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| Spearguns & Accessories General Discussion about Spearguns and Accessories in here |
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#1
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Hi all!
Gonna change my Picasso Black Line 100cm head for a open one. And apply it 2 circular 16mm bands. Can anyone get me the formula to calculate the size off the bands? The distance to the first notche it's 92,2cm and 101cm for the second one. Cheers, jmota |
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#2
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1. Take a measure tape and measure the distance from the middle of the
band slot to the center cocking tab. 2. Double the distance ( for both sides of the gun ) 3. Subtract the length of the wish bone. (Alexander and Riffe's are approx 6", Daryl Wong uses about 3".) 4. Divide the number by 3 1/2. 5. This is the length of your powerband if you are using a standard 3 1/2 : 1 stretch ratio. This is a measurement of the powerband from knot to knot. For actual rubber length, add 1" to this length or 1 1/2" in you are tapering the ends of the powerbands. If you have separate holes for each band as with the newer Aimrite/Wong muzzles, then rather than measuring from the center of the band slot (you don't have a slot) to the middle tab, measure from each hole to the appropriate tab, and you will have a different band length for each hole.
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wsbhtr@cox.net |
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#3
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In this case the hole is the same for both bands, can i take the measure for the second band 2cm back from where i take the first measure? ![]() And what is the recommended size for the dyneema wishbone? |
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#4
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With that open slot, the bands will pull back against each other when loaded. Some people would just measure from the rear of the slot to a point half way between the loading fins, but if you want to be anal, measure from the back of the slot to each fin and make two different size bands.
I use 3 mm Spectra (dyneema) for wishbones, but 2 mm will work.
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wsbhtr@cox.net |
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#6
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After all the measuring i'm gonna try one band with 52cm and the other with 57cm, theis for a distance of 93cm and 102cm, and probably a wishbone of 9cm.
What do you guys think? The bands are 16.5mm Omer |
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#7
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I would cut that wishbone down to no longer than 5cm and preferably about 3cm for a eurogun. There is no wood on them to push the bands out of alignment so the dyneema can be shorter
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#8
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I'll do that, thanks Pastor!
I'll tye a dyneema loop to each end of the band and then tye a dyneema cable to the loops, i think it will help to change it if it brakes. |
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#9
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Hi all!
First problem with the bands...i think I've cut it too small...lol For the smallest one and for a distance of 93cm from head to were the wishbone stays, I've cut a 52cm band...and i don't think i cant pull it back...and I'm not a narrow guy, 184 tall and 100kg... For the second one and to a distance of 102cm I've cut 57cm...still not tested... What will be the size of band that you recommend? |