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View Full Version : Serving rubbing on my 08 Bengal cam



hunt123
03-16-2009, 03:25 PM
Anyone have any idea about why my lower serving is rubbing on my cam? It came that way from Martin after they put new limbs on it for me. I'm so new to compound archery that I didn't notice it. But I had our local bow tech looking at it for another reason and he spotted the problem.

He tried a number of different things, primarily moving washers around to try to get string clearance but nothing works. The cam is not crooked. It won't be much longer until the cam's rubbed it clear through and I'll have to get new strings. So I stopped shooting it.

The tech is willing to work on it if someone would tell him what's wrong. He's a big Mathews guy and is one of their test shooters before they bring out a new bow. He works on all brands, but not a lot on Martins so it's got him stumped.

I'd rather not send it back to Martin because it'll take 3 weeks. (one week each way in transit) If someone could tell me what he should look for, it might be an easy fix and I could be shooting again in a few days.

He thought maybe the lower limb might be weak and drawing the bow torques it enough to make the cam rub, but that was just a wild guess after the other stuff didn't work.

flytier17
03-16-2009, 03:46 PM
String or cable? A general desintegration, or one spot particularily? Is the cam showing 3/8-1/2" of groove where the string comes off the cam? (proper rotation) Are you sure it isn't lean? Try perssing the bow and looking for burrs on the cam where the rubbing is. Or any sign of abnormality.

Alec

hunt123
03-16-2009, 06:36 PM
String or cable - I don't know. The bow's over at the shop right now and I'm too "green" to know the difference between them. Sorry to be so ignorant - if the "string" is what your D-loop is on, then it's the cable. It's one spot on the bottom serving that's getting rubbed - an area about 1" long and about 1.5 - 2" up from the bottom of it. When you draw, you can feel it and hear it when you get to that point in the draw cycle. It's almost at the end of the cycle.

Cam lean: It could be but I don't think it is, he checked the top "wheel", it was leaning and he fixed it, so I'm guessing he would have also checked the cam. I'm pretty sure the 3/8 to 1/2" groove is showing. I remember reading about it a while ago and went and checked my bow then.

Burrs: that might be possible. We didn't look for that.

bowgramp59
03-16-2009, 07:54 PM
i had the same thing happen to me on an 07 bengal. it was rubbing the serveing at the draw length mod. took it back to the dealer he put another mod. on the bow never had any more problems.

hunt123
03-17-2009, 04:52 AM
i had the same thing happen to me on an 07 bengal. it was rubbing the serveing at the draw length mod. took it back to the dealer he put another mod. on the bow never had any more problems.
Not sure what you mean. He put a different draw length module on and changed your draw length? Or put another one on with the same draw length?

Coop
03-17-2009, 11:58 AM
Not sure what you mean. He put a different draw length module on and changed your draw length? Or put another one on with the same draw length?

what he's saying, that he got a new mod.(same draw length that was on it) and put the new one on... in other words just replace the one on the bow with a new one... Hope this helped...

Coop

flytier17
03-17-2009, 02:35 PM
String or cable - I don't know. The bow's over at the shop right now and I'm too "green" to know the difference between them. Sorry to be so ignorant - if the "string" is what your D-loop is on, then it's the cable. It's one spot on the bottom serving that's getting rubbed - an area about 1" long and about 1.5 - 2" up from the bottom of it. When you draw, you can feel it and hear it when you get to that point in the draw cycle. It's almost at the end of the cycle.

Cam lean: It could be but I don't think it is, he checked the top "wheel", it was leaning and he fixed it, so I'm guessing he would have also checked the cam. I'm pretty sure the 3/8 to 1/2" groove is showing. I remember reading about it a while ago and went and checked my bow then.

Burrs: that might be possible. We didn't look for that.

OK, that is the cable that is being rubbed then. Not the shooting string.

if the cam is leaning, it is a lot harder to fix than the idler. I can tell you how to check. Lay an arrow on the side of the cam, parallell to the string. See if it runs parallell to the string. it should be aparrent which way it is leanoing, if it is at all. But, if it were leaqn, I'd think the string would be affected too, not just the cable.

If you can hear and feel the cable being rubbed, it could be the sides of the cable trace are dented inwards, and too small for proper guidance of the cable. this is a hard part to get damaged, but it does happen. Maybe look into that too.

Alec

hunt123
03-17-2009, 06:34 PM
If you can hear and feel the cable being rubbed, it could be the sides of the cable trace are dented inwards, and too small for proper guidance of the cable. this is a hard part to get damaged, but it does happen. Maybe look into that too.

I'm really embarrased to be so "green" but I have to ask or I won't learn. Could you explain what the cable trace is? I'm collecting everyone's suggestions and will give them to the bow tech next time I see him.

flytier17
03-17-2009, 07:08 PM
First of all, don't apologise for being green. We all start somewhere. You should have seen me when I first started. For the first year, I considered arrow rests optional and only for target shooters, bowstring fuzz got slicked down with saliva only, releases didn't exist that I knew of, and sights were only for target shooters. My nock point was a dab of silver paint, and I held my face as far away from the string as I could. These guyse here quickly set me right with their knowledge and willingness to share information and help. Now, I hope i can return the favorr to someone. This forum is here to help people at any level of knowledge we can provide for, including beginners.

Secondly; I have to apologise for leading you astray. I mistyped that. It should read "cable track". That is the groove the cable fits into as it is wrapped around the cam. Thats all, nothing fancy. Sorry for the mistype.

Alec

hunt123
03-17-2009, 07:30 PM
First of all, don't apologise for being green. We all start somewhere. You should have seen me when I first started. For the first year, I considered arrow rests optional and only for target shooters, bowstring fuzz got slicked down with saliva only, releases didn't exist that I knew of, and sights were only for target shooters. My nock point was a dab of silver paint, and I held my face as far away from the string as I could. These guyse here quickly set me right with their knowledge and willingness to share information and help. Now, I hope i can return the favorr to someone. This forum is here to help people at any level of knowledge we can provide for, including beginners.

Secondly; I have to apologise for leading you astray. I mistyped that. It should read "cable track". That is the groove the cable fits into as it is wrapped around the cam. Thats all, nothing fancy. Sorry for the mistype.

Alec

Thank you for your kind words. It just feels embarrassing to ask such basic questions in the company of seasoned experts. I belonged to a construction forum for a while and learned a lot there. After a while, I learned enough that I could help others and I enjoyed being able to do that. Perhaps at some point I'll be able to do that here and at other archery forums.

Cable track: that makes sense. I'll look to see if it got dented in. The bow tech was supposed to call Martin about the problem, but I wanted to check on this forum to get as much help as we could.

Once we get it fixed, I'll post the results so someone else can benefit if they run into a similar problem.

flytier17
03-18-2009, 07:48 AM
No problem. Stick around here if you can; become a regular, and you'll hopefully learn a lot. Feel free to answer any questions you feel like you can, and there will be plenty of others to either verify or correct your answers. This is like a discussion if you will. Don't be afraid to ask a question, and have fun and learn.

Like I said, the cable track is hard to damage. If it is bent though, it is most likely on the cam and NOT the module. The modules are plastic, so they would be more likely to break than bend. However, maybe the plastic module has an abrasive crack or something in it.

Let us know how it goes,
Alec

hunt123
03-18-2009, 06:04 PM
The main bow tech called Martin tech support yesterday, they talked for a while and tech support didn't have any more suggestions than what had already been done. They wanted me to send the bow back. I picked it up tonight and the second bow tech noticed that the cam had a sharp edge on it where the cable serving contacted it. You couldn't see it, he just happened to feel the cam in that area.

I wouldn't think the cable serving should contact the side of the cam at all, should be maybe 1/16" away, but it does anyhow. So when I got it home, I got a small, very fine file and smoothed/rounded off the sharp edge. Then I blackened the filed edge with a Sharpie and took it out to test it. Couldn't hear or feel any grinding or bumps when I drew it. All I heard was the sound of the shaft going through my whisker biscuit.

Woo hoo! I think maybe it's fixed.

The thing that makes me uncomfortable is that it's probably still contacting the side of the cam, it's just not getting dug up by the sharpness.

Do the cable servings on other Martin bows slide along and contact the side of the cam as it turns??

Is a small wear section normal on the lower serving? The second bow tech seemed to think it was. He showed me a couple other non-Martin demo bows that were starting to show the same wear.

He said that seems to be common on bows that have the cable slide because the slide is pulled way over to get the cables out of the way of the arrow, which then makes it easy for the cable to contact the side of the cam.

Mathews roller guide is better because it's bent so that it keeps the cable off the cam.

Does anyone else here have that kind of wear on their serving?

flytier17
03-19-2009, 06:45 AM
Soynds like you may have it all sorted out. Good for you.

One more yhing you can test for roughness and sharp edges is run a silk cloth (glasses cleaner cloth works great) over the suspicious area, and try feel it snag. This also works for checking for cracks in limbs.

All bow cables; whether Binary Dual, Binary Hybrid, Trinary, Hybrid, Dual, or Solo, are dragged out of the way of the fletches by a cable guard. They always come off the cam at an angle. This will always lead to some degree of rubbing on the side of the cam. How much is determined by the severity of the angle. Highprofile fletches require more clearence, so the angle is more severe. Thats why you always adjust your cable guard (if you can), to barely clear the fletches. This ensures the gentlest angle possible for the cables coming off the cam, and also minimizes cam lean, and increases bow effeciency.

Small wear will always be aparrent, due to the aforementioned algle of the cable. Good serving on a good quality aftermarket strings will last longer. It will be flattened and shaped to the side of the track it fits in, and maybe a faded colour too. After a lot of shoooting, it may seperate again, but by then, the string should be replaced again too.

You can wax the string to help lessen the wear on the serving too. Put a small amount of bowstring wax in the serving where it is getting worn, and do not rub it in. Let it cover and protect the outside of the serving.

I also reccomend Scorpoin Venom Cam and Serving Lube. This is VERY slippery, and lubrigates the cable and string track to make it easier for the servings of the string and cam to conform and settle in the track. Put it on the servings that contact the cam. DO NOT put it on serving that does not touch the cam. It is very fluid, and the string absorbs a lot. If it goes on the serving off the cam, you will lose a lot of unnecessary speed. I mad ehte mistake on my Slayer, and lost 7fps. I removed it with a bowstring cleaner, and tried again just on the cam, and lost only 1.5fps and had the same amount of protection.

hunt123
03-19-2009, 05:14 PM
Man, that's great information! Thanks. I've got a call in to Martin to see if they either have a replacement cable rod holder or can tell me if there's a way to adjust mine to pull the rod closer to the riser. I shoot Blazers so I don't need much room.

I'm also going to see if anyone here sells that serving lube. It makes sense. Kind of like putting WD40 on metal parts to make them slide together easier.

flytier17
03-19-2009, 06:16 PM
Is your cable rod bent? If so, you can loosen the set screws and rotate it to adjust the amount it pulls the cables away. It should be pointed down, so as to place the apex of the pull of the cables as close to the fletches as possible. This will translate into the lest amount of required pull to sufficiently clear the cables.

With a Dropaway arrow rest, rotating the cock fletch sideways and away from the cable will also make for less pull needed for fletch clearence.

Alec

hunt123
03-20-2009, 01:56 PM
I kind of wish it was bent, then I'd have the option of rotating it. But no, it's perfectly straight. I called Martin and asked if it was adjustable on any of their bows including new ones and they said No. Would be nice if a guy could move it so it was out just enough to clear the fletches, adjustable for different ones.

flytier17
03-20-2009, 05:08 PM
You can probably get a bent one ot the nearest shop for $10 or less.

Alec

hunt123
03-20-2009, 06:34 PM
You can probably get a bent one at the nearest shop for $10 or less.
Really! I'll look into that for sure! How would you get the old one out? Just looking at it on the bow, it looks like it's permanently fastened into the block that mounts to the riser. No set screws that I can see. Seems like the block and rod would have to be replaced as one unit. The block has screws but not the rod.

Got some of that Scorpion Venom Cam & Serving lube today. Haven't put it on yet. Kind of spooked by your earlier post.:) Found this comment on ArcheryTalk: "Lubing the serving where it goes around the cam is very beneficial to a smooth draw. Also lube up the cam bushings as well to keep them from freezing up."

So I just put it on the cable serving and NOT the string serving? Or on both? Just drip it onto the serving where it sits on the cam, then draw the bow a few times or run it all the way down the serving & rub it in?

flytier17
03-22-2009, 11:09 AM
Lube the serving of the string and cable where it will ride on your cam, but not on the serving that will never be on your cam.

You can use SV Cleaner if you don't like the results. It worked for me fine.

Not sure on the cable rod thing; I thought they were setscrews in the sight window side of the riser. Anyone else? What bow are you shooting?

Alec

hunt123
03-22-2009, 07:30 PM
I just now went and checked on those set screws. You're totally correct. There are 2 of them. The front one fastens the rod holder to the riser. The back one also attaches the rod holder but additionally tightens down on the rod. So it's quite possible to swap out the rod. I'll be looking for a bent one. Thank you! :)

bowgramp59
03-22-2009, 07:54 PM
i'm sorry that i did not respond again but i have been away from the computer for a while. when i said we changed the mod. i put the same size mod. back on the bow. the aridginal mod was bad ,it was cutting the serving when i drew the bow, had a sharp edge i guess . we reserved the string never had any more problems.

hunt123
03-23-2009, 05:28 AM
i'm sorry that i did not respond again but i have been away from the computer for a while. when i said we changed the mod. i put the same size mod. back on the bow. the aridginal mod was bad ,it was cutting the serving when i drew the bow, had a sharp edge i guess . we reserved the string never had any more problems.
Thank you for responding. After I inspected my cam/mod I kept wondering how replacing the mod would help the problem. But your sharp edge is the same thing my cam had and smoothing it down solved it. Hope this thread is helpful to someone in the future who might have the same problem.