Straightening a 6” diameter Rudder Stock.

[jackieschmidt]

I mention on occasion that we do precision straightening of large Prop Shafts and Rudder Stocks rhat come out of Push Boats.

I had to do this yesterday, one of our customers dropped it off.

For those that do not know, a Rudder Stock is a vertical shaft in a boat that the rudder blade is welded on to. The upper portion fits in a tube with a bearing at the bottom and one at the top of the rudder tube. There is a tiller arm installed on a keyed taper at the very top all held together by a large not.

this is our smallest “straightening rig”. It has. 175 ton Jack. We have three more, a 300 ton, a 500 ton, and a 750 ton.

Straightening things like this with massive tonnage is as much of an art as it is a skill. You have to analyze exactly where the bend begins, and work it out. The arms are adjustable, so you can place tonnage at any specific point and make the piece straighten exactly where you want it too. We have a graduated 10,000 PSI gage on out pumps so I know exactly how much tonnage I am applying.

I call this “applying precision tonnage”.

We do quite a bit of this. Some as large in diameter as 12 inches.

here is a couple of pictures of before, with the rig in place, and after straightening.
one thing to note, this puts no strain on the lathe. All of the pressure is contained in the straightening rig.

 

[jackieschmidt]

Here is a 8 inch rudder stock I was getting set up to straighten a week ago using our 500 ton straightening rig.

Also, here is our 300 ton rig straightening the coupling end of a 8 inch shaft during a rebuild, ( top picture).

 

[TaperPin]

Wow - I’ve only done that with a little tiny 1” leadscrew and can appreciate how difficult something like that must be. The huge tonage of your jacks must produce some dangers that normal shops don’t see?

 

[BoydAllen]

Wow! Really impressive. Thanks for sharing and all the pictures. I always enjoy your posts.

 

[LVLAaron]

This is not the rudder stock I expected.

 

[durand mortenson]

Jackie
Good to see your shop again Don't recall ever seeing this operation
As usual great photos.
Once you bend it how do you measure it for straightness?
Mort

 

[jackieschmidt]

Jackie
Good to see your shop again Don't recall ever seeing this operation
As usual great photos.
Once you bend it how do you measure it for straightness?
Mort

The part that hangs off the bottom that the blade welds to is kind of a “visual”. If it is within 1/8 inch, that’s fine.
However, where the bearing journals are have to be dead straight, as they fit in the bearings of the rudder tube.

We generally re clad the journals with SS and remachine them dead true anyway.

Here is what the rudders looks like in typical 2000 HP push boat. And the tiller arm atop the rudder tube.

 

[jackieschmidt]

Here are the Journals being re machined. Notice the Submerged Arc weld beads.

 

[durand mortenson]

The part that hangs off the bottom that the blade welds to is kind of a “visual”. If it is within 1/8 inch, that’s fine.
However, where the bearing journals are have to be dead straight, as they fit in the bearings of the rudder tube.

We generally re clad the journals with SS and remachine them dead true anyway.

Here is what the rudders looks like in typical 2000 HP push boat. And the tiller arm atop the rudder tube.View attachment 1483665View attachment 1483658

Like the shot right behind the steady rest. Shows it all.
What kind of camera do you use?
Have you tried a level placed some where in the shop with a precision laser for measuring horizontal dis placement? I'm Just winging it here.
Your shop photos remind of back when...I can almost smell the place. It became a hazardous work site and was torn down.
Mort

 

[jackieschmidt]

Like the shot right behind the steady rest. Shows it all.
What kind of camera do you use?
Have you tried a level placed some where in the shop with a precision laser for measuring horizontal dis placement? I'm Just winging it here.
Your shop photos remind of back when...I can almost smell the place. It became a hazardous work site and was torn down.
Mort

Admittedly, in todays world of machine shops, we are a “niche” industry.

We have no CNC equipment.The bulk of our work simply does not lend its self to it. We do not have operators monitoring machines, we have Machinist running machines.

The main reason we are successful is very few people are willing to do this type of work. But it has to be done.

 

[durand mortenson]

Admittedly, in todays world of machine shops, we are a “niche” industry.

We have no CNC equipment.The bulk of our work simply does not lend its self to it. We do not have operators monitoring machines, we have Machinist running machines.

The main reason we are successful is very few people are willing to do this type of work. But it has to be done.

Thanks Jackie
Appreciate your response

Mort

 

[LVLAaron]

I look forward to having a little job shop when I retire from my day job in 10 years. It's amazing how many people have reached out (Here, and in real life) to have something fixed/repaired/altered just because I can run a lathe and a mill, and weld a little bit.

 

[ShtrRdy]

This sort of thing boggles mind. Since I've lived in the middle of the US all of my life I had no idea this sort of thing was done and to what scale. Thank you of showing and describing this sort of work.

 

[topclass2017]

thank you, Jackie, for your post. I always enjoy seeing and reading about the work you do. The scale is what I find so impressive. Like so many things these days, it is becoming a lost art (as you say) that few and fewer practice.

 

[Rat Rifle]

Here are the Journals being re machined. Notice the Submerged Arc weld beads.View attachment 1483668

Only the “TRULY BLESSED” are allowed to have “THIS MUCH FUN” !!

 

[Uncle Bruce]

I mention on occasion that we do precision straightening of large Prop Shafts and Rudder Stocks rhat come out of Push Boats.

I had to do this yesterday, one of our customers dropped it off.

For those that do not know, a Rudder Stock is a vertical shaft in a boat that the rudder blade is welded on to. The upper portion fits in a tube with a bearing at the bottom and one at the top of the rudder tube. There is a tiller arm installed on a keyed taper at the very top all held together by a large not.

this is our smallest “straightening rig”. It has. 175 ton Jack. We have three more, a 300 ton, a 500 ton, and a 750 ton.

Straightening things like this with massive tonnage is as much of an art as it is a skill. You have to analyze exactly where the bend begins, and work it out. The arms are adjustable, so you can place tonnage at any specific point and make the piece straighten exactly where you want it too. We have a graduated 10,000 PSI gage on out pumps so I know exactly how much tonnage I am applying.

I call this “applying precision tonnage”.

We do quite a bit of this. Some as large in diameter as 12 inches.

here is a couple of pictures of before, with the rig in place, and after straightening.View attachment 1483611View attachment 1483612
one thing to note, this puts no strain on the lathe. All of the pressure is contained in the straightening rig.

Do you have to go past straight to allow for a little spring back on something that heavy. Like straighing an aluminum arrow?

 

[jackieschmidt]

Do you have to go past straight to allow for a little spring back on something that heavy. Like straighing an aluminum arrow?

Yes, that is all part of it. After you get it close, you watch your pressure gage on the pump to see exactly how much pressure moves it a certain amount. If you go past, you can just go the other way.

These Shafts and Rudder Stocks are all made from 1022 hot rolled mild steel. The spring back is minuscule compared to what an alloy steel such as 4140 has.

We have straightened as big as 8 inch 17 AQUAMET Stainless, which is 17-4 at H1150. Its spring back can be as much as 10% past Straight. Luckily, not too many companies use it in anything past 6 inches.

 

[durand mortenson]

I look forward to having a little job shop when I retire from my day job in 10 years. It's amazing how many people have reached out (Here, and in real life) to have something fixed/repaired/altered just because I can run a lathe and a mill, and weld a little bit.

Sounds like a good plan. Hope it works out for you.

Mort

 

[durand mortenson]

Only the “TRULY BLESSED” are allowed to have “THIS MUCH FUN” !!

I think Jackie might have a video on that process if you are interested.

Mort

 

[tikkaman308]

Pretty impressive set up,I do quite a bit of shaft straightening in my line of work. We rebuild big industrial pumps for ,wastewater,power generation and drinking water plants. Most of the time the shafts on a vertical turbine pump will have to be straightened, whether they are being used or brand new.Most of our shafts are 300/400 series stainless steels or 4140,with the stainless shafts we use heat to straighten them to under .002 if they are 4140 we have to mechanically bend/straighten them. People doing the work that you and myself do are a dying breed,it's dang near impossible to find a machinist that can run a manual lathe these days.