Align Boring The Struts And Stern Tube In A New Corps Of Engineers Push Boat

[jackieschmidt]

We are in Port Arthur Tx this week align boring the shaft lines in a new Corps of Engineers Tug that Vessel Repair is building. The holes are 11 inches ID. This will be a 2600 HP vessel. It will have 8 3/4 prop shafts.
the bearings will be Thordon Rivertough that we will freeze in with liquid nitrogen.

RiverTough Tailshaft Bearings

thordonbearings.com

Here are a few pictures.

 

[jackieschmidt]

Finished bores on the Starboard side.

 

[Ggmac]

All I can say is AMAZING WORK !

 

[Mdhmsmith]

What king of tolerances are you shooting for on big stuff like that?

 

[jackieschmidt]

The bars cut amazingly round and straight considering the environment we work in.

I can count on around .002 out of round on a hole this big, straightness being about the same. A little tool wear accounts for it not being dead straight. As far as finish, a 125 is ok, View attachment 1426712

The main object in work like this is to get the bearing fits dead in line With each other so the shaft does not run in any deflection. The shipyards can usually fabricate them in to within about 1/4 inch. Keep in mind, there is a lot of weld to pull things askew.

But then, that is why we come in and align bore everything.

 

[Judd]

Always fascinated by your posts…very cool!

 

[Dusty Stevens]

Your men do good work even with a broken welder

 

[Walt Schmidlin]

Always impressed with your work and postings. Do you notice any difference in alignments/deflections performed under cloudy conditions versus bright sunny days even though you appear to be working in a partially covered area?

 

[jackieschmidt]

Always impressed with your work and postings. Do you notice any difference in alignments/deflections performed under cloudy conditions versus bright sunny days even though you appear to be working in a partially covered area?

I am actually not in a covered area, the boat is sitting on a Drydock.

as to your question, yes.

We can set up a music wire or shoot in a laser in the cool of the morning, and in the heat of the afternoon Sun you can pick up a difference. Not much, but you can see it.

Push Boats tend to be short and stiff in construction, so we consider this a non issue.

 

[AlNyhus]

Amazing work, Jackie. On a side note, lots of great music came out of Muscle Shoals. -Al

 

[jackieschmidt]

Amazing work, Jackie. On a side note, lots of great music came out of Muscle Shoals. -Al

Indeed it did, Al. Amazing some of the world famous artist that held sessions there.

This boat is well named as it will be working the Tombigbee Waterway and Tennessee River.

 

[hpshooter]

Thanks for sharing, always interesting.

 

[BoydAllen]

Always interesting...thanks again.

 

[ronsatspokane]

I'm always fascinated by the work you do. There can never be too many pictures. Love looking at them.

 

[jackieschmidt]

I'm always fascinated by the work you do. There can never be too many pictures. Love looking at them.

Here is what the inboard bearing mount looks like for the 4” diameter boring bar. As you can see, the bearing in the seal mounting plate has external bolts that allow me to place it in the center of the seal mount.

The seal assembly, which bolts to the mount, is also made by Thordon. These are considered “zero leakage” units.

Shaft Seals

thordonbearings.com

The Stern Tube, which will contain the hull River Tough Bearing on the outboard end, is 7 foot long.

 

[55fairlane]

As always way kewl!

What kinda material are the bearing houses made out of?

What kinda speeds & feeds are you using?

.002 taper & out of round on that large of bore is really awesome.

Your work , sir, is like magic!

 

[jackieschmidt]

As always way kewl!

What kinda material are the bearing houses made out of?

What kinda speeds & feeds are you using?

.002 taper & out of round on that large of bore is really awesome.

Your work , sir, is like magic!

1026 tubing.

ASTM A519 Grade 1026 Carbon Steel Seamless Tubings – Ferropipe

ASTM A519 Grade 1026 Carbon Steel Seamless Tubings are Medium Carbon Steel Tubings with 0.22-0.28 % carbon content with combination of 0.60-0.90 % manganese. These Tubings are most commonly used for general purpose applications worldwide.

ferropipe.com

the bars turn around 30 rpm on a hole this size. It takes around 2 hours to take A cut through the 32” long strut tube. It seems slow, but we can take fairly large cuts rough it out. As you can see in this picture, that is about a 5/16 wide cut.

 

[Walt Krafft]

And your bore has to line up with the reduction unit, which has to line up with the engine. Where do you start from?

 

[jackieschmidt]

And your bore has to line up with the reduction unit, which has to line up with the engine. Where do you start from?

You start with the shaft line and work forward.

The shaft line is align bored in its proper position in the hull. Then with the bearings in place and the prop shaft installed, you align the reduction gear output Coupling to the prop shaft coupling. After the reduction gear is chocked in, you align the engine to the reduction gear input.

The gear and engine alignments are performed after the vessel is in the water and ballasted to an average running condition.

here is a picture of the reduction output mated to the shaft coupling in a similar installation.

 

[Uncle Bruce]

You start with the shaft line and work forward.

The shaft line is align bored in its proper position in the hull. Then with the bearings in place and the prop shaft installed, you align the reduction gear output Coupling to the prop shaft coupling. After the reduction gear is chocked in, you align the engine to the reduction gear input.

The gear and engine alignments are performed after the vessel is in the water and ballasted to an average running condition.

here is a picture of the reduction output mated to the shaft coupling in a similar installation.
View attachment 1426981

Do you need to use a cooling liquid on the tools, or do you have to change them out after a cut or two?