Yuloh What I'm Talking About

[fred1diver]

I am trying to really understand what you are trying to do with the ferrules, 1/16” is not that much, could you shave it on the wood?
how long do you need the end result to be? You mention you have 13”
Do you have a diagram of what you want to end up with?
I am not sure I understand the bend you need to accomplish, I have a machinist friend, I might be able to ask for work arounds for you to save money and time

 

[Will Gilmore]

I'm working with the idea that I'll have at least a 6" overlap of the wood into the ferrules. I'll attach one side permanently (screws, and/or epoxy), the other side will slide in, a small pin keyway to prevent twisting, and 5/8" bungee to hold them together. I'd like to keep the wood shaft (loom) at the full 2" OD for strength, so the ferrules need a full 2" ID.

I also need to bend the loom at the top quarter by about 10 degrees. I thought introducing the bend into the ferrule would be the best way to do that. I could do it with the wood, if I have to, but that seems like a weaker option. The only real problems I have with the 3/16+ wall thickness are the ID is too small, and the bronze is very heavy. Much heavier than the rest of the yuloh.

-Will

 

[dLj]

I'm working with the idea that I'll have at least a 6" overlap of the wood into the ferrules. I'll attach one side permanently (screws, and/or epoxy), the other side will slide in, a small pin keyway to prevent twisting, and 5/8" bungee to hold them together. I'd like to keep the wood shaft (loom) at the full 2" OD for strength, so the ferrules need a full 2" ID.

I also need to bend the loom at the top quarter by about 10 degrees. I thought introducing the bend into the ferrule would be the best way to do that. I could do it with the wood, if I have to, but that seems like a weaker option. The only real problems I have with the 3/16+ wall thickness are the ID is too small, and the bronze is very heavy. Much heavier than the rest of the yuloh.

-Will

I'm not understanding the bend? Here's the image you posted before showing the ferrules - can you explain a bit better, maybe a sketch showing where you are thinking to put the bend? In this image ferrules are all straight...

dj

p.s. you said above you'd screw or epoxy the ferrules on - if you could heat shrink them on that would be a very good way to do it. That's how we did the mast bands on the Morgan.

 

[Will Gilmore]

That image is a Nano Banana interpretation of a Gemini interpretation. The typical Asian yuloh has a bend in the loom just above the pivot on the transom. It helps with the feathering angle of the sweep.

Here's Gemini's interpretation.

I am not at home, so I don't have a way to draw it myself. There are a few details that are not accurate to what I am making, but this is the idea. The blade won't be wide or asymmetrical like the one shown here. There also won't be a long curve in the top of the loom. It will be confined to the top ferrule.

Don't go by those measurements. They are whacky.

-Will

 

[Will Gilmore]

if you could heat shrink them on that would be a very good way to do it.

What kind of tolerance do I need for heating? Do I make the ID 1-15/16", 1-31/32"? What temperatures am I looking at for this technique? I like the idea of it.

-Will

 

[dLj]

What kind of tolerance do I need for heating? Do I make the ID 1-15/16", 1-31/32"? What temperatures am I looking at for this technique? I like the idea of it.

-Will

If you run your ferrule up to about 1200 F you can use the 1/16" number. I'd probably run a light 1/16" meaning it would actually be a 1-61/64" tolerance. But the hot ferrule will help on that.

You need to work fast, you will find the wood smokes and you have to then quench in water quickly. You can soak the wood in water before doing this to minimize the wood burning (bronze has a high heat capacity), but a small amount of charred wood surface under the ferrule is actually beneficial to keep the wood in that area from decaying over time. Charred wood surfaces resist rot over time.

Of course this is all dependent upon if you have exactly a 2" diameter piece you're putting this on. Have you measured it?

dj

 

[Will Gilmore]

Thanks dj.

Have you measured it?

I'm making it. It will be whatever I decide, with at most 2". I can turn it down, if I need to, but 2" is the plan.

-Will

 

[dLj]

Thanks dj.

I'm making it. It will be whatever I decide, with at most 2". I can turn it down, if I need to, but 2" is the plan.

-Will

Then I'd suggest you first make your ferrules then turn your wood to the size needed. Seems to me to be a whole lot easier than matching the ferrule to the wood in this case....

dj

 

[Will Gilmore]

An update about the ferrule pieces. I was mistaken about the type of bronze. I thought I was ordering 954 bronze, an aluminum marine bronze, but what I got is apparently 932 (SAE 660) bearing bronze. The alloy includes lead, not aluminum. I don't know what difference that will make to the finished project, but the online information says I can't weld SAE 660, and the fumes can be very bad for me. I've got one bored out simply by sanding it with 60 grit on a dowel with progressively larger diameters. It wasn't too bad, and the wall thickness is definitely better. I'm thinking I need to join the two sides by bolting a brass plate to the sides and along the inside and outside of the elbow. More work and time looking for materials.

Maybe I need to scrap the 932 and try to get the 954. I'm guessing the aluminum bronze will be lighter.

-Will

 

[dLj]

You can braze the 932. You won't notice a difference in weight between it and aluminum bronze.

dj

 

[Will Gilmore]

I was given the impression brazing would be strong enough for the back and forth of the rowing. Is that not the case?

-Will

 

[dLj]

I was given the impression brazing would be strong enough for the back and forth of the rowing. Is that not the case?

-Will

Yes, it would be strong enough. That's why I suggested it.

dj