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Bowstring came off a compound bow which was dryfired - best way to fix that?

Okay, so someone recently contacted me for compound bow repairs regarding their Bear compound bow which had been dryfired.

Note - I don't ask WHO dryfired the bow - I will just assume the owner accidentally gave it to a friend who immediately dryfired it before they could warn them not to...


When a compound bow is dryfired it rips the cables / bowstring off of the cams (pulleys) and can even damage the axle(s) which hold the cams. There is also a chance that the limbs and other parts of the bow could also be damaged.

In this case however the axles and various other parts were undamaged, only the bowstring came off.

Therefore this is actually a fairly easy thing to fix.

STEP ONE - MEASURE THE POUNDAGE

Determine the poundage of the bow by measuring the placement of the limbs on the riser. (This way when you reduce the poundage you will be able to return the bow to its original poundage later.) For best results I recommend measuring both top and bottom limbs to make sure they were even in the first place. It is possible that one or both of the limbs have been loosened during the dryfire, so the limbs should really be "reset" anyway to ensure they are a consistent poundage.

Write down the measurements just in case you get distracted and forget.

If the bow was already in good condition and strung, you could use a bow scale to measure the poundage instead, but since it is unstrung and needs to be strung, measuring the position of the limbs/riser is your better bet.

STEP TWO - COUNT THE TURNS

Slowly reduce the poundage of the limbs using an Allen key. Start with the top limb and do 1 full turn. Then the bottom limb and 1 full turn. Repeat the process while counting the number of full turns.

Keep track of the number of full turns it takes to lower the compound bow to its lowest possible poundage setting. Take note if it takes an extra 1/6th, 1/3rd, 1/2, 2/3rds, or 5/6ths of a turn to do this.

Afterwards note down on paper that it took X# of full turns (+ whatever fraction) to reach the lowest point. Knowing this number will be handy when you are later returning the bow to its original poundage and is basically a secondary method of checking that the poundage ends up matching the original poundage.

STEP THREE - RESET THE BOWSTRING ON THE CAMS

You need to wrap the cables/bowstring around the cams correctly - how exactly will sometimes vary on the manufacturer and model. When in doubt, consult photos of the cams of the model in question. If unable to do that you will want to look at how the cam is designed and determine which way the cables / bowstring should be properly attached / wrapped around the cams.

During this you may need to use some physical effort to "string" the bow. This is why you lowered the poundage however, to make the stringing part so much easier. Depending on what the lowest possible setting is this could be really easy or really hard, and thus this process might still require some grunting and physical labour. There are some tricks to doing this however. It is obviously easier to use a bow press, however that can also be unnecessary if you know the other tricks of doing this.

Trick #1. You can lock the cams in place using bolts - like in the image below. This makes attaching the bowstring much easier by placing the pressure on the bolts individually.

Bolts locking the cams in place on a Model T Jennings Compound Bow
Trick #2. In the event you cannot physically get the cams to lock in place, cannot string it for whatever reason, etc - you can just build a homemade bow press.

Homemade Bow Press made of Wood, Chain, Metal
Homemade Bow Press made of Metal

Note To Self - Make a future post about "How to Make a Homemade Bow Press". In the meantime, just go Google that topic as there are plenty of examples online for how to make your own.

Trick #3. A quick and dirty temporary alternative to a bow press is to attach a strong bungee cord to both ends of the bow and clamp it in place so it cannot be accidentally. Then take a metal rod and twist it into the middle of the bungee cord so that it tightens. Keep tightening until it is suitable tight enough for your needs. Then clamp the metal rod in place. Reset the bowstring, unclamp the rod and untwist it gradually, remove the clamps for the bungee cord, remove the bungee cord... and done. It is now strung.

I have never needed to use option #3, but I am listing it for educational purposes.

STEP FOUR - RESET THE POUNDAGE TO ORIGINAL POSITION

Start with the top limb and do one full turn. Then the bottom limb one full turn. Repeat this process until you have completed the full number of turns (+ the fraction if any).

Double-check that the measurement back in Step One is the same. It is? Good. Unless you did something wrong and forgot to do something it should be the same.

Model T Jennings
STEP FIVE - TAKE PHOTOGRAPHS

Honestly, recording what the bow looks like when in its full strung position + desired poundage is just a good habit to get into in my opinion. It is visual record keeping. For me it is an excuse to take photos, write a blog post and record everything. For you, it could end up being handy in the future if you ever need to repair your compound bow a 2nd time.


CONCLUSIONS

So there you go. It is now restrung.

Was it really that hard? No, not really. Helps if you know what you are doing and confident about your knowledge of the topic.

If you need compound bow repairs in Toronto, you know who to contact.

$30 per hour + the cost of parts (if any). Feel free to compare my hourly rate with what other people are charging.

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