10" diameter rudder straightening

Butch Lambert · Apr 30, 2020

I've posted photos of my bud's shop in Houston. They manufacture, repair, and other shaft work Pictures show a shaft that is a little bit bent and after.
YouTube
YouTube
From Jackie: This came in yesterday on a emergency dry docking. I set it up and straightened it.

This is one our more lucrative services, since few shops have the equipment to precision straighten this large of a piece. The rig you see hanging is our 700 unit.

It took me and one of my men about Three hours to set It it up and straighten it.

Well, it’s kinda proprietary. We will not even let customers watch us do this.

But if you take a look at that straightening rig, you can get an idea how we do it. The arms are adjustable, allowing us to put tonnage exactly where we want to apply it, making the piece bend in the correct spot. Using one of these is as much of an art as anything.

We have 4 of these rigs in different sizes. A 150 ton, a 350 ton, a 500 ton and this one. They operate on 10,000 psi maximum. The arms and strong backs are made from T-1 plate.

We designed and built these ourselves. I refer to the process of straightening as applying Precision Tonnage

TGTool · Apr 30, 2020

Thanks. An interesting rig and its always interesting hearing about proprietary solutions and expertise. Elegant solutions might be poetry in metal in our business.

DDoug · Apr 30, 2020

Butch Lambert said:
Well, it’s kinda proprietary. We will not even let customers watch us do this.

And yet you posted it on the World Wide Web ????

Butch Lambert · Apr 30, 2020

digger doug said:
And yet you posted it on the World Wide Web ????

Yes sir young feller. I guess ain't nuttin secret anymore. Bet you will start taking his bidness tomorrow.

TGTool · Apr 30, 2020

digger doug said:
And yet you posted it on the World Wide Web ????

Well, it might be like Rich King says about scraping. Just knowing how to shave off a scraping is easy. Knowing exactly where and how much is what earns the big buck. Anybody with even a little machine sense can figure out a frame and cylinder. Knowing how and where and how much is what separates their business from the three day's I would take and still not have it satisfactorily straight.

But of course your point that nothing on the web is private anymore is well taken. I'm sure the FBI and homeland security know what I like for breakfast and whether I cheat on my girlfriend.

DDoug · Apr 30, 2020

TGTool said:
Well, it might be like Rich King says about scraping. Just knowing how to shave off a scraping is easy. Knowing exactly where and how much is what earns the big buck. Anybody with even a little machine sense can figure out a frame and cylinder. Knowing how and where and how much is what separates their business from the three day's I would take and still not have it satisfactorily straight.

But of course your point that nothing on the web is private anymore is well taken. I'm sure the FBI and homeland security know what I like for breakfast and whether I cheat on my girlfriend.

Butch Lambert said:
Yes sir young feller. I guess ain't nuttin secret anymore. Bet you will start taking his bidness tomorrow.

Look. I think it's great you posted it.

But that comment about not letting anyone see it, has me wondering if your friend doesn't know you posted it eh ?

atomarc · Apr 30, 2020

In all fairness to the OP, he showed a very short clip of the bent shaft (before) and a very short clip of the straightened shaft (after) but he did not show how it was done..so WWW aside, it's still a secret, right.

Stuart

thomj · Apr 30, 2020

It is my experience that something like that, has been deformed and yielded, is very likely to returned to its yielded state. Meaning its going to bent back in short order. Is there some way of avoiding this? Maybe you know something I don't. If that is the case, I would love to hear about it.

Thank You,
Thom J

Garwood · Apr 30, 2020

thomj said:
It is my experience that something like that, has been deformed and yielded, is very likely to returned to its yielded state. Meaning its going to bent back in short order. Is there some way of avoiding this? Maybe you know something I don't. If that is the case, I would love to hear about it.

Thank You,
Thom J

I've formed a lot of parts in presses and have never once had one jump back into the shape it was before.

When I was about 19 I straightened out the NP435 shifter in my 1970 F-250. You wouldn't know it was ever bent. It hasn't returned to it's prior state yet. That was 20 years ago. Guess it could still happen.

Tony Quiring · Apr 30, 2020

It was likely bent by some unwanted force like a lack of water.

This process "allowed" it to return to natural state...

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thomj · Apr 30, 2020

Garwood said:
I've formed a lot of parts in presses and have never once had one jump back into the shape it was before.

When I was about 19 I straightened out the NP435 shifter in my 1970 F-250. You wouldn't know it was ever bent. It hasn't returned to it's prior state yet. That was 20 years ago. Guess it could still happen.

Yes, I have had the same experience. But what about when the rudder shaft encounters an extreme load? Like the one that bent it in the first place? For example, I bent a truck frame when I was young. Had it straightened. Drove nice... For awhile. Then it went back. I have straightened 2" dia. line shafts in printing presses for quicker repair. But they eventually go back. Destroying all of the carriers and gears along the way. I have seen that. I might straighten a shaft on a weekend break down so I can get home and go back to bed, but monday morning I would be planning a replacement and schedule a down time. I suspect that shaft will be bent again.

Thom J

guest · Apr 30, 2020

If I had to guess, I'd say the bend was caused by a grounding.

I straightened a rudder post once (much smaller), it's one of those things you get one try. They have a memory, and if you get it right, they will go right back to dead straight.

Get it wrong, you end up with a corkscrew, you will chase it around all day long and never get it back.

It's definitely an art.

ratbldr427 · May 1, 2020

I have used a much cruder same principal device over the years to straighten shafts ,poles ect in place.
When I started at our old plant one of our sheeters got hit(forklift) and bent two uprights that held the overhead delivery.While two other guys were planning to jack up and remove them and bring them into the shop I grabbed some chain and heavy wall square tube and a portapower and straightened them better than they were before they got hit.

Thread the chain through the tube and loop the ends around the pole equidistance from the high spot,position the portapower on the high spot and straighten.Rinse and repeat on all the other bends.

I had thought about making some quick connect hooks to get away from the chain but every job like that is different.Turned an all day job into an hour job.

eKretz · May 1, 2020

Oh brother. There's nothing proprietary about this. If you have worries about memory effect bend part back straight then about 50% in opposite direction to original bend then come back to straight again. It ain't likely on a shaft that big.

Cole2534 · May 2, 2020

TGTool said:
and whether I cheat on my girlfriend.

...well, long as your wife doesn't....

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steve-l · May 2, 2020

Garwood said:
I've formed a lot of parts in presses and have never once had one jump back into the shape it was before.

When I was about 19 I straightened out the NP435 shifter in my 1970 F-250. You wouldn't know it was ever bent. It hasn't returned to it's prior state yet. That was 20 years ago. Guess it could still happen.

Have you ever straightened a prop shaft made of Accumet? If you have, you would understand the comment better. In that material it is usual to use the spot heat shrink process, because it usually then stays straight.

TGTool · May 2, 2020

TGTool said:
... and whether I cheat on my girlfriend.

Cole2534 said:
...well, long as your wife doesn't....

Sent from my SM-G930R4 using Tapatalk

You don't think I'd post anything personal here that had any relevance to the truth, do you? "And having muddied the well of inquiry with the stick of imagination ..."

jmead · May 2, 2020

thomj said:
It is my experience that something like that, has been deformed and yielded, is very likely to returned to its yielded state. Meaning its going to bent back in short order. Is there some way of avoiding this? Maybe you know something I don't. If that is the case, I would love to hear about it.

Thank You,
Thom J

Definitely, if they hit that rock again.

johansen · May 2, 2020

If you use a flame straightening process but dont heat deep enough, or dont anneal the material, you have a shaft that is not in a relaxed state at the end of the process.

So say you have an i beam at 40kpsi yeild.

It got bent so you flame straighten it, leaving 25ksi stored in the flange (and you may not know where or in what direction), but it is straight.. Now it only takes a 15ksi load to bend it again.

tobnpr · May 2, 2020

Off an aircraft carrier :eek:

?
Jeez...I can't imagine a rudder post that size. IIRC those on the 40'er I owned were all of 1-1/2".
Yard that I used, used flame treatment for straightening. Wouldn't seem feasible on shafting that size.

10" diameter rudder straightening

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