Calculating main gear shaft torque from drag settings

[jurelometer]

Jurelometer: I was being serious with my second post, it was a question more then a comment. As far as the torque wrench is concerned it would be one that is calibrated in inch Lbs. Your knowledge in the theory of force applied to the drive gears is beyond my knowledge, and I'm more then happy to admit that. As I said you are supporting knowledge to this site that I can appreciate even though it will never be of much importance to me personally. If my question or comments did offend you I do apologize, they were not meant to at all.   

No offense whatsoever- all in fun.  Rib away!

[johndtuttle]

Anybody looking for a serious upgrade, should consider one of these. Max torque 8450 Nm 

Regards

Mark

Well that would be handy for stump pulling ....

[alantani]

No disrespect intended, but I agree with Dominick.....for once. You guys have to much free time on your hands.You guys need to take into consideration the variables that come to play in force = resistance+Radios< > * distance Etc. Now I'm lost

i've been chuckling at this the whole time!  i have to agree, you guys do have too much time on your hands!   

[Alto Mare]

I actually thought it was very interesting, not for me though, I use old reliable gear,  wagon and bricks . This type of thing would sure help improve some of the new gear available today.
Sal

[jurelometer]

No disrespect intended, but I agree with Dominick.....for once. You guys have to much free time on your hands.You guys need to take into consideration the variables that come to play in force = resistance+Radios< > * distance Etc. Now I'm lost

i've been chuckling at this the whole time!  i have to agree, you guys do have too much time on your hands!   

Et tu Brute .

But seriously,   This stuff should be of practical use to more than a few of us.  I could crank out a spreadsheet that would take the spool diameter and gear ratio as input and would output a one-way bearing rating,   or input  a bearing rating and the reel dimensions, output the max drag before the bearing exceeded the specs.  But not sure how I could post it.   I don't want to go through the work to code up some php and host a web page.  That would definitely support the "too much time on your hands" argument.

Ok,  off to make some reel parts now.   Will try to use as little science as possible 

-J

[mhc]

I tried the crescent wrench with a pull scale on two 349 bridges I have modified with two extra dog posts.



My target was 30 lb drag with a 349H gear ratio of 3.25 to one & full spool. Worked out to be 146 lb/in.
The crescent wrench is 5.25 inch from the centre of the gear sleeve to the hole at the end of the handle where the scale attaches.
146/5.25 = 28lb
I screwed the bridge to a block of wood tried loading the dogs one at a time to 30 lb.


The first two posts and dogs on bridge 1 were OK to 35 lb. The third post was too close to the edge of the bridge and tilted outwards, this raised the dog and the tip causing the dog and gear sleeve ratchet to fail;







I then tried bridge 2 with stainless dogs and gear sleeve. The three posts stood up to around 35 lb but one of my modified dogs started to bend at around 20 lb and failed at 25 lb.
The bent dog is on top in the photo, The back edge started out the same shape as the bottom dog & I had ground out the other side trying to make more room for a spring on a third dog.



I'm glad I tried this, thanks for the idea jurelometer.

[Tightlines667]

Interesting test and results.  Seems like the dog pins that are supported on both ends (sideplate and bridge), as well as those that are mounted further inboard on the bridge should be able to stand up to greater forces.  Looks like it is important for the entire edge, and as much surface as possible, to squarely and cleanly align with the ratchet teeth in order to maintain maximum strength.  I think I may start being a bit more fastidious with regards to replacing dogs showing any noticable signs of uneven wear or marring.

[Alto Mare]

Nice test!  I'm not taking anything way, I thank you for doing this.
I believe you would have had different results if the main gear was in place and the star cranked down. I understand this isn't a drag test, but the gear would have helped keeping the dogs in place.
It appears that the dogs lifted and slipped from the top of the ratchet, something that wouldn't happen in the real world.

Sal

[mhc]

Thanks Sal,
I agree - a gear held in place, with the pressure needed to give the 30 lb drag the test was based on, would probably have stopped the dog from lifting to the point where it slipped. That would have saved the sleeve and dog from the damage they experienced in this test. I was thinking how to do this and still be able to put a wrench on the sleeve and now, after the test, think a metal sleeve with cut out sections on each side to fit the wrench in would work - next time.
The main reason I did this was to test the dog posts (and dogs) I had installed, I was concerned the 3rd posts were too close to the edge of the bridge. The test showed me the post on bridge 1 was too close, if you look at the 3rd photo above you can see the edge of the bridge is deformed - it wasn't before the test. The 3rd post on the 2nd bridge was only a 1/16th or so further in from the edge but held up fine. It also showed me long curved skinny dogs aren't strong - even with stainless. The Penn brass and Lee's dogs were both fine.

Tightlines666 makes a good point - the contact between the dog and ratchet teeth should be as complete as possible to evenly spread the load, particularly with higher drag settings.

Michael

[jurelometer]

Thanks Sal,
I agree - a gear held in place, with the pressure needed to give the 30 lb drag the test was based on, would probably have stopped the dog from lifting to the point where it slipped. That would have saved the sleeve and dog from the damage they experienced in this test. I was thinking how to do this and still be able to put a wrench on the sleeve and now, after the test, think a metal sleeve with cut out sections on each side to fit the wrench in would work - next time.
The main reason I did this was to test the dog posts (and dogs) I had installed, I was concerned the 3rd posts were too close to the edge of the bridge. The test showed me the post on bridge 1 was too close, if you look at the 3rd photo above you can see the edge of the bridge is deformed - it wasn't before the test. The 3rd post on the 2nd bridge was only a 1/16th or so further in from the edge but held up fine. It also showed me long curved skinny dogs aren't strong - even with stainless. The Penn brass and Lee's dogs were both fine.

Tightlines666 makes a good point - the contact between the dog and ratchet teeth should be as complete as possible to evenly spread the load, particularly with higher drag settings.

Michael

Good job! And thanks for sacrificing some parts to educate the rest of us.    A little mechanical  engineering, a little bench testing, a little real world experience-  all from different viewpoints.  this is what I like!



I would think that you could add on the whole gear/drag assembly with the exception of the spacer sleeve. Tighten the drag down to the same level as when the reel is set to the target drag.  There should be room to slip a small wrench onto the shaft.  This is closer to real life, and a more useful the simulation as others have pointed out.   Having the plate on the bench allows you to see what is probably happening inside the reel.  It is probably worthwhile to know if the failure will be due to dog mis-alignment or pin bending.

If you want to estimate the force on the pin and or dog, multiply the torque on the the main shaft in lb-in by the distance (radius) from the center of the ratchet to the center of the ratchet tooth engagement with the dog.


Regarding the sync vs async multi-dog question- I have been hesitating to dive into religion, but here goes the mechanical aspects:  

1.  Synchronized dogs do not generally share load until something bad starts to happen.  The pin/dog/ratchet system is not very elastic- so the first dog takes all the force until it starts to fail.   Once it starts to fail the second dog will take a over the load- with potentially some sharing, depending on the damage  

You don't get the benefit of the second dog until the first dog is overloaded.  But at that point you have a better chance of all of the parts still being in place, so the reel can still function.

2.  Asynchronous dogs will give you less handle backplay, but when  a dog fails- it is much worse.  It will fail more completely, and there  will be greater impact force on the second dog as the ratchet goes flying backward.  More chances of the second dog blowing out or having the first dog remnants jamming the reel.

If I was designing a reel from scratch, I would design the dogs to handle the max load, and make them asynchronous.   If I was customizing a reel it is a bit trickier, and to some extent, depends on my goal.

I'm going to try to attach a calculator.  It is a Word document with embedded worksheets.  click on the worksheet and modify the cells in yellow to match your reel specs.   Let me know if this works.


-J.

[Alto Mare]

Regarding the sync vs async multi-dog question- I have been hesitating to dive into religion, but here goes the mechanical aspects:  

1.  Synchronized dogs do not generally share load until something bad starts to happen.  The pin/dog/ratchet system is not very elastic- so the first dog takes all the force until it starts to fail.   Once it starts to fail the second dog will take a over the load- with potentially some sharing, depending on the damage  

You don't get the benefit of the second dog until the first dog is overloaded.  But at that point you have a better chance of all of the parts still being in place, so the reel can still function.

2.  Asynchronous dogs will give you less handle backplay, but when  a dog fails- it is much worse.  It will fail more completely, and there  will be greater impact force on the second dog as the ratchet goes flying backward.  More chances of the second dog blowing out or having the first dog remnants jamming the reel.

If I was designing a reel from scratch, I would design the dogs to handle the max load, and make them asynchronous.   If I was customizing a reel it is a bit trickier, and to some extent, depends on my goal.

I'm going to try to attach a calculator.  It is a Word document with embedded worksheets.  click on the worksheet and modify the cells in yellow to match your reel specs.   Let me know if this works.


-J.

Dave, I disagreed with you about this earlier and I'm going to disagree with you again . The way a fishing reel is designed, with dogs and ratchet, having  the dogs engage at the same time, the force will be shared by both.
I do not believe that one of the dog gets most of the load, unless that dog engages a little earlier than the other.
This would definitely be a good test to see if I'm right or the formula is, but I  already have a bucket full of damaged parts, so I let someone else prove me wrong.
Sal

[mhc]

Interesting comments on the sync V async dogs issue. With the long curved skinny dog that bent during the test, a second dog close to being in sync might have saved it - which is what you said. The first to take the load needs to flex or deform before the second takes some of the load. The amount of flex or deformation needed would depend on how close the dogs are to being perfectly synchronized.  

The link & spreadsheets work fine - thanks. Should the force on the dogs calculated in the third sheet be the torque divided by the radius ie; decreasing as the radius increases for a given torque?

[jurelometer]

Regarding the sync vs async multi-dog question- I have been hesitating to dive into religion, but here goes the mechanical aspects:  

1.  Synchronized dogs do not generally share load until something bad starts to happen.  The pin/dog/ratchet system is not very elastic- so the first dog takes all the force until it starts to fail.   Once it starts to fail the second dog will take a over the load- with potentially some sharing, depending on the damage  

You don't get the benefit of the second dog until the first dog is overloaded.  But at that point you have a better chance of all of the parts still being in place, so the reel can still function.

2.  Asynchronous dogs will give you less handle backplay, but when  a dog fails- it is much worse.  It will fail more completely, and there  will be greater impact force on the second dog as the ratchet goes flying backward.  More chances of the second dog blowing out or having the first dog remnants jamming the reel.

If I was designing a reel from scratch, I would design the dogs to handle the max load, and make them asynchronous.   If I was customizing a reel it is a bit trickier, and to some extent, depends on my goal.

I'm going to try to attach a calculator.  It is a Word document with embedded worksheets.  click on the worksheet and modify the cells in yellow to match your reel specs.   Let me know if this works.


-J.

Dave, I disagreed with you about this earlier and I'm going to disagree with you again . The way a fishing reel is designed, with dogs and ratchet, having  the dogs engage at the same time, the force will be shared by both.
I do not believe that one of the dog gets most of the load, unless that dog engages a little earlier than the other.
This would definitely be a good test to see if I'm right or the formula is, but I  already have a bucket full of damaged parts, so I let someone else prove me wrong.
Sal

We are in agreement that the second dog cou;d kick in at some point well  before catastrophic failure.  The damage may be so insignificant that we could categorize is it as "settling in".

It is virtually impossible to machine ( not to mention die, laser, or water jet cut) a synchronous multi-dog/ratchet system that is so accurate that both dogs will contact the ratchet at exactly the same moment.  So now we are relying on something to give way for the load to be shared.  The dogs are not going to compress and expand.  If a particular reel is elastic at this location (e.g. a  bridge plate or dog pin that flexes a bit under load)- then you may begin to get some load sharing before any damage or wear of significance occurs -Notice that I  am  I am  cleverly backtracking a tiny bit here .   

How much flex there is in the system depends on the reel design.    I would also go with the bucket of bricks test approach on this and not material deformation calculations   
     
-J

[jurelometer]

Interesting comments on the sync V async dogs issue. With the long curved skinny dog that bent during the test, a second dog close to being in sync might have saved it - which is what you said. The first to take the load needs to flex or deform before the second takes some of the load. The amount of flex or deformation needed would depend on how close the dogs are to being perfectly synchronized.  

The link & spreadsheets work fine - thanks. Should the force on the dogs calculated in the third sheet be the torque divided by the radius ie; decreasing as the radius increases for a given torque?

Oops!      Thanks!!! -  more proof that my my math is not to  be trusted.  Updated the post with the corrected spreadsheet (version 2 in title).

You are correct.  That is why a bigger ratchet is better (and more common on newer reels)-  you can fit more smaller teeth on it (less backplay)  and still have a stronger anti-reverse.

[Alto Mare]

Dave, being in construction for over 40 years and building things by hand, I tend to lean towards actual tests instead of formulas, sorry, its just the way I am, so be patient with me , I do enjoy all that you've been showing us.

On the dogs, giving  the right amount of force and causing some flex with the dogs or ratchet, do you believe the two dogs would share the load? I believe there would definitely be some flexing and I also believe at some point the load would be shared.
When that does happen, I couldn't tell you, I'm not that smart, but I do believe it would also be related to the material used and not just the amount of force applied.

Your statement makes sense to me, about never being able to having true synchronized dogs, but under the right conditions while using the tool, it could be.

Not related and pulling away from this, do you believe double dogs is a better choice than just one dog in fishing reels? and the you also agree that trying to get them synchronized is a better choice than alternating?

Sal