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All About Pole Spears & Slings What is it about that traditional method of the early hunter/gatherers under the water? These devices are indeed interesting and effective. |
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11-15-2016, 02:51 AM | #16 |
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Re: My latest build: Big Game Polespear
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11-15-2016, 05:26 AM | #17 |
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Re: My latest build: Big Game Polespear
Gotcha, thanks. Again, with the CNC lathe access I might have a go at designing my own. Just need to make sure it toggles off easily...
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11-22-2016, 11:16 AM | #18 |
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Re: My latest build: Big Game Polespear
If I am not mistaken, I think that Crist uses the Primeline lingo and not the regular spearo one when he talks about band stretch (not saying he is in any way wrong in doing that). So, when he says he stretches 300% he actually stretches by a factor of 4 and not 3, as most people would perhaps think. His table is also from the Primeline calculator, I think, so when that table says 200%, it is what most spearos refer to as 300%.
E.g. from his site: Tip #1 Say, I have a 'grip to butt length' of 12' then Aaron says to divide that by 2 and I will have the total length of my circular band. That is 6' which again is 3' for a single band. 12' of band stretch length divided by a 3' band gives a factor of 4. Just wanted to mention it as it means he runs higher stretches than people in general do on their guns - but maybe everyone does that for polespears? Last edited by Diving Gecko; 11-22-2016 at 12:12 PM. |
11-22-2016, 04:20 PM | #19 | |
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Re: My latest build: Big Game Polespear
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I started making single bands with looped grips and selling them in '06. Never caught on but then again I never marketed it much. A diver in Japan ordered some with a band rest and there it all started. This is the same time I worked with a guy who had surgery on his hand and had a Bahamas spearing trip booked and he didn't want to cancel. We came up with an idea to put a rest on the spear. I've made a number of these over the years.
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11-22-2016, 04:23 PM | #20 | |
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Re: My latest build: Big Game Polespear
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Slack band gives us nothing, why do we calculate this as band stretch? If someone can explain to me why I've been doing this incorrectly. im all ears.
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11-22-2016, 08:09 PM | #21 |
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Re: My latest build: Big Game Polespear
Aaron just counts old school.
Today, when one counts steps to the door, they make a step and count 0, then 1, 2, 3, and so on. Aaron, counts funny calling the 1st step as ONE. My guess is there wasn't a FREE lunch program when he was in school, and his Dad made him work after school on chores. Both counting methods are out there, one needs to pay attention. At the end of the day, the energy stored in the rubber is quantified based on stretch length, not stretch length + static rubber length. This is what lead to the use of % a unit-less number.
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11-23-2016, 09:16 AM | #22 | |
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Re: My latest build: Big Game Polespear
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But yeah, I come across both ways of counting and even in percentages, people do it both ways. What Primeline and ol' man Aaron calls 300%, others would call 400% or stretching by a factor of four. Anyways, I found out I am sissy - I just took a 4' piece of the carbon tube I will be using for my build, some rubber and my new scale and I could only pull about 44 pounds. So, kinda in the medium range according to Aaron. With proper grips on the final spear, I might be able to pull a bit more but no matter what this is good info so I can dial in my bands a bit before I hit the water (I have to get on a plane to spear so the more I can plan ahead and dial in before hand, the better). Also, Aaron mentions that the lighter Japanese styles spears are not really powered up that much in terms of band force. So, that will help me, too. My spear will be made up by three 5/8'' sections 4' long, then one tapered golf club shaft for the front section at 3' plus about 2' for the shaft and slip tip So, in full regalia, I will be looking at a whopping 17' butt to tip! Yup, proper Jap style. It will, likely, only weigh in at about 2.2 pounds - so should fly fast. With the sections I am using, and by having different bands, I can pretty easily take one of the straight sections out and make it a 13' spear still with the tapered front section, which would make it a tad more manoeuvrable. If I will be more on the reef, perhaps it would make sense to not use the tapered, thinner golf club shaft at the front and instead go straight from the sturdier straight 4' sections (with an adapter) onto the shaft. With that setup, I can make it either a sturdier 10' or 14' spear. Mind you, it will never be a spear you'd want to shoot into caves or under ledges. That said, I am considering running some dyneema between the metal couplers on each end of each section (well, at least the front one) so that if one of them snaps, I might still keep my fish and slip-tip. Last edited by Diving Gecko; 11-23-2016 at 09:46 AM. |
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11-23-2016, 08:12 PM | #23 |
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Re: My latest build: Big Game Polespear
Hey, I only have 20 digits and if I cant make those work my math comes out like this. https://www.youtube.com/watch?v=MS2aEfbEi7s
17', thats a long spear. Not to take your thunder away, length will also introduce drag and the longer you go the slower the spear. You have to have a stronger band, and carbon, kevlar or glass in any design with typical polespear diameters will flex with more band strength. You'll have to twist the band to keep the spear from bending and the more you twist it the slower the spear. Your on the right path with going to a larger diameter. You'll like 5/8" more then 3/8" and 1/2". Single bands keeps the band parallel with the pole and this helps with pole flex. If you have a looped band a thumb hook will also help with keeping the band parallel. When using a looped band drawing up the band on the opposite side of where its attached will help with flex as well. I have this little gimmick I made some years back that helps with flex, actually it controls it so you don't have to twist the pole.
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11-24-2016, 07:21 AM | #24 | |
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Re: My latest build: Big Game Polespear
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Yeah, I am thinking single band. Small ID @ 14.5mm, as I have some of that. I'll move over to my own thread as I actually did start one and I can leave Ren's to Ren:-) |
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06-20-2017, 04:43 AM | #25 |
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Re: My latest build: Big Game Polespear
Hi Ren, just an idea: Since you are using alu tubes, you should be able to cut a thread with a hand tap pretty easily. Then buy a corresponding bolt in the same thread size, lop off the head and insert into the non-tapped pole with epoxy. Drill it transversely and pin it. That could possibly do?
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07-09-2017, 02:22 AM | #26 | |
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Re: My latest build: Big Game Polespear
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