noticed that parts counting scales range in price from under $50 USD to several hundred dollars.  If anyone has experience with any particular model I'd be interested in hearing opinions or recommendations.

The scale I need will be used for inventory counting of electronic components such as thru-hole resistors/capacitors/etc, probably some SMD parts, and small hardware such as M2-M4 machine screws and similar hardware.

elecman14:
While this is not a recommendation for a specific scale it is a general observation. In my neck of the woods the local scale calibration outfit actually rents scales. They show up a few days before the plant inventory and are calibrated. The bean counters claim that this saves money. You might also want to check with your local calibration outfit (if you ever think you will need to get them calibrated or verified). They may have a scale that is easy to work on. I generally will ask their opinion before buying equipment. It helps build a good working relationship with them and they are happy when they get equipment that they are familiar with or is easy to work on.

SeanB:
While I will not give you any recommendations I will give you a few pointers to look for. First get an idea of the mass of the lightest part, and remember that. Then the heaviest box of that part, and the largest mass box you will be using as a count, along with the mass of a single item.

This gives you now a few things, the lightest item is the limit, the scale resolution must be smaller than this, or you will get count errors which grow as the mass of the item approaches the least significant digit. Ideally you want 5 counts per unit of smallest mass, so you only will have errors in counting packs over 200 parts. That way you can count bags and see easily if they are all correct, at least for bags which are identical in size and mass, and which have the same labels on them. The maximum mass the massmeter can read limits you in the number you can count at a time, and remember that the Tare mass eats away at this limit.

Thus you likely will need at least 2 massmeters, one with a resolution of around 50mg, and probably with a maximum mass capacity of 1kg. That will do small resistors with reasonable accuracy. The second one will probably be a counting scale with 0.5g resolution, and with a 30kg maximum load. This will work for parts like screws and nuts, handling parts larger than M6 (1/4in) up to M20 with ease.

When using the massmeters use metric settings, using ounces will lead to tears in trying to fit the resolution of the massmeters into neat blocks. milligrams are a whole lot easier to use than trying to count where your count starts in grains, then changes to carats, then changes to ounces and quarter ounces then swaps to pounds and ounces, each with it's own rounding errors.

KL27x:

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I've gone through a few different cheap-o electric scales for this type of task. This one is the best-to-date, because the weight is displayed very quickly.

I don't put a lot of faith into a more expensive unit. I think it you drop any of these scales from a significant height, you are going to be out of luck.

Farley:
Thanks to all for the information. I'll probably choose an inexpensive one similar to the one KL27x provided the link for. At that price if it doesn't work out for me it's not a big issue.

I am still interested in hearing of any personal experiences with specific parts counting scales, good or bad.

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