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Stone Age Machine Work……..

jackieschmidt

Gold $$ Contributor
In today’s whiz bang world of CAD/CNC Machining, there are still operations that have to be performed basically in the same manner as they were 75 years ago. I am doing one now.

One of our customers just installed two new Tier 4 Caterpillar Engines in one of their boats, and after the engines are aligned, they need a Body Fit Bolt installed at the aft end of each mounting rail.

Since space is limited, I have to design and build a set up capable of drilling and reaming a precision 1” diameter hole through 4 inches of steel.

As you can see, it’s all in the setup. I’m using a #3 Ingersal Rand PneumaticIMG_0196.jpegIMG_0194.jpeg Corner Drill in a rather simple attachment that is simply tack welded to the foundation. When you are finished with a hole, you just grind the tacks away and move to the next.

As with most jobs like this, the biggest hurdle is simply figuring out a way to do it within the allotted space and knowing how to put together a simple but efficient set up.
 
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I know exactly what that is like… my last job included maintaining metal forming equipment that was nearing 50 years in use. Many journals had to be restored to maintain alignment and bearing fits. Doing so required some creative in-place welding and machining practices... you do what ya gotta do!
 
Retro-fitting older equipment is always a challenge. Many machines that have been making money for companies were made before computers and CNC equipment did the work. That means hand building and hand repairing.
That is the main reason skilled trades are in such demand today.
Nice job Jackie!
 
In today’s whiz bang world of CAD/CNC Machining, there are still operations that have to be performed basically in the same manner as they were 75 years ago. I am doing one now.

One of our customers just installed two new Tier 4 Caterpillar Engines in one of their boats, and after the engines are aligned, they need a Body Fit Bolt installed at the aft end of each mounting rail.

Since space is limited, I have to design and build a set up capable of drilling and reaming a precision 1” diameter hole through 4 inches of steel.

As you can see, it’s all in the setup. I’m using a #3 Ingersal Rand PneumaticView attachment 1602344View attachment 1602345 Corner Drill in a rather simple attachment that is simply tack welded to the foundation. When you are finished with a hole, you just grind the tacks away and move to the next.

As with most jobs like this, the biggest hurdle is simply figuring out a way to do it within the allotted space and knowing how to put together a simple but efficient set up.
How do you tack weld precisely enough?
 
I know basically nothing about boats. Is it possble to easily explain what a " Corner Fit Bolt" is, or does?
 
I know basically nothing about boats. Is it possble to easily explain what a " Corner Fit Bolt" is, or does?
It’s a “body fit bolt”. Basically, you drill and ream the hole, then machine a bolt that has a body that has about .001 interference fit. You put the bolt in liquid nitrogen for sbout 15 minutes, then slip it.

The purpose of the body fit bolts is to keep the engine from shifting any on the foundation through normal running cycles.

The reduction gear, which also takes the propeller thrust, has body fit bolts that serve the same purpose.

Here I am a couple of weeks ago drilling a Reduction Gear mounting foot for body fit bolts in a new installation Using a similar setup.IMG_0026.jpeg
 
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You might be right about the drill. We have three of these #3 motors, two #4’s, and a #5. About the only thing that ever wears out in them are the air motor vanes, which I make myself.
I'm sure you can hear about as good as me too! I worked in heavy equipment shops and Fab shops, Some air tools are deafening.
 
It’s a “body fit bolt”. Basically, you drill and ream the hole, then machine a bolt that has a body that has about .001 interference fit. You put the bolt in liquid nitrogen for sbout 15 minutes, then slip it.

The purpose of the body fit bolts is to keep the engine from shifting any on the foundation through normal running cycles.

The reduction gear, which aldo takes the propeller thrust, has body fit bolts that serve the same purpose.

Here I am a couple of weeks ago drilling a Reduction Gear mounting foot for body fit bolts in a new installation Using a similar setup.
Thank You for explaining the "Body Fit Bolt". I'm sorry I couldn't ask the correct name.
 
Pneumatic is a bit different! Could you tack a plate in position and use a mag drill? Some have MT taper and pretty long stroke.
 
Pneumatic is a bit different! Could you tack a plate in position and use a mag drill? Some have MT taper and pretty long stroke.
I have Two mag base drills, they have to much play in the dovetail, and are limited to about a 1” hole.
That, and you simply can’t get it into the space where you have to drill.
That’s what is nice about the big pneumatic corner drills. You can get into tight spots with a lot of power.
 
It’s a “body fit bolt”. Basically, you drill and ream the hole, then machine a bolt that has a body that has about .001 interference fit. You put the bolt in liquid nitrogen for sbout 15 minutes, then slip it.

The purpose of the body fit bolts is to keep the engine from shifting any on the foundation through normal running cycles.

The reduction gear, which aldo takes the propeller thrust, has body fit bolts that serve the same purpose.

Here I am a couple of weeks ago drilling a Reduction Gear mounting foot for body fit bolts in a new installation Using a similar setup.View attachment 1602447
Jackie,
I would imagine removing that in interference fit bolt would be an interesting job. Do u drill em down the center to induce a collapse?
 

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