Fitting a large propeller to shaft

[AWS]

My father was a machinist in a rock crusher building plant and ran a boring mill with a 12' table, he would cut the inside threads on large gyrosphere rock crushers. One day he took my little 25hp outboard block in and set it up on that boring mill and took a few thousandths off to raise the compression for me. It was fun watching him use this huge machine that could turn 6 ton crusher frames taking just a little bit off of a 10 lb engine block. He'd turn fancy mushroom anchors for the guys fishing boats on it also.

I spent a couple summers there assembling portable rock crushing equipment and crushers themselves. Great job, I learned alot.

 

[rwj]

I guess everybody in the boat business has been doing it wrong.

Not at all, just pointing out that retaining devices are a safety/redundant feature when a tapered joint is properly done. I’ve used bolted end plates on the tapered joints that I’ve assembled and have found them loose/missing on the joint years later with the taper still locked.

 

[jackieschmidt]

This is how the coupling is held on on the forward end of most shafts.

most shipyards will make the coupling up tight with the bolts, then warm the coupling body to around 250 degrees, then retighten the bolts. After the coupling cools, tighten bolts again to the subscribed torque and secure with wires.

the tapers on these shafts are usually 1 inch per foot. You tighten the nut or bolts to advance the prop or coupling up the taper around 1/16 of an inch after firm seating By warming the hub.This will be the equivalent of a shrink fit of approx .005 to .007 inch.

 

[garandman]

Dang.

 

[M-61]

My father was a machinist in a rock crusher building plant

There are two near Poughkeepsie NY. They were brought here when they finished work on the Panama Canal. Still in use.

 

[AWS]

It was kind of interesting the government spec'd a batch of combination crushing and screening unit that were mechanically driven, belts and chains for shipping to third world countries, it was interesting building them working off of old blueprints(everything modern had electric motors run from a main control panel).

The really strange part as when I was stationed in Chu Lai, Vietnam(Seabees 1968-69) Philco-Ford had one of them at their batch plant so I got to see one of the ones I worked on in operation.

Back to tapered shafts, the heads on cone crusher run on a large eccentric tapered shaft the heads on the largest crusher was 66" across. They would turn it upside down, set it on a stand and place burners around it and heat it to near cherry red. Then someone would have to stand over the head and guide the shaft into the head. the only thing that worked to stand on were large oak timbers, they tried metal beams but before the shaft could be set the workers boot soles would melt. It is very un-nerving standing on that timber with flames bursting up on each end where it was laying on the head. This was in the old days when you finished you didn't have to cross over the flames to get off you just grabbed the crane hook and the operator would fly you off. I got to do both parts of the job , guiding the shaft into the head and after I came back from Vietnam running the 80 ton overhead crane lowering the shafts into place.

Surprisingly rock crushers have very close tolerances, if there is any slop they will tear themselves apart.

It was fun to see all different things that get crushed. We set up a jaw crusher that they would bring various stuff into crush, the two that I still remember were cast iron engine blocks and bowling balls we had to build a cover for the crusher as the bowling balls wanted to bounce out.

 

[jdh47]

Those taper fits are not going to come loose unless made to. They do it that way for a reason.

 

[Brians356]

This is how the coupling is held on on the forward end of most shafts.

most shipyards will make the coupling up tight with the bolts, then warm the coupling body to around 250 degrees, then retighten the bolts. After the coupling cools, tighten bolts again to the subscribed torque and secure with wires.

When you chaps are ready to step up beyond the small stuff, there's always capital ship propulsion shafts sections. This is not even the largest, it's for a new class of guided missile frigate being built in 1957 at Puget Sound Naval Shipyard, the first of the largest shaft forgings ever made on the Pacific Coast. The 2,200-ton hydraulic forging press is hammering a 116,000-lb, 46-in octagon billet into a 24-in diameter shaft with 40-in dia. collars. The shafts were then scaled and moved to the machine shop for turning and "trepanning" (cored, described below.) There's a workman near the center of the bottom photo for scale.





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[Trophied]

Really big equipment is neat to see in action. From watching them work I always thought Drop Hammer Forges were more fun than Hydraulics. Cool to watch the entrained imperfections get blasted out of the material when the hammer hits it.

 

[butchlambert]

I love going to Commerce Grinding in Dallas. Their Blanchard grinder is a huge beast. A list of their blanchard and surface grinders.

Commerce Grinding Company - Chrome Plating Equipment

Commerce Grinding Company. Home of the world's largest rotary surface grinder.

commercegrinding.com

 

[jackieschmidt]

Here are the shafts all rebuilt and ready to be shipped. Also, a picture of the Harbor Tug in dry dock at South West Shipyard.

 

[jackieschmidt]

We are finishing up our last tasks on the boat I pictured in post #26. The boat was launched last month.

After the reduction gears and engines are aligned to the prop shaft, we drill and ream the foundation holes and add a body fit bolt to each gear foot and on each engine rail.

the gear bolts are 1 1/2 and the engine bolts are 1 1/4. To drill holes this large, we use the big Ingersol Rand pneumatic drills. The set up is just a rig I make up to get in tight spots and guide and hold the drill securely.

it all looks kinda crude, but does a great job.

Here are some pictures of the engine room, shafts, and generator room.

This boat will be ready to sail next month.

 

[jackieschmidt]

 

[Brians356]

What are those stacked grey shims made of?
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[rwj]

View attachment 1282882

Do you remove the alignment jack bolts after tightening the main hold down bolts and reverifying alignment?

 

[jackieschmidt]

Do you remove the alignment jack bolts after tightening the main hold down bolts and reverifying alignment?

Yes. All of those are loose now, the shipyard will remove them and smooth out the surfaces with hand grinders.

The shims are stainless steel.

More times than not the reduction gear and engines will be installed on poured chocks rather than shims. In fact, many reduction gear manufacturers will not allow shims, they prefer the gears to be set with some type of epoxy chocking compound such as Chockfast Orange.

Chockfast Orange - ITW Performance Polymers

100% effective bearing underneath supported equipment | Developed as a chocking or grouting compound for use under marine main propulsion machinery in depths of ½ to 4 (12mm to 100mm)

itwperformancepolymers.com

This reduction gear is a TwinDisc 5600. Twin Disc allows shims in installations, and the customer who this boat belongs to prefers shims.

 

[Sniperhandle]

Your guys run like a well oiled machine, I've got to give you "PROPS"

 

[Sniperhandle]

Would Chockfast Orange be a good bedding compound for rifles?

 

[jackieschmidt]

Would Chockfast Orange be a good bedding compound for rifles?

No. It is a total liquid and is designed to fill every little void, nook, or cranny in the space between the foundation and the piece of equipment As you pour it.

 

[Brians356]

No. It is a total liquid and is designed to fill every little void, nook, or cranny in the space between the foundation and the piece of equipment As you pour it.

How do you contain such a liquid in application?
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