grain scales

kennyp

New member
Can anyone recommend a decent set of grain scales?. Would like to start making my own arrows and weigh current ones as am changing arrow rest to a trophy taker and the choice of the three blades are arrow weight dependant.

Cheers,
K.P.
 


KidCurry

Active member
Can anyone recommend a decent set of grain scales?. Would like to start making my own arrows and weigh current ones as am changing arrow rest to a trophy taker and the choice of the three blades are arrow weight dependant.

Cheers,
K.P.
Try here ...Digital Pocket Scales 100g x 0.01g MYCO MZ-100: Amazon.co.uk: Kitchen & Home

I've been using this for years. Still on original 3xAAA batteries. Resolution 0.1grain. More than accurate enough for building sub 1grain arrow sets. I put a couple of strips of insulation tape across the platform to stop the arrows/round things rolling off. It will calibrate the sticky tape weight out at start up. Amazing value for money. :)
 


Rik

Supporter
Supporter
0.01g is a little over 0.15 grains, so probably good enough :)
I'm not going to trade in my mechanical balance (good to 0.1 grains), though...
The modern stuff does appear to be cheaper and easier to store, however.
 


kennyp

New member
Also from Amazon, I have had these for a while, they come with two 'lids' that can be inverted to stop stuff rolling off the scales. I took them to our lab and checked them against the lab scales, incredibly accurate and repeatable.

Smart Weigh 500 x 0.01g Digital Pro Pocket Scale with Back-Lit LCD Display: Amazon.co.uk: Health & Personal Care
Geophys, did you have to calibrate them before use? How easy was it?.
these seem to be great for what I am intending using them for and the price is great. The others mentioned worry me because they are so cheap!.....I don't mind buying cheap but sometimes you can buy too cheap and end up buying again.
thanks
 


Geophys

Member
No calibration needed, they have the usual zero button to set the readout to zero with a weight already on them (such as the inverted lid), and they can be set to all the usual weight modes. They seem well made and have proved reliable so far.
 


Del the Cat

Active member
+1 to KidCurry's post. MYCO scales switch between grains and grams et, just the job, cheap enough too.
I dropped one onto a concrete floor and smashed 'em. Just got another set online.
use 'em for weighing out my Resintite glue too (a suspicious looking white powder!)... brilliant.
Recommended as a great investment :)
Del
 


Senlac

Supporter
Supporter
You'll need scales with one decimal place. I.e. scales that show "180 grn" are ok for general use. But to get arrows matched well, you'll need scales that show "180.2 grn". And make sure the zero doesn't drift...
Some digital scales come with a 100gm weight, so you can calibrate them.
However, absolute measurement accuracy is not very important as many scales will expose a difference of a grain or so between arrows. If you're trying to build a set of almost identical arrows, what's much more important is repeatability. I.e. it's not much good having scales that are specified as accurate to 0.1grn if when you measure one arrow several times the weight each time is shown as slightly different. When I was trying to build a set of arrows of identical weights I first measured the weights of the bare shafts, five times. Actual measured weights shown for the same arrow shaft were: 165.7, 165.6, 165.6, 165.4, 165.3, average 165.5grn. Then I did the same for the points, five times. A typical 100grn point was: 99.8, 99.5, 99.8, 99.8, 100, average 99.8grn. Then I tried to match points to shafts to end up with overall weights within a 0.7grn range i.e 0.2%.
 


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If you want to splash out you can get a set of magnetically damped beam balance scales from Lyman but they will cost you a goodly sum. You also have to consider that 0.1 of a grain is a very small weight, 6.4 milligrams or another way 0.0064 grams. Given all of the other variables a cheap set of pocket scales will do you just fine and variations when you weigh things may be down to temperature changes as what you are actually measuring is tiny changes in resistance in an electrical circuit under a load and temp can alter that.
I betch my wooden arrows to the nearest 2 grams when the shafts weigh in the region of 25 grams. Again, the changes in speed or velocity when actually loosing them will make very little difference until you get to 100 yds and all the other variables will make a bigger difference including temperature. How much does your riser change in length between a cold winters day and a hot summers day?
Get the chronograph out and if necessary batch them again. Loose each arrow at least 5 times over the chrono and average the fastest 3 readings to determine each arrow's speed. Ignoring the 2 lowest readings is just normal statistical practice for such tests.
 


GoneBad

Member
Try here ...Digital Pocket Scales 100g x 0.01g MYCO MZ-100: Amazon.co.uk: Kitchen & Home

I've been using this for years. Still on original 3xAAA batteries. Resolution 0.1grain. More than accurate enough for building sub 1grain arrow sets. I put a couple of strips of insulation tape across the platform to stop the arrows/round things rolling off. It will calibrate the sticky tape weight out at start up. Amazing value for money. :)
I use these. Excellent little scales. To weigh arrows I use a 2" length of 40mm plastic drain pipe with a couple of notches in the top. Put the pipe on the scales, zero the reading with the tare button and away you go.
 


Black Sun

New member
Geophys, did you have to calibrate them before use? How easy was it?.
these seem to be great for what I am intending using them for and the price is great. The others mentioned worry me because they are so cheap!.....I don't mind buying cheap but sometimes you can buy too cheap and end up buying again.
thanks
most of the mini digital ones tend to be self calibrating and are usually very easy to calibrate, however it's always worth getting a small set of calibrating weights to check against.

https://www.amazon.co.uk/s/ref=a9_asi_1?rh=i:aps,k:calibration+weights&keywords=calibration+weights&ie=UTF8&qid=1453122887

Calibration weights can get v expensive (depending on how accurate the weight is certified to and how well made they are) but as a general check that your scales are being consistent (which in this instance is the more important factor) they don't have to break the bank.
 


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