DIY breaking strain tester

[Volitan]

Yet again I return from a fishing trip with the knowledge that the best fish (good kingfish, I saw it take the bait) was lost due to a failed knot.

this makes me think that even after 50 years of tying the same small group of knots there’s a lot about them I don’t know. I think where the critical knowledge is missing is the relationship between knot structure and line characteristics.

So I want to make a device for measuring breaking strain.

i used to do this just using a spring balance, but I know now and I knew then that that method isn’t going to deliver the accuracy required.

My question is has anyone made such a device. I have designed one, but it seems overly complicated and will take a long time to build. Maybe if I could see what others have made and what they’ve learnt in the process there might be a simpler way.

Anyone done this ?

cheers

 

[rickmarlin62]

Wouldnt it be easier to just buy better quality line and learn better knots...

[masterfisho7]

17 minutes ago, rickmarlin62 said:

Wouldnt it be easier to just buy better quality line and learn better knots...

Have to agree 

[Volitan]

I think I’ve already done that. 

but knots still break. I’m sure you have both had knots break or leaders fail at least a few times in your fishing careers. And when it happens you’re left wondering did I tie a bad knot, was the leader faulty, or was it simply beyond it’s design strength and something had to give?

look, I know not everyone appreciates my meticulous approach, but with lighter lines required as fishing pressure increases there will always be a boundary where leader strength is at the minimum. This is especially true for us who rarely have the opportunity to get away to less fished places.

im sure I’m not the only person who prefers not to proceed by seat of the pants approach, so I’m interested to hear from others who have gone down this route.

 

[Nolongeramember]

17 minutes ago, Volitan said:

I think I’ve already done that. 

but knots still break. I’m sure you have both had knots break or leaders fail at least a few times in your fishing careers. And when it happens you’re left wondering did I tie a bad knot, was the leader faulty, or was it simply beyond it’s design strength and something had to give?

look, I know not everyone appreciates my meticulous approach, but with lighter lines required as fishing pressure increases there will always be a boundary where leader strength is at the minimum. This is especially true for us who rarely have the opportunity to get away to less fished places.

im sure I’m not the only person who prefers not to proceed by seat of the pants approach, so I’m interested to hear from others who have gone down this route.

 

If you want to properly test and improve your line and knots you need a reliable way to test them. I use a Shimano spring scale that has a marker to show where the result was. 

Nothing wrong with testing knots mate. I reckon I use some of the strongest and reliable knots going (most with my own modifications to them) because I have tested and proved them over and over and compared the results to other knots. 

 

[Volitan]

32 minutes ago, Hateanchors said:

If you want to properly test and improve your line and knots you need a reliable way to test them. I use a Shimano spring scale that has a marker to show where the result was. 

Nothing wrong with testing knots mate. I reckon I use some of the strongest and reliable knots going (most with my own modifications to them) because I have tested and proved them over and over and compared the results to other knots. 

 

Glad someone agrees.

engineering 101 : ‘you can’t improve a process till you learn to measure it’.

leader selection and knot tying are a process.

 

The Shimano balance is interesting.  Im now thinking I may use that as the core of the system, the rest just being just several levers to make things more ergonomic and allow finer measurements. I notice the blue Shimano spring scale is sold in science supply places for use in high school science, so it must have reasonable accuracy.

[Nolongeramember]

1 hour ago, Volitan said:

Glad someone agrees.

engineering 101 : ‘you can’t improve a process till you learn to measure it’.

leader selection and knot tying are a process.

 

The Shimano balance is interesting.  Im now thinking I may use that as the core of the system, the rest just being just several levers to make things more ergonomic and allow finer measurements. I notice the blue Shimano spring scale is sold in science supply places for use in high school science, so it must have reasonable accuracy.

It’s accurate enough for knot testing duties. You can adjust it as well. I put a known weight on like a 10kg dumbbell and adjust so it reads 10kg. 

The main thing is you can compare results with it rather than worry about how accurate  the numbers are your getting. 

[Berleyguts]

I use Pretest line, so I know what it’s going to break at... this way, I’ll know I’ll be within the line class I’m fishing for ANSA. However, this doesn’t assure me of the breaking strain at knots. Years ago at my local tackle store at Hurstville, the shop owner used to demonstrate to me the different lines and knot combos and what they broke at. He had a little machine that he wound out (don’t really know how to describe it). If you have any contacts at ANSA or GFAA clubs, they may be able to show you the machines they use to test for record claims and competition entries.

Edited January 26, 2019 by Berleyguts

[savit]

@Volitan, Have a look at Paulusjustfishing website. A lot of line testing including knots:

https://web.archive.org/web/20160307173149/http://paulusjustfishing.com/4knotstested.htm

If Paulus does not explain somewhere on his website how he is testing breaking strain (equipment/technique etc) - just contact him.

[big Neil]

23 minutes ago, savit said:

@Volitan, Have a look at Paulusjustfishing website. A lot of line testing including knots:

https://web.archive.org/web/20160307173149/http://paulusjustfishing.com/4knotstested.htm

If Paulus does not explain somewhere on his website how he is testing breaking strain (equipment/technique etc) - just contact him.

I just tried to open the link and it wouldn't open. bn

[big Neil]

5 hours ago, Volitan said:

Glad someone agrees.

engineering 101 : ‘you can’t improve a process till you learn to measure it’.

leader selection and knot tying are a process.

 

The Shimano balance is interesting.  Im now thinking I may use that as the core of the system, the rest just being just several levers to make things more ergonomic and allow finer measurements. I notice the blue Shimano spring scale is sold in science supply places for use in high school science, so it must have reasonable accuracy.

I can understand your creative /inventive bent being tweaked here, so I'll be interested in the results which you come up with. Good luck with your design. I hope it ticks most of the boxes for your inquisitive mind. Good luck bn

[savit]

5 minutes ago, big Neil said:

I just tried to open the link and it wouldn't open. bn

BN, The website has been offline for a while.  Therefore the link is from web archive. The link works for me on Chrome - see below screenshot. May be try different browser?

[Nolongeramember]

47 minutes ago, savit said:

@Volitan, Have a look at Paulusjustfishing website. A lot of line testing including knots:

https://web.archive.org/web/20160307173149/http://paulusjustfishing.com/4knotstested.htm

If Paulus does not explain somewhere on his website how he is testing breaking strain (equipment/technique etc) - just contact him.

He uses specialised equipment which you need for accurate line testing. 

For testing knots though, a spring puller is good enough. You mostly want to compare knots to each other so super accurate figures are not needed. 

[Volitan]

 

4 hours ago, Hateanchors said:

He uses specialised equipment which you need for accurate line testing. 

For testing knots though, a spring puller is good enough. You mostly want to compare knots to each other so super accurate figures are not needed. 

Yep, I’m not after a laboratory standard of accuracy.

The link works for me on Safari on IPad.

 

cheers

 

[kingie chaser]

22 hours ago, Volitan said:

this makes me think that even after 50 years of tying the same small group of knots there’s a lot about them I don’t know. 

 

I am of a similar thinking to Rick, so what knots do you have in your repertoire & what types/ breaking strains of lines are 

you using??

Did the knot actually fail in this case or just not heavy enough to pull up a sizable kingfish that may have pulled you onto structure??

[Volitan]

2 hours ago, kingie chaser said:

I am of a similar thinking to Rick, so what knots do you have in your repertoire & what types/ breaking strains of lines are 

you using??

Did the knot actually fail in this case or just not heavy enough to pull up a sizable kingfish that may have pulled you onto structure??

With respect Kingie Chaser, that’s missing the point of the exercise.

The point of this post is not about the here and now. It’s not about the line that I’m currently using, or the knots I’m currently tieing. The point is to raise the whole scenario of line selection and usage above the typical approach of intuition and anecdote and put it on a measured and objective basis.

i realise this approach isn’t the way most people like to approach fishing, but too me it’s obvious if you buy some line and tie some knots in it then how can you be certain you are getting the best out of it unless you have an accurate and repeatable way of measuring it.

‘I reckon’ just doesn’t fly with me.

 

[kingie chaser]

1 hour ago, Volitan said:

With respect Kingie Chaser, that’s missing the point of the exercise.

The point of this post is not about the here and now. It’s not about the line that I’m currently using, or the knots I’m currently tieing. The point is to raise the whole scenario of line selection and usage above the typical approach of intuition and anecdote and put it on a measured and objective basis.

i realise this approach isn’t the way most people like to approach fishing, but too me it’s obvious if you buy some line and tie some knots in it then how can you be certain you are getting the best out of it unless you have an accurate and repeatable way of measuring it.

‘I reckon’ just doesn’t fly with me.

 

No offence @Volitan but I am merely commenting on your statements in the first & second paragraph of your post.

Had you just said you were looking for a line or knot tester then my response would have been somewhat different!

 

Have you looked at this thread which we are discussing the bobbin knot & knot strength?

Like in the youtube vid I posted you could set up a quick scale pull test.

Seems a lot of trouble to me as 95% of lines are already tested so as Rick said if you buy a quality line it comes with a quality assurance & is a rated & tested breaking strain.

If you want to test your knot strength then by all means go nuts with the scale pull test.

Setting up a rig with a scale would be pretty easy by using one of these 

Edited January 27, 2019 by kingie chaser

[Volitan]

Actually, pretesting counts for very little.

the pretest is for a smooth pull on unknotted line. The question is how are lines degraded by being knotted, by being repetitively flexed, by being subjected to shock loads rather then smooth loads etc etc.

Another issue I have is how do you buy ‘quality line’. What constitutes an assurance of quality - is it the price, the hyperactivity of the marketing efforts, the fact that people who are prominent in the sport swear by it?

If you can’t measure it how do you know it has the features of a ‘quality line’. 

And what constitutes quality anyway when standards tests are so divorced from real world experience.

On use of scales. Researching this a bit, I think the ‘scale pull test’ was long ago invalidated as a way of reliably measuring either knot strength or line test. It serves now only as an annoyance to people in the industry doing it properly. Nothing wrong with using the scales as a source of a reliable spring, but a little bit of extra work and money should allow me to build something that eliminates the major issues. I’m not after scientific accuracy. 

cheers

v.

[kingie chaser]

Mate I think youve lost the plot & way over thinking this one!

You dont want 'scientific' accuracy yet dispute the applicability of simple manual testing or pretesting which is what you were eluding to in your original post.

Im out of this one.

Just buy a good quality line, spend some time learning to tie some decent terminal knots & you will lose less fish.

Good luck with your future fishing endeavors 

Edited January 27, 2019 by kingie chaser

[kingfishbig]

I don't see why a spring scale is not sufficiently accurate if yo are just going to test your knots. A number of tests will reduce the error margin. Also if the line keeps breaking away from the knot then you know you have a 100% strength knot.

[DerekD]

Hi Volitan,

To what strength are you thinking of testing? You said you wanted a simple but repeatable means of testing them. Are you talking joiner knot or terminal knot. Are you talking gradual load or impact load.

Can you get your hands on some say 40 or 50mm dowel and fix it in the air somewhere? First issue is that the terminal knot at the non-testing end should not be a failure point. By tying off the non testing end of the line and wrapping it over the dowel a minimum of 4 times (3.5 times according to one of professor Julius Sumner Miller's books) the friction lock on the dowel and lack of knot there ensures it should give you 100% line strength. The 40 or 50mm diameter of the dowel avoids a point load. Bunnings sells some pine dowel but you would probably need to sand it smooth. https://www.bunnings.com.au/porta-43mm-x-1-2m-clear-pine-dowel_p0082335

On the other end of the line get a bucket with sufficient capacity to test the line - say 30 litres. 1 litre is 1kg so you can measure in say 1 to 2kg at a time depending on the container(s) you use. Bunnings has for less than $15 All Set storage buckets going to up to 85 (or 65 or 38) litres complete with rope handles. https://www.bunnings.com.au/all-set-85l-storage-bucket-with-pope-handles_p2583759

At the bucket end you will need some more dowel which you need to connect to the bucket with some heavier cord. Add an eye of some sorts to this dowel which will simulate the eye of hook for terminal testing. If doing joiner knot testing pass the line through the eye and then wrap it the minimum 4 times around the dowel before tying off to ensure the terminal knot isn't the likely failure point. The other variation is to have a loop point in the cord tied to the bucket and put your choice of hook through this loop. This would test your terminal knot genuinely to the hook.

I'd rather knot (pun intended) sketch it out but hopefully this gets you in a workable direction. It should be a pretty cheap and repeatable system.

Regards,

Derek

PS. Make an allowance for weight of bucket and dowel at terminal end. Don't forget the soft landing for when the line breaks and you will probably want a second container to recycle the water in to. The system can be scaled up or down just by varying the materials of construction. When you do it the first time you can carefully mark the levels in the bucket in say 5 litre increments at 3 equally spaced points (120°) around the circumference to verify it is repeatable and thus shortcut the filling process.

Edited January 27, 2019 by DerekD

[browncrab]

17 hours ago, DerekD said:

Hi Volitan,

To what strength are you thinking of testing? You said you wanted a simple but repeatable means of testing them. Are you talking joiner knot or terminal knot. Are you talking gradual load or impact load.

Can you get your hands on some say 40 or 50mm dowel and fix it in the air somewhere? First issue is that the terminal knot at the non-testing end should not be a failure point. By tying off the non testing end of the line and wrapping it over the dowel a minimum of 4 times (3.5 times according to one of professor Julius Sumner Miller's books) the friction lock on the dowel and lack of knot there ensures it should give you 100% line strength. The 40 or 50mm diameter of the dowel avoids a point load. Bunnings sells some pine dowel but you would probably need to sand it smooth. https://www.bunnings.com.au/porta-43mm-x-1-2m-clear-pine-dowel_p0082335

On the other end of the line get a bucket with sufficient capacity to test the line - say 30 litres. 1 litre is 1kg so you can measure in say 1 to 2kg at a time depending on the container(s) you use. Bunnings has for less than $15 All Set storage buckets going to up to 85 (or 65 or 38) litres complete with rope handles. https://www.bunnings.com.au/all-set-85l-storage-bucket-with-pope-handles_p2583759

At the bucket end you will need some more dowel which you need to connect to the bucket with some heavier cord. Add an eye of some sorts to this dowel which will simulate the eye of hook for terminal testing. If doing joiner knot testing pass the line through the eye and then wrap it the minimum 4 times around the dowel before tying off to ensure the terminal knot isn't the likely failure point. The other variation is to have a loop point in the cord tied to the bucket and put your choice of hook through this loop. This would test your terminal knot genuinely to the hook.

I'd rather knot (pun intended) sketch it out but hopefully this gets you in a workable direction. It should be a pretty cheap and repeatable system.

Regards,

Derek

PS. Make an allowance for weight of bucket and dowel at terminal end. Don't forget the soft landing for when the line breaks and you will probably want a second container to recycle the water in to. The system can be scaled up or down just by varying the materials of construction. When you do it the first time you can carefully mark the levels in the bucket in say 5 litre increments at 3 equally spaced points (120°) around the circumference to verify it is repeatable and thus shortcut the filling process.

I have used this exact method for testing nearly every knot known. Uni knot has never failed for me personally. For joining braid to mono fg has never broke on me but has slipped due to my incompetence. Nearly every other knot i have tested the knot will break before the line does.

[PaddyT]

do you bother to check your drag setting with scales- also a photo of the knot failure would be good to see- might be something different to what you think- testing knots at home is like chasing unicorns- would much rather tie a consistant 70% knot (say for example im fishing kings with 40lb braid (which tends to break at 60lb+ anyway) and 80 lb leader) so my drag is at a measured 7kg (which is more than most people can handle without a harness after 10 minutes), if I have a failure its going to be because the king scrubs me off on the bottom or ive tied a crap knot- which doesnt happen cause I dont stuff around at sea with FG's etc- just go fishing instead- much more productive use of your time

[Volitan]

On 1/27/2019 at 2:34 PM, kingfishbig said:

I don't see why a spring scale is not sufficiently accurate if yo are just going to test your knots. A number of tests will reduce the error margin. Also if the line keeps breaking away from the knot then you know you have a 100% strength knot.

See my comments below about the finnickyness of springs, but multiply it by several times because you’re dealing with a small, very high tensile spring of short travel.

[Volitan]

Hi Derek. Your suggestion is a good one, and I was going to do something similar but using sand not water. In the end I figured building a spring focused device would offer shorter intervals between tests. Probably your method would be a little more accurate because it eliminates the vagaries of the spring which really come to the fore when you start working with them.

Besides, I just like making things.

 

i also note your suggestion of using large dowels for securing the ends without knots. That’s a good suggestion and I understand they are called ‘bollards’ in the testing industry. Like giant stainless steel cotton reels, apparently.

cheers