Page 2 of 2 FirstFirst 12
Results 11 to 20 of 20

Thread: Looking for more vane clearance

  1. #11
    Senior Member elkslayer4x5's Avatar
    Join Date
    Mar 2008
    Location
    Lane County, Oregon
    Posts
    2,787
    Post Thanks / Like

    Default

    Quote Originally Posted by Martinlover View Post
    Don't widen those axles....widen the cables using carbon shaft. Its heaps better and you'll gain speed by eliminating friction between the 2 sets of power cables that tend to rub as they are drawn and released.

    1. Cut two pieces of carbon shaft to use as spacers (with an angle grinder or cutting tool - or a very fine hacksaw). One spacer rod will be shorter than the other to eliminate friction between the two sets of cables.

    2. You will need to determine the location of each spacer before deciding the length required to increase your clearance. VIP: See below). This is critical.

    3. At each end of each spacer cut grooves for the strings to fit into (make sure the grooves are aligned at each end of each spacer rod and avoid gooves deeper than the width of the string.

    I shoot a nitrous cam shoot thru system on a Martin Cougar Elite 4. The 2 inside cables rub against the 2 outside cables (cross over point) as you draw. Add wax to your cables and you substantially reduce speed.

    4. Place the spacers between each set of cables and thread with serving down the centre of the spacer (tie the cables together thru the centre of the rod).

    CAUTION: pOSITION THE spacers intelligently. As you draw, the inside cables will move together in one direction and the outside cables will move in the other direction. And as you draw the crossover point will move up and down so test this out and observe the movement. If you dont place the rods correctly you will end up with the inside cables pulling against the rod on the outside cables at full draw. If you place the rods too close to the cam you risk barely meeting the cable with your cam stop at full draw. If you don't make the inside cable spacer smaller then the outside spacer the 2 sets of cables will still rub.

    It works fantastic!!! And the speed gains are terrific over an unspaced shoot thru system.
    Any chance you have photos of what you're talking about? And what about wear on those cables? Don't they rub on the carbon shaft as they move up and down? Seems like there would need to be some sort of roller for the cable to move against to prevent wear. I am interested in what you're saying, as it seems to be what I was orignally asking about. I have solved my clearance problem by fletching with low profile vanes. However, never too late to learn. Thanks for your input.
    http://eastoutfitter.tripod.com/index.html
    http://www.cascadianbowmen.org/
    Martin 06 Slayer, Nitrous C, shoot thru, 63lb, Quiktune 3000, HAA OL 5519, Beman ICS Hunter
    Martin 06 Slayer, Nitrous C, Shoot thru, 55lb, Quiktune 3000, HHA OL 5519 2X, Easton A/C/C
    Ben Pearson 1968 'Cougar' 62" 45#s @ 28" recurve, parallel shaft POC, Zwickey 'Eskimo' 2 blade

  2. #12
    Martinlover
    Guest

    Default spacing shoot thru cables for vane clearance

    further to my original reply / solution.

    I don't have time to load a pic - I keep my bows on a property in the mountains far from where I live. But I will copy the text from my last message and add in more detail. So let me apologise to you if my descriptions below are repetitive –

    REMEMBER: I am shooting a Nitrous twin Cam (non binary) Cougar4 shoot thru with long elite limbs (ATA 43” – and this will be different in terms of how close the 2 pairs of power cables touch, and where they touch.

    MECHANICS OF SHOOT THROUGH
    You need to understand and observe the cable movement on your bow before you can cut your spacers, and you need to observe where your 2 pairs of power cables crossover and how this crossover point moves up and down as you draw.
    On my bow I have 4 power cables or 2 pairs of cables (apart from the draw string). This would be the same on yours I think.
    One pair of cables rus off CAM1 at one end and are anchored to the limb axles at the other end. Lets call this Pair1. Then there is Pair2. Pair2 runs off the opposite CAM2 and are anchored at the cam axles on the opposite limb. The 2 cables in Pair1 move together, as do those in Pair2. So when you secure a spacer rod between the cables in each pair there is no friction because cables and spacer move together.

    Each pair of cables is rolled onto its respective cam as you draw, pulling the opposite limb. Pair1 moves in one direction. Pair2 in the other direction. But each pairis strung diagonally from inside cam on one limb to the cam axle on the opposite limb. Thus the cable pairs cross-over and one set of cables runs inside the other set where they cross. As you draw and release the drawstring, this cross-over point between Pair1 and pair2 moves up and down. On my bow the cross over point is below the arrow rest when the bow is not drawn. It may be different on your bow.

    Where my cable pairs cross they also rub against each other (without spacers). And they rub throughout the entire draw cycle. Draw your own bow and observe. Maybe your cables do not contact anyway but I’m guessing they do because the cam spacing on each limb is identical on my bow, so where each pair of cables crossover they are bound to contact. Add bow wax to your cables and the friction is massive. So when you space the cable pairs, the outside cables need to be spaced a little more than the inside cables to eliminate the contact at crossover point where the inside pair moves through the outside pair. And WHAMMMO! The speed gain is very noticeable on my correctly spaced shoot through. No Bullshit.

    SIZING AND PLACING THE SPACER RODS
    This is where it gets tricky. Each pair of cables is spaced wider where they anchor at the axle end than at the CAM end. I will refer to the limb side where each pair of cables is rolled onto the cam as the ‘CAM END’. So PAIR1 has a CAM END and PAIR2 has a CAM END. Any spacer rod placed between the strings too close to their CAM END will be squeezed as the strings narrow together and roll onto the cam. This will force the strings apart and may push them off the cam lobes or reduce the contact between these strings and cam stop as the cam rolls over.

    Alternatively you can space Pair1 and pair2 at their axle ends. But this is far less effective and you’ll find when you reach full draw the inside pair will pull against the spacer on the outside pair.

    You will need to find a spot closer to the centre shot point to place each spacer rod but make sure you observe the following:

    1. Ensure the spacers are as far away as practical from the CAM END to avoid excessive squeezing during the draw cycle.

    2. make sure the spacers are placed roughly the same distance from the limbs on each string pair. This is because each spacer will push the cables apart and this actually shortens the cable length by a fraction. This tension changes the stress on the limb to which each cable pair is anchored (axle end). You want this effect to be as minimal and equal as possible so try to position the spacers so they have an equal tension effect on their respective string pairs.

    3. Note that you don’t have to cut the spacers to the nearest millimeter because you can slide them up and down the cables to position them but this adjustment is limited to the operation of point 2 above. As you slide the spacing rods between each string pair this will alter the gap between the cables in each pair.

    4. make sure the string pairs are spaced so that the outside pair is slightly wider than the inside pair to avoid contact at crossover point THROUGHOUT THE DRAW CYCLE. Point 2 above requires you to achieve a very fine difference in the spacer tension so the string pairs must not contact but be as close to contact as possible.

    5. Make sure the spacer above the riser handle moves up and out of your sight window at full draw before you cut it to size. Do this by tying or clipping something to the strings and draw the bow to see where it moves.

    6. You need to start this whole spacing exercise with the top spacer first (the one above the handle), mark and test your spacer point before cutting. Then cut it a little wider than you need, test it and cut it down to the minimum space you need. Allow for clearance from inside string pair as in point 3 above. Then you can move on to placing and cutting a spacer for the lower limb, observing points 1 and 2 above.

    7. Now here’s the worst part. Once you have positioned and serveed the spacers in place, draw the bow and check if the inside cable pair pulls against the spacer between the outside pair. It’s OK if it touches at full draw but not if there is too much tension. This happened to me and it had a big effect on my arrow grouping. I had to reverse the postion of the spacers relative to each other by positioning the spacer for the outside string-pair on the other side of the cross-over point.

  3. #13
    flytier17
    Guest

    Default

    I saturate the crossover point on my cables with Scorpion Venom Polymeric Bowstring Fluid. Picked up 8fps over wax.

  4. #14
    flytier17
    Guest

    Default

    Note to add:

    For this proceedure to be effective, you need to have 1 cable pair BOTH on the inside of the crossover, and 1 pair BOTH on the outside.

  5. #15
    flytier17
    Guest

    Default

    OH, AM I EVER DUMB!!!!!

    I cannot believe I didn't think of this after I read your 1st post about the spreaders.

    Just install the wide axel kit on 1 axel, the one with the cables on the outside of the crossover.the inside cables will be standard, the outside cables will be wider than normal.

    I just performed this on my Slayer. I moved the top cables to the inside pair of loop grooves, and left the outside set on the widest setting. It worked! No crossover contact.

  6. #16
    flytier17
    Guest

    Default

    I just checked my cam timing. It moved slightly out of time. I put a 1/2 twist in the inside cable set, butthis corrected it too much. I moved it back. My cams are still prettymuch in time, though not quite as perfectly as before I moved the cables.

  7. #17
    flytier17
    Guest

    Default

    I will do a speed check as soon as I get to the pro-shop, and will post the results.

  8. #18
    Senior Member elkslayer4x5's Avatar
    Join Date
    Mar 2008
    Location
    Lane County, Oregon
    Posts
    2,787
    Post Thanks / Like

    Default Slower or faster?

    So Alec, what happened? said you where going to check speed when you got back to the shop... Been waiting to hear how much of a speed gain, but I'm guessing there wasn't much of an increase. And how does the bow shoot now? I have the wider axels, just missing spacers, but am sure that I can make some.
    http://eastoutfitter.tripod.com/index.html
    http://www.cascadianbowmen.org/
    Martin 06 Slayer, Nitrous C, shoot thru, 63lb, Quiktune 3000, HAA OL 5519, Beman ICS Hunter
    Martin 06 Slayer, Nitrous C, Shoot thru, 55lb, Quiktune 3000, HHA OL 5519 2X, Easton A/C/C
    Ben Pearson 1968 'Cougar' 62" 45#s @ 28" recurve, parallel shaft POC, Zwickey 'Eskimo' 2 blade

  9. #19
    flytier17
    Guest

    Default

    Haven't gotton to the shop yet. But, my groups are a little higher. Not much, maybe 1/2"?

    I will do a speed check this week, or in 2 weeks. I am going on a canoe trip next week.

  10. #20
    flytier17
    Guest

    Default

    Bow shoots fine. I picked up 1 lb of draw weight because the cables were "shortened" by changing the angle.

    It is now more critical than ever for good form. If your arm is straight, it will tougc the cables even more easily now.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •