Are these scuff marks normal?

Bunny Rabbit - Thank You!
These are the pictures:





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

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.

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.


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.



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

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.

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.

All the best.