Crossbow Nation banner
1 - 20 of 31 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter · #1 ·
After shooting about 50 arrows, the last 30 of which have the matching green color nock as the scuff mark, the Flight Groove(*) in the Barrel of my new Barnett TS370 shows what I will call a wear or scuff mark on one side. The other side of the groove shows just a very slight mark. The arrow also shows a wear mark to match the mark on the groove.

[I was planning to insert two images, but I do not know how to do it. I thought I could just select the images from a folder on my computer, but maybe that is not the case?]

Since I am new to the world of crossbows, I have no idea whether this wear mark is normal, or perhaps a problem that needs attention. I the latter, what can I do to remedy the problem?

Otherwise, the crossbow functions rather satisfactorily; as far as I can tell, that is.

Thank you for your help!
Alex

(*) I am not sure of the crossbow terminology
 

·
Registered
Joined
·
8,192 Posts
AlexanderM: If you have the pictures you wish to submit saved under pictures on your computer:
At the bottom when submitting a post, you will see "Upload File". Click on this, then select where your pictures are and select the picture. Click "open". This will put the picture below your post where you click on it as "Thumbnail". This now installs the picture in your post. When you have reviewed everything, then click on "Post Reply". Once this is done any member can read your post and when clicking on the thumbnail, it will enlarge for better viewing.

All the best.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #5 ·
Bunny Rabbit - Thank You!
These are the pictures:
Bow and arrow Bow Compound bow Crossbow Archery

Vehicle door Automotive exterior Bumper Vehicle Auto part


Compound bow Rim Bicycle tire Wire Bolt cutter


I was going to edit my original post and add the pictures to it, but did not see an 'Edit' button.

And now to learn how to time the cams... I looked at several YouTube videos on the subject, but they were not specific on how to actually do it

Thanks again!
Alex
 

·
Registered
Joined
·
8,192 Posts
Checking cam timing will require access to a crossbow press. In the uncocked position, look down from above where a cable crosses the cam. Look at the other cam. If the cams are in time, these reference points should match. To make a correction, the crossbow has to be put in a press and the cam that is behind will need to be advanced a bit by adding 1/2 or full twists to the single loop end of the cable.

A few other things that can cause wear marks in the nock and if not corrected will carry on into the carbon arrow shaft.
1)the nock groove is not 90 degrees to the cock vane.

2}too much downward bowstring pressure, puts extra pressure on the nock. Some Barnett crossbows, the bow string does not center properly in the nock when the crossbow is cocked. Originally it was suspected that the arrow groove was not quite wide enough to allow the arrow to sit a bit lower.

With the crossbow in the uncocked position, look from one cam to the other along the bowstring. If the bow string humps up as it crosses the rail-stock, there is too much downward pressure on the bow string. I have added two shims, one on each side at the top where the riser meets the tail-stock. This has tilted the cam end of the limbs up a bit reducing this downward pressure. Properly set up, one may have the serving of the bowstring just lightly touching the rail-stock or a thin gap between.

3)a cock vane that is a shade too high may try and push the arrow toward one side.

Note: on editing a post: one has up to 10 minutes providing no one has replied to it. Sometimes, I have ran out of time and a warning comes up, so I just start a new post.

From your picture where the green is going all the way to the uncocked position, I would check the cam timing first. Nock wear with too much downward pressure on the bow string will show on the nock and possibly up into the arrow shaft.

All the best.
 

·
Banned
Joined
·
5,838 Posts
If it’s extruded aluminum, there may be a rough edge on that side of the rail too. I’ve had a couple of Excalibur bows that did the exact same thing! There’s no timing on a recurve bow. Some really fine sand paper took care of the rail ruining arrows and nocks! Good luck!


Sent from my iPhone X using Tapatalk
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #8 ·
Bunny Rabbit -
I believe the arrows are OK because the two that were included with the TS370, as well as the six new ones, all exhibit the same wear pattern. I had not noticed the original two arrows because they did not leave such an obvious tell-tale as the green-nock arrows.

To my untrained eyes, and if I am looking at the correct area, the cables appear to be OK.
Iron Horse tack Bridle Metal Eyewear


However, I noticed that there is a difference if I look at a portion of the cam with respect to the limbs. Difficult to explain, so please refer to the pictures, below.

If I hold a straight edge through the cam in these spots, the right cam contacts the straight edge and keeps it away from the limbs about 1/64". On the left cam, however, the straight edge contacts the limbs while the cam portion is 1/64" shy from contacting the straight edge.

Spoke Wheel Bumper Tire Rim


If the cams indeed are out-of-timing, is it at all possible to correct (time) them without a press? During my search for how to check and time the cams, I believe I saw a video that alluded to the use of a screwdriver or similar tool to keep the cams from turning after the string was partially drawn.

Thank you so much for your help!

Alex
 

·
Registered
Joined
·
8,192 Posts
If you compare the bottom cam hole in the first picture and the top cam hole of the second picture the, the top cam appears to be rotated clockwise more as the cable (center cable) covers part of the opening.

To make the correction:
1)add 1/2 or full twists to the single loop end of the cable that goes onto the cam in the second picture or
2)remove 1/2 or full twists out of the single loop end of the cable that goes on to the cam in the first picture.
Personally I would go (1) as this will advance the cam counter clockwise which will increase the speed a bit.

Record any changes, then if something did not work out, one could go back.

Once the cams are timed, mark each cam where a cable crosses with a permanent marker or whiteout to be used as a quick reference when checking timing when ever the crossbow is shot. If a cable or bow string stretched, glancing at these marks would let one know.

Note: when I mention clockwise and counter clockwise, I am facing the bow string as the crossbow would be held in the normal shooting position.

As for using the screw driver or something similar, people have got away with this on some crossbows, but if something goes wrong, the bow and possibly who ever is working on the bow or some one near by can be seriously hurt.

The crossbow would have to be partially cocked and a padded screw driver or dowel inserted in each cam to keep it locked in position against a limb while the cable adjustment is made. If you choose to do this and the crossbow gets damaged, there is no warranty.

Wishing you all the best with what ever you decide.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #11 ·
Here is an update to Post #9:
Blocking the cams will only work when changing out or adjusting a bow string, not for cables. Blocking the cams keeps tension on the cables.

All the best.
I went back to look at the video to which I referred earlier, and yes, it was for replacing the bow string, as you correctly just pointed out. Now I need to find someone or some place that has a bow press - or perhaps build one myself.

Thanks!
Alex
 

·
Registered
Excalibur Vortex 330, Centerpoint Sniper 370, Centerpoint Patriot 425
Joined
·
16,877 Posts
As I stated before on another thread....you can also use a ratchet strap by placing the hooks in the cams on the inside closest points of the cams and ratchet it down until the string AND cables are loosened. I did this to my Sniper to replace the string and the cables were just as loose. I didn't take any pictures at that time but it's pretty simple. Hook it up and put a little pressure on it. You'll see it's safe and easy.;):)
 
  • Like
Reactions: Ron G.

·
Registered
Joined
·
8,192 Posts
Here is a picture of what "Gabowman" is referring to using the ratchet strap in Post #12. I did a temporary set up for the picture only as I use my bow press.

If choosing this option, make sure the cam lobe is not under the limb as one will not be able to remove the cable. If this happens, one can remove both "Y" sections of that cable being careful not to add or remove twists to the "Y" and add or remove a full twist to the cable. Removing the loop on the cam one can add or remove a 1/2 twist.
Auto part Vehicle Fictional character Games


All the best.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #16 ·
Once I have the cables loose enough to be removed, whether by the use of a press, or a ratchet-strap, how do I add the 1/2 or full turn that may be required? In other words, should I twist each of the two cables with the loops, or twist only the single cable from which the other two originate?

Thanks!
Alex

PS. Gabowman, BigBowMan, bunnyrabbit: I do appreciate all the ideas, including the ratchet-strap approach, as well as the concern that this approach puts on the cams and axles.
 

·
Registered
Excalibur Vortex 330, Centerpoint Sniper 370, Centerpoint Patriot 425
Joined
·
16,877 Posts
Yea, I did think about the pressure put on the pins and cams. I know this isn't a preferred way to press a bow to remove strings/cables but at the time it was what I had so I did it. I don't believe that I used any more pressure than when actually cocking the crossbow but I may be wrong....especially taking the chance of distorting the cams. I liked this approach much better than sticking a screwdriver thru the cam holes resting the pressure onto the limbs though.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #19 ·
Just remove the single loop end of the cable that goes on to the lobe of the cam and either add or remove 1/2 or full twists to bring the cam into time with the other cam.

All the best.
I had not followed the cable all the way to the 'other end' where the single loop is! Now I know. Thanks!

Gabowman -
I decided to build my own press. I believe I have all the material I need, but instead of a turnbuckle or a ratchet strap, I will use either a threaded rod, or more likely, a bar clamp. I'll post pictures when done.

Thanks!
Alex
 
1 - 20 of 31 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top