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Main Boards => PowWow => Topic started by: Keefer on August 06, 2014, 06:36:00 AM

Title: An overlooked problem with string breakage!
Post by: Keefer on August 06, 2014, 06:36:00 AM
I just read a post of another string break and this isn't a post where you will find the answer "But" a post where one might want to look as to why it broke and how can one keep from having another happen...
I have read every possible solution or reason to why it might have broke and two that really stand out is a crimped on knock that's way too tight or a limb tip that may have a sharp edge somewhere that just might cut into the loops..
That and some folks will put too much super glue on the tie on nocks and form a sharp crystal that acts as a knife cutting the string..
Now these are just some areas to look at first but here's one that many folks may or may not think about and it's the Nock on the arrow...
What I am referring to is a plastic nock or most nocks are formed in a plastic injection mold and if too much 1st stage pressure is put in the mold it cause's a term called "Flash" where the mold will overflow that area where the parts join together and when cured and the part is released from mold an operator is supposed to examine the parts and the seams and look for flash,voids or parts that got short shot and didn't form all the way..If you were to examine a nock very closely inside at the throat or where it snaps on the string look for that seam and make sure you see "No" extra material there...If it has a line of flash or material that could also be a cause as to why a string broke at the serving area..You could fix it by using a small round file to clean it up and still be safe to shoot..
This is not the answer but I never hear of anyone checking for that ..
I used to be a "set up" man and set up mold machines and if we put too much first stage pressure we would overfill the mold and an operator would call to have us fix the problem or trim the part if not too bad...
I have seen molds that made parts in about a 20 second turnaround cycle time and if nocks are made with say 10 molds of nocks to one mold and an operator had to watch several machines I bet a many a part went through unchecked...I've seen it where I worked cause costs were cut and people were overloaded with watching several machines at once..
Please take this as just a possible area to check as well besides all the other reasons a string might fail...
        Keefers <")))><
Title: Re: An overlooked problem with string breakage!
Post by: Mudd on August 06, 2014, 08:34:00 AM
Thank you!
Title: Re: An overlooked problem with string breakage!
Post by: ranger 3 on August 06, 2014, 08:43:00 AM
Great thought
Title: Re: An overlooked problem with string breakage!
Post by: Bjorn on August 06, 2014, 01:16:00 PM
It is the tie on nock and crazy glue combo that is giving me the willies! I have that on all my strings=say it ain't so!   :banghead:    :banghead:    :banghead:
Title: Re: An overlooked problem with string breakage!
Post by: Doc Nock on August 06, 2014, 01:54:00 PM
Look at that...the MD "elf" turns sage and advisor!

Good stuff, Keith.  Not waxing I've been told can lead to fraying and premature wearing...

You used to make your own "secret" formula string wax...of which I still have and use some!

The simple stick and string is NOT devoid of things requiring care and observation.  

Nice contribution, bro!
Title: Re: An overlooked problem with string breakage!
Post by: Keefer on August 06, 2014, 03:47:00 PM
Doc,
I hope you didn't remember my "secret way"of filling those little containers full of wax..It's a Redneck operation that's for sure!   :goldtooth:
Title: Re: An overlooked problem with string breakage!
Post by: Orion on August 06, 2014, 07:48:00 PM
Good info about the nocks, Keefer.  Thanks. I believe I'll start checking mine.
Title: Re: An overlooked problem with string breakage!
Post by: Rufus on August 06, 2014, 09:01:00 PM
Y'all reckon Duco might not be as harsh as superglue? I always use a tad when I tie off my serving and that's what I've used forever when I tied nock sets before I learned the tie for movable ones.
Never a problem.
Hey Doc, R2.    :wavey:
Title: Re: An overlooked problem with string breakage!
Post by: slowbowjoe on August 06, 2014, 09:19:00 PM
My understanding is that thinner glues, whether Duco or liquid Super glue, can seep beyond the serving and weaken strands of string. Whereas the gel form don't penetrate as much.
Keefers input is very good to know, never had a thought about it.
Even a non glued, tied on nock can compromise (and later break) a string, if the material used is thinner than the serving &/or tied too tight (separates the serving and weakens the string. Don't ask how I know!).
All good knowledge here, and caution.
No fun at all having your string beak, to be sure.
Title: Re: An overlooked problem with string breakage!
Post by: LBR on August 06, 2014, 10:41:00 PM
I squeeze my crimp-on nocks HARD--never had a string break.  I think the reason is the quality of nock pliers I use.  They don't just mash the nock set, they round it out.  I don't know that you could squeeze it hard enough to cause a string to break, unless you used a nock set that was way small to begin with.

Also never had a problem with glove/tab wear due to a brass nockset.  Good pliers can save you a lot of hassle.
Title: Re: An overlooked problem with string breakage!
Post by: Dorado on August 06, 2014, 10:52:00 PM
LBR, What pliers are you using. If I'm not very careful with mine they'll put an edge on my nock.
Title: Re: An overlooked problem with string breakage!
Post by: bigbadjon on August 06, 2014, 11:26:00 PM
I don't know what Chad uses but Tru-Fire's nock pliers where the gold standard last I used brass nocks.
Title: Re: An overlooked problem with string breakage!
Post by: iii on August 07, 2014, 07:38:00 AM
There is no realistic way anyone making a reasonable amount of nocks or other similar sized parts could check every unit. Generally tests are made at random intervals in batches, most often the frequency is higher at the beginning of cycles or when more raw material is added to the feed etc.

When they find bad parts one would hope that they would discard/check the batch it is related to, but I would doubt this is something that is done if the damage is not too severe. Depending on raw material the damaged parts could possibly be ground up and remade. But all this costs money.
Title: Re: An overlooked problem with string breakage!
Post by: LBR on August 07, 2014, 11:12:00 AM
John nailed it.  I use the Tru-Fire Pro.
Title: Re: An overlooked problem with string breakage!
Post by: maineac on August 07, 2014, 11:59:00 AM
A good thought.
Title: Re: An overlooked problem with string breakage!
Post by: Keefer on August 07, 2014, 05:26:00 PM
Bo,
You are correct as to not every part can be checked at those cycle times and the plastic department I worked at had a procedure where the operator had to take the parts 4 times per 12 hour shift and document the size and use calipers and mikes etc. when cured with his/her name,badge number etc. so if a batch of parts went to the assembly line they could backtrack the problem if someone cought it there.. Every container had a date code written on it and there was a date/ dial pin on some molds where you had to adjust the date and such on the mold but not many knew it or used it..Even with I.S.O. 9001 parts went through and went out the door with problems and came back...I'm not saying they don't monitor nock's at all cause I'm sure they do the best they can..Then again I had operator's that watched the clock and couldn't wait to get off their shift and let parts go unchecked and just hit the conveyor switch and let small parts go into a plastic bin unchecked..
Usally most problems were solved at start up of setting up a mold and processing everything..
I only made this post for something to consider and to look into as well as all the other reasons some strings might fail not as "the reason"...
It wouldn't hurt to take a few seconds just to look at your nock throats and see if it's smooth with no extra material there that could cause a string to break and damage a $1200.00 bow!   ;)
Title: Re: An overlooked problem with string breakage!
Post by: iii on August 08, 2014, 06:31:00 AM
Agree with the above. Whats called flash could well do the same damage as crystallized superglue under/in the serving.