Introduction of proper terminology. Accuracy: How close the measurement is to the true or accepted value. Precision: How well repeated measures agree with each other. The triple beam device is a balance now a scale. This is not meant to be picky, but if we all use the same terms for the same things there will be less chance for confusion.
Tom -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ed Reeder Sent: Friday, May 28, 2004 5:09 PM To: [EMAIL PROTECTED] Subject: Re: ShopTalk: Electronic Scale? Alan, Thanks!!! I knew I had asked in the right place. After reading all this I'm beginning to wonder if the triple beam balance is the way to go? On a side note, I've got an old, and at the time best, GS beam SW scale. It reads 0 when the pointer is at 0g, but the swingweights don't match Wishon's MOI values, they are about 1 point off and varies by length of club. I'd be willing to guess Wishon's numbers are spot on. (The scale is level front/back and side-to-side, so that isn't the problem). /Ed Alan Brooks wrote: > Be careful. Resolution (or 'Readability') and accuracy are not the same > thing. Resolution is simply the least significant digit in the > readout. Accuracy is how close to 200-g does it read when you put a > 200-g weight on it. There can be a huge difference. If you are buying > it in person, take your 200 (or 205) gram weight with you and try them > out until you find one that reads very close to 200-g. Repeatability is > another issue. Place your weight on the scale and read the weight, take > it off, put it back on and see how close it comes to repeating. Do this > a number of times. Temperature compensation is another potential > problem. Auto-zeroing helps because it takes out an output shift due to > temperature, but you can still have sensitivity errors, i.e. your 200-g > weight will weigh a different amount on a cold day and a warm day. > Check the specifications. Many of these scales are made for kitchen use > and it is assumed that they will be in a nearly constant temperature > environment. > > In any case, after you get the scale, check it regularly with a known > weight, and again when it is warm and cool. Even if the repeatability > is not what you had hoped you can easily develop correction factors. > > Good luck, > > > Alan Brooks > > > At 12:50 PM 5/28/2004 -0700, you wrote: > >> I've been interested in getting a new scale and this one looks >> pretty neat. I'm sure there are some scale experts on the >> forum. (I looked at some triple beam scales, but this looks >> like it serves my needs). >> >> 500g capability, which is all I need >> >> 1/10 gram "readability" which evidentially means accuracy >> according to a few web sites I've seen. I've started playing >> with Wishon's MOI matching stuff and 1/10 gram resolution is >> suggested. >> >> Has a calibration weight, which is huge for me. >> >> Tare (zeroing feature) >> >> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=34088&item=2694364408 >> >> >> Thx, >> >> /Ed > > >
