Suggested method for measuring lines
Posted: Fri Sep 20, 2019 8:07 am
Hi All!
In order to get the fly line database off the ground, we need to settle on a standardised way of measuring the lines, and I have had a bit of a think. Let me know what you think (especially you physics-geeks).
Length:
I suspect any length measuring device is precise enough? I have a few different tape measures and when checking them against each other on 2, 5 and 10 meters, they are very similar (maybe half a millimeter to a millimeter off). I realise that temperature is important, but if we agree on measuring indoors every time, at least we can eliminate variation.
Measuring head- and taper lengths is difficult as some are very long, and for instance on a MED, telling the end of the back taper from the beginning of the running line is impossible without precision instruments. Here I suggest that a standard caliper is sufficient, as long as one is aware than compression of the plastic is a issue and only use light pressure. Measure down a taper until you get say 5 uniform readings, and there's a good chance you're on the runningline. Measure back and find where the taper begins. Search for a level tip in the same way.
We can hardly expect people to cut up flylines for this project, so a way of weighing heads is:
Measure out the head length given by the manufacturer. Checking it using the above method would be optimal. As you can put a light downward pressure on the scales through the stiffness of the line, I simply hung in a clothing pin with the mark of the head length on the scale. This also prevents relieving weight by lifting a portion of the line off the scale.
Weight:
I think it's unnecessary for us to use the same scales across the participants, but some form of calibration or check is imperative. I suggest we check out scales (that read at least one decimal) with mint-new coins. I know that for Danish coins and Euros can find official standard weights. A 1-euro coins for instance weighs 7,5 grams. Coins are generally minted to a *very* high standard as weight is one way of exposing counterfeits. Weigh say 5 coins of a known, standard weight and use that to check scales. I've done so with a scale that's unfortunately not mine, but it worked well. 2 one euro coins came in at exactly 15,0 grams. I controlled the reading by zeroing the scale with a small plastic container in which I put 15 cm3 of (fresh)water - luke warm. I use a medical syringe as this was the most accurate weight of getting a precise volume of water. The water also came in at 15,0 grams. For weighing flylines, I think this is precise enough and enough of a calibration.
What do you think? Graeme, James et el., please kill me if I'm way off here - I'm not a physicist, mathematician - just an archaeologist :-).
Lars
In order to get the fly line database off the ground, we need to settle on a standardised way of measuring the lines, and I have had a bit of a think. Let me know what you think (especially you physics-geeks).
Length:
I suspect any length measuring device is precise enough? I have a few different tape measures and when checking them against each other on 2, 5 and 10 meters, they are very similar (maybe half a millimeter to a millimeter off). I realise that temperature is important, but if we agree on measuring indoors every time, at least we can eliminate variation.
Measuring head- and taper lengths is difficult as some are very long, and for instance on a MED, telling the end of the back taper from the beginning of the running line is impossible without precision instruments. Here I suggest that a standard caliper is sufficient, as long as one is aware than compression of the plastic is a issue and only use light pressure. Measure down a taper until you get say 5 uniform readings, and there's a good chance you're on the runningline. Measure back and find where the taper begins. Search for a level tip in the same way.
We can hardly expect people to cut up flylines for this project, so a way of weighing heads is:
Measure out the head length given by the manufacturer. Checking it using the above method would be optimal. As you can put a light downward pressure on the scales through the stiffness of the line, I simply hung in a clothing pin with the mark of the head length on the scale. This also prevents relieving weight by lifting a portion of the line off the scale.
Weight:
I think it's unnecessary for us to use the same scales across the participants, but some form of calibration or check is imperative. I suggest we check out scales (that read at least one decimal) with mint-new coins. I know that for Danish coins and Euros can find official standard weights. A 1-euro coins for instance weighs 7,5 grams. Coins are generally minted to a *very* high standard as weight is one way of exposing counterfeits. Weigh say 5 coins of a known, standard weight and use that to check scales. I've done so with a scale that's unfortunately not mine, but it worked well. 2 one euro coins came in at exactly 15,0 grams. I controlled the reading by zeroing the scale with a small plastic container in which I put 15 cm3 of (fresh)water - luke warm. I use a medical syringe as this was the most accurate weight of getting a precise volume of water. The water also came in at 15,0 grams. For weighing flylines, I think this is precise enough and enough of a calibration.
What do you think? Graeme, James et el., please kill me if I'm way off here - I'm not a physicist, mathematician - just an archaeologist :-).
Lars