A Little Bit Different Machine Work

[jackieschmidt]

One of our customers, G&H Towing, has had one of their big 5000 HP Harbor Tugs in the shipyard for a while, one of the last operations in the refit is the reduction gear alignment To the prop shaft, and then the engine to the reduction gear.

The gears will be set in Chockfast Orange. That means the end hold down holes on each foundation foot must be drilled, reamed, and have a body fit bolt fit.

Here are some pictures of the various operations down in the engine room and in the shop. This tends to be physical, dirty work, but we do quite a bit of it. As you can see, just figuring out how to get down in there, attach the equipment as needed and drill and ream this size precision hole takes a little bit of thought.

I made a setup to drill and ream the holes in place using a big #4 Ingersol Air Drill, , then machined the body fit bolts to fit around .001 tight in each hole. To install the bolts, we freeze them in liquid nitrogen.

After the reduction gears are pulled down and finalized, they will align the 16 cylinder 645EMD to the gear. We will then have to drill and ream two holes in each rear foot for body fit bolts.

 

[jackieschmidt]

 

[jackieschmidt]

 

[caihlen]

Pretty cool Jackie.

 

[Shooter13]

In the 9th pic down looks like a blower from a car engine! You sure like getting your hand dirty! Interesting stuff.

 

[VA_XTC_Shooter]

That's some real work right there! nice

 

[Gene Beggs]

Jackie, thanks for posting the photos and information about your work with marine machining etc. It's fascinating !

Gene Beggs

 

[BoydAllen]

Interesting stuff. Thanks for sharing.

 

[snert]

And I thought inletting and bedding an action was tough. WOW

 

[Steve Blair]

In the 9th pic down looks like a blower from a car engine! You sure like getting your hand dirty! Interesting stuff.

It's the other way around. All those early GM/Detroit Diesel blowers came from diesel engines. Hot rodders took the 4-71, 6-71 and other models and adapted them to gasoline engines.

 

[hoz53]

One of our customers, G&H Towing, has had one of their big 5000 HP Harbor Tugs in the shipyard for a while, one of the last operations in the refit is the reduction gear alignment To the prop shaft, and then the engine to the reduction gear.

The gears will be set in Chockfast Orange. That means the end hold down holes on each foundation foot must be drilled, reamed, and have a body fit bolt fit.

Here are some pictures of the various operations down in the engine room and in the shop. This tends to be physical, dirty work, but we do quite a bit of it. As you can see, just figuring out how to get down in there, attach the equipment as needed and drill and ream this size precision hole takes a little bit of thought.

I made a setup to drill and ream the holes in place using a big #4 Ingersol Air Drill, , then machined the body fit bolts to fit around .001 tight in each hole. To install the bolts, we freeze them in liquid nitrogen.

After the reduction gears are pulled down and finalized, they will align the 16 cylinder 645EMD to the gear. We will then have to drill and ream two holes in each rear foot for body fit bolts.
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interesting stuff/ thank you

 

[Chiquita]

Why do you freeze the bolts in liquid nitrogen?

 

[jackieschmidt]

Why do you freeze the bolts in liquid nitrogen?

As you can see, it is pretty tight working down in that hole. The body fit bolts have .001 interference fit, which is tight. Pounding them in with an 8 pound hammer is a real pain. So, we just soak them in liquid nitrogen for about 15 minutes and slip them in.

 

[jdh47]

Interesting machining ops. I guess you have to drill out the bolts if they're ever removed. That's some tough work.

 

[acloco]

When I worked in the automotive engine machine shop, we tried to save the block sleeving jobs until winter.

Bore the block to correct size for sleeve, let sit over night in the shop. Also let the new sleeve sit overnight, outside, in Jan/Feb/March.......in Havre, Montana!

 

[jackieschmidt]

Interesting machining ops. I guess you have to drill out the bolts if they're ever removed. That's some tough work.

Not really, because you can get a good hit on them from the top, as they are placed in from the bottom. Granted, it does take some effort, but for the bolts to do their job, they have to be rather tight.

The purpose of the Body Fit Bolts in applications where ChockFast is used is to keep the reduction gear firmly in place under normal working conditions. The reduction gear is what takes the thrust of the propeller.

 

[Chiquita]

As you can see, it is pretty tight working down in that hole. The body fit bolts have .001 interference fit, which is tight. Pounding them in with an 8 pound hammer is a real pain. So, we just soak them in liquid nitrogen for about 15 minutes and slip them in.

Soaking them into nitrogen shrinks them a tiny bit? Or what does it do?

 

[sdean]

It's the other way around. All those early GM/Detroit Diesel blowers came from diesel engines. Hot rodders took the 4-71, 6-71 and other models and adapted them to gasoline engines.

That EMD blower will swallow a 671 blower.

 

[jackieschmidt]

Soaking them into nitrogen shrinks them a tiny bit? Or what does it do?

That’s it. The bolt will shrink approx .003 in the liquid nitrogen.

 

[rwj]

That’s it. The bolt will shrink approx .003 in the liquid nitrogen.

Beware of the nil ductility material property that can result in brittle failure when steel is exposed to cryogenic temperatures!