Checking cam lean with an arrow
03-16-2010, 08:48 PM
#1
Fork Horn
Thread Starter
Join Date: Nov 2003
Location:
Posts: 201
Checking cam lean with an arrow
Ive seen people take an arrow and lay it on a cam and then run it down the string. I was told this was to check for cam lean.
How do you do this, what specifically are you looking at?
Thanks
WV
How do you do this, what specifically are you looking at?
Thanks
WV
03-17-2010, 07:53 AM
#2
Nontypical Buck
Join Date: Nov 2006
Location: Where the ducks don't come no more
Posts: 4,420
Looking for just that.... cam lean.
This is something that I do very quicky when I'm working on a bow that has a split buss cable.
I take a good straight (often aluminum and full length) arrow and press it to the side of the idler or top cam. What I want to see is the arrow running parralell to the string on both sides. If the idler or cam is leaning one way or the other, some twists in the appropriate side of the buss cable are needed. Its a quick and easy way to minimize limb torque. It is probably one of the most often overlooked tuning tools, and is a direct cause of unexplained poor broadhead flight (shooter error not withstanding).
This is something that I do very quicky when I'm working on a bow that has a split buss cable.
I take a good straight (often aluminum and full length) arrow and press it to the side of the idler or top cam. What I want to see is the arrow running parralell to the string on both sides. If the idler or cam is leaning one way or the other, some twists in the appropriate side of the buss cable are needed. Its a quick and easy way to minimize limb torque. It is probably one of the most often overlooked tuning tools, and is a direct cause of unexplained poor broadhead flight (shooter error not withstanding).
03-17-2010, 07:54 AM
#3
Typical Buck
Join Date: Feb 2003
Location: USA
Posts: 868
On my bows, if I lay the arrow across the top cam it will run parallel to the riser and would point directly at the same edge of the bottom cam.
If you find that when held flat on the cam, that the arrow angles down across the riser or outward then your cams are leaning.
While this procedure works correctly for two cam bows and hybrids, I am not sure that it works correctly for the binary cammed bows like the Bowtechs. I thought I heard that there was a certain amount of cam lean that was built into them.
If you find that when held flat on the cam, that the arrow angles down across the riser or outward then your cams are leaning.
While this procedure works correctly for two cam bows and hybrids, I am not sure that it works correctly for the binary cammed bows like the Bowtechs. I thought I heard that there was a certain amount of cam lean that was built into them.
03-17-2010, 05:54 PM
#5
Nontypical Buck
Join Date: Feb 2003
Location: Middletown PA United States
Posts: 3,625
OK, so now a couple guys have explained what you are looking for. Now I'll go into a little more detail.
You can use this method to check for possible cam lean, which is actually the limb tips being twisted by the cable(s) being pulled to the side by the cable guard/slide.
As Swamp Collie explained you can add or subtract twists to the appropriate yoke of the cable---assuming you have cables with a static yoke. This also only applies to true dual cam bows or the idler wheel on a single cam bow----either with a split static yoked cable.
On a single cam bow there is nothing you can do to straighten out the bottom cam as there is no split yoke to adjust. The same can be said for bows with binary cams.
Bows with a floating yoke, like Hoyt, can be adjusted, but will always recenter themselves when shot because they have what is called a floating yoke. Some will serve the yoke very tightly to make it a static yoke, but the best way is to replace the cables, IMO.
This may not be the most cmplete explanation, and I'm sure some will add to it or correct me if I'm wrong.
You can use this method to check for possible cam lean, which is actually the limb tips being twisted by the cable(s) being pulled to the side by the cable guard/slide.
As Swamp Collie explained you can add or subtract twists to the appropriate yoke of the cable---assuming you have cables with a static yoke. This also only applies to true dual cam bows or the idler wheel on a single cam bow----either with a split static yoked cable.
On a single cam bow there is nothing you can do to straighten out the bottom cam as there is no split yoke to adjust. The same can be said for bows with binary cams.
Bows with a floating yoke, like Hoyt, can be adjusted, but will always recenter themselves when shot because they have what is called a floating yoke. Some will serve the yoke very tightly to make it a static yoke, but the best way is to replace the cables, IMO.
This may not be the most cmplete explanation, and I'm sure some will add to it or correct me if I'm wrong.
03-18-2010, 06:09 AM
#6
Nontypical Buck
Join Date: Nov 2006
Location: Where the ducks don't come no more
Posts: 4,420
On my bows, if I lay the arrow across the top cam it will run parallel to the riser and would point directly at the same edge of the bottom cam.
If you find that when held flat on the cam, that the arrow angles down across the riser or outward then your cams are leaning.
While this procedure works correctly for two cam bows and hybrids, I am not sure that it works correctly for the binary cammed bows like the Bowtechs. I thought I heard that there was a certain amount of cam lean that was built into them.
If you find that when held flat on the cam, that the arrow angles down across the riser or outward then your cams are leaning.
While this procedure works correctly for two cam bows and hybrids, I am not sure that it works correctly for the binary cammed bows like the Bowtechs. I thought I heard that there was a certain amount of cam lean that was built into them.
I don't think I'd say 'built in'... inevitable is probably more like it. Especially the binary's where the cables are all to the riser side of the string... you are going to have lean and there isn't much of anything you can do about it.
The center pivot bows have center track binary's.... where the cables run on either side of the string... this was a huge improvement.
Now, with the flex guard... they are attempting to have even less lean at full draw.... as the cables tighten. Its a great idea really. Anyone who has tooled around on AT has probably seen some of those shoot-through widgets that folks are making for bowtechs. Really clever stuff that works pretty good.
The other issue to think on is that the string track on both a single cam and a hybrid cam isn't perfectly straight up and down the bow. The idler on a single cam is centered, while the string track on the bottom cam is offset left (for a right handed shooter). That means your string is running right to left from top to bottom down the bow.... its only about 1/16" or so... but its doing it.
The Mathews/McPherson Monsters, the BT/Ross Carnivores, Dartons and a couple others I have seen have floating yokes both top and bottom that are designed (much like the floating yoke on a Hoyt) to evenly distribute cam lean. While not really allowing us to adjust it to speak of... it makes the lean exactly the same every time... and thats really what accurate shooting is all about... consistancy.
