Digital scale?

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Chipper
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Digital scale?

Post by Chipper »

Hello,

Can anyone recommend a good, decent digital scale to weigh pinewood derby cars? There are so many out there. Just curious if you get what you pay for. I see some for $9.99 and some $24.99. We have two more years of pinewood and figured we should get one. In the past I had just borrowed one but this year I would like to get one for ourselves. We have a few more months before our derby, but I can tell the fever is getting higher each day!

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Re: Digital scale?

Post by *5 J's* »

I have two of the Triton T2's. Usually you can find them for around $15. I am happy with them.
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Stan Pope
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Re: Digital scale?

Post by Stan Pope »

I have several (5 or 6) of the Harbor Freight "Pocket Scales" (0.01 oz resolution) which often seemed to go on sale in the $10 to $14 range. All continue working well after 3 or 4 years of service.

Biggest issue is the 500 g. calibration weight. Most other scales I have use 200g for calibration. Ended up constructing a second 200g and a 100g weight, measured out on a 0.001oz scale. I've only had one occasion to recalibrate one of the scales when it wanted to report the weight of a 5.000 oz standard as 5.01 oz.
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FatSebastian
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Re: Digital scale?

Post by FatSebastian »

Stan Pope wrote:Biggest issue is the 500 g. calibration weight.
I agree with Stan here. We have several cheap HF scales, and a very expensive MyWeigh scale. The drawbacks with the cheaper scales is that:
  • They have slightly reduced sensitivity (precision) and capacity.
    They may be off by several grams out of the box, and therefore require calibration (in fairness, this may be true of more expensive scales too).
    They do not come with calibration weights, and you may well spend as much or more than the scale on the proper calibration weight purchased separately.
It is helpful to discover the required calibration weight before you purchase. Usually it is equal to the maximum capacity of the scale (but not always).

Overall they are a great value and "must-have" tool IMO, and with gas at $3 / gallon it pays for itself if you ever find yourself driving to the local post office to check your weight.
Last edited by FatSebastian on Wed Jan 12, 2011 3:15 pm, edited 1 time in total.
Chipper
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Re: Digital scale?

Post by Chipper »

Thank you for the information. Over the last few years since I found Derby Talk I know I can count on quick answers to my questions. I appreciate it.

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Re: Digital scale?

Post by rpcarpe »

I use two scales: One old postage scale (.1oz) and a pocket HF job (.01oz).
I use the postage scale for folks to get it close, and the more sensitive one for official weigh-in.

If funds allow, it's really nice to have the same scale(s) at the Pit table and at the Weigh-in table. Prevented some arguments last year at District & Council.
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Re: Digital scale?

Post by dna1990 »

Another vote to buy TWO now. That way they are the same model, version, etc.

We have some older digitial postal models, but this year have two new T2s from MaxV.
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Re: Digital scale?

Post by gpraceman »

Having two scales, especially of the same model, is great. HOWEVER, make sure everyone knows that the Check-in scale is the law! No two scales are exactly alike.

The other thing with scales is to make sure there is some adult supervision around them. We had one scale ruined as a kid tried to see just how high the scale would weigh. He basically overloaded the scale. Some scales have overload protection, but I'm not so sure I would fully trust that feature.
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Re: Digital scale?

Post by *5 J's* »

gpraceman wrote:Having two scales, especially of the same model, is great. HOWEVER, make sure everyone knows that the Check-in scale is the law! No two scales are exactly alike.

The other thing with scales is to make sure there is some adult supervision around them. We had one scale ruined as a kid tried to see just how high the scale would weigh. He basically overloaded the scale. Some scales have overload protection, but I'm not so sure I would fully trust that feature.
Good point Randy - calibrated or not, right or wrong - the Check-in scale is the law!

We make provisions for adjusting weight on all of our cars. Usually a 1/2" hole drilled halfway thought the car the allows the addition/subtraction of some tungsten putty.

I recently built a league car with Pinewood Heavyweights. You can easily "carve" a bit of these Heavyweights off with an sharp knife or x-acto blade if necessary.
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Re: Digital scale?

Post by FatSebastian »

Here is a coupon that expires 9/26/2011 for one of the inexpensive HF scales. $7.99 is the cheapest at which I've ever seen them sell - one could comfortably buy several at this price. (Having two identical scales is useful for gauging the weight distribution on the front and rear wheels.)

Image

This particular model uses a 500 g calibration weight and takes up to a 1 kg load. I would appreciate any feedback regarding this particular model (the ones we have are a slightly older model).
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Stan Pope
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Re: Digital scale?

Post by Stan Pope »

FatSebastian wrote:(Having two identical scales is useful for gauging the weight distribution on the front and rear wheels.)
And good for side-to-side weight distribution measurements! (Either way, make sure that the scale pans are at equal height unless you have an application that utilizes the height difference.)
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sporty
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Re: Digital scale?

Post by sporty »

I bought my 4 scales from e-bay, for around $4.00 each on e-bay and combined shipping, was all under $27.50.


They seem to go in batches, meaning there our deals and then there are great deals you will see, its about takign your time and looking.

For those going even cheaper.


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Re: Digital scale?

Post by cycrunner »

I have two American Weigh scales that I am very pleased with; Current cost at "americanweigh.com" is $14.95. Model AMW- 250. 250 gram capacity and reads to 0.1 gram or 0.01oz. 10 year warranty.
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FatSebastian
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Re: Digital scale?

Post by FatSebastian »

FatSebastian wrote:I would appreciate any feedback regarding this particular model (the ones we have are a slightly older model).
Having a 500 g calibration weight already, I bought one of these scales - the US Balance US-Magnum 1000XR (SKU 97920) to see if it might be preferable to model we already have. It was not. Here is what I didn't like about it:

The clear plastic lid that also serves as a replaceable tray clips on and does not appear to be very durable.

The long side of the tray is too wide to fit under a standard wheelbase. The long side of the tray will accommodate an extended wheelbase, but the CoM will usually be far enough off-center such that the car and tray will tip. If you place a car along the short side of the tray, the car will rest on the display and control panel.

Without the tray, the stainless steel platform is just slightly over 2" wide; two wheels will just barely fit on it, making it clumsy for trying to weigh a single axle. It you rest a flat-bottomed car on the platform, the car will need to have a CoM more than ~3/4" in front of the rear axle line to avoid tipping.

On the plus side, the display is very nicely backlit and the scale is truly pocket sized. The scale I purchased read approximately 1 gram too high out of the box.

Generally then, this scale does not seem well suited for PWD. It would probably be okay if you purchased two and used them with the trays - one for each axle line - to provide a sufficiently wide platform for supporting both wheels. But for that price there are probably more convenient options.
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Stan Pope
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Re: Digital scale?

Post by Stan Pope »

You can make the pan details less important by preparing a 1-1/2" X 3/4" X 6" support to interface between the pan and the car underbody. Zero the scale wtih the support in place, then rest the car on the support with the car and support shifted to place the CM over the center of the scale.

I made some from 1X pine, then routed the sides and top to 1/16" thick to reduce the amount of shift needed to zero the scale.
Stan
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