Machining large marine bearing.

jackie schmidt

jackie schmidt

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Jackie was your knowledge passed down from your Father and his from his Father.

Thanks for sharing I find it very interesting.
JLouis
 
Louis.J said:
Jackie was your knowledge passed down from your Father and his from his Father.

Thanks for sharing I find it very interesting.
JLouis
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My Dad never knew his father, (a German immigrant). He was passed away when my Dad was 5 years old.

I learned the basics from him. He and my next oldest brother died in 1985 and 1986. My oldest brother, my younger brother, and I have built our business into what it is now.

None of us have any "formal" training. We all sorta of learned as we went.......and we keep on learning as machine shop practice evolves, and our major customer base advances.
 
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Thank you Jackie I did not mean to bring up a bad time in the past and I do highly appreciate you sharing it. I must add that I have never seen a cleaner more organized shop in my life it is absoultly spotless. It alone indicates to me the quality of the work you are turning out, the pride of what you own and also the success achieved and I was looking real close. Not something one sees very often in a typical shop environment and I was quite amazed by it all when I clicked on the picture of the prop being installed.

JLouis
 
Louis.J said:
Thank you Jackie I did not mean to bring up a bad time in the past and I do highly appreciate you sharing it. I must add that I have never seen a cleaner more organized shop in my life it is absoultly spotless. It alone indicates to me the quality of the work you are turning out, the pride of what you own and also the success achieved and I was looking real close. Not something one sees very often in a typical shop environment and I was quite amazed by it all when I clicked on the picture of the prop being installed.

JLouis
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It can get pretty cluttered. Here is one of our 28 ft lathes with various forgings and bars ready to be machined along with other machines.

We have 4 main buildings, and all are literally packed full of various machines; lathes, large and small, various mills and boring mills, drill press, shapers, slotters, cranes, and all the tools to make it all work.

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Thanks again Jackie I truly am speechless and totaly intrigued and I don't know what else to say other than thank you so very much for sharing. It is truly highly appreciated on my behalf and a lifestyle I have been ignorant of yet a very special one indeed.

Yours Sincerely
John Louis
 
Louis.J said:
Thanks again Jackie I truly am speechless and totaly intrigued and I don't know what else to say other than thank you so very much for sharing. It is truly highly appreciated on my behalf and a lifestyle I have been ignorant of yet a very special one indeed.

Yours Sincerely
John Louis
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Louis, due to the way the Machine Shop Industry has evolved over the past 20 years, Shops such as mine are becoming an anomaly. The CAD/CAM revolution in machining techniques has rendered the manual machinist a dying breed, even at the Job Shop level.

But there are still multitudes of shops scattered out that serve what I guess you could call "niche" industries, where the work that comes in simply doesn't lend its self to CNC controled equipment. Many of these shops service a particular industry, ours happens to be the Marine Industry, particularly the Inland Marine and Shipyard fields, where much of the work that comes through the door is repair, and on equipment that I would call in "less than pristine condition".

For your own info, this is typical of the size Push Boat that we do the underwater running gear for. This is a 3600 HP 92 ft long vessel that we did all of the shafting, rudders, steering system, bearings and in place machine work on a year or so ago.

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Jackie,

Tell us about the tolerances you have to hold on these long and/or large diameter parts you machine, such as the bushing in the first picture.

I know the tolerances vary with part and application, so it's hard to say "+/- point-whatever", but being completely unfamiliar with big work like you do, I have no idea what kind of wiggle room you have to work with.

Justin
 
Tha bearing presses in a housing on the boat, called either a Strut or a Stern Tube. If it is a new, fresh bored hole, we shoot for .003 inch interference, or press fit. That will require about 70 to 80 tons to install. It has three steps, so they can actually slip the bearing in 2/3 of the way before it has to press.

So I have about a +.002 -.000 tolerance to play with. Too tight, and their 100 ton hollow ram will not push it in, too loose, and it might spin or allow water to infiltrate the fit, and 4 years later, the Strut is ruined.

On big shafts, they have to be "fully machined and truly straight". We don't want anything running more than .003 or so anywhere on the shaft, regardless of the size. This is especially critical on thecoupling end that attaches to the reduction gear.

This is a 12 inch diameter 30 ft long prop shaft we are repairing. When we get through, we can place it on centers with a steady rest in the middle, and expect no more than .002/.003 inch runnout any where on it. The last picture is the coupling that goes on the shaft that attaches it to the reduction gear.
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Jackie thank you again so very much for sharing the work you and your shop does it is simply extremely intriguing to me. If you do not mind me asking how many shafts do you heat straighten / the only process I am aware of in lieu of replacing. If I may also ask are their any younger family members to carry on what I would consider a lost art that can only be passed down by not having any other means of learning your entire trade that I am aware of. And one more if you do not mind do the props have to be lapped onto the taper.


Thanks for the picture of the pusher it does give me a clearer picture of what you work on.
JLouis
 
We do not heat straighten shafts. We have "straightening rigs" of our own design and make that use Hydraulic pressure. We have four, a 150 ton, a 250 ton, 500 ton, and a 750 ton to handle just about any size shaft.

The picture is of our 150 ton rig. You can see how we use it, the arms are adjustable, we can put what I call "precision tonnage" at any point on the shaft. The first picture is the 750 ton rig in it's storage cradle. That rig its self weighs about 2500 lbs.

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As for "lapping" the tapers o the propellars, we hand grind them to fit. The prop shops warp the bores when they have to do any serious blade work or re-pitching of the propeller's blades. Go back to the picture of the shaft. You can see the Prussian Blue that is use to get the impression as we take the propellar on and off. It's very labor intensive, but as with all things we do, we have special tools and set up that allows us to be very efficient at this.
 

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Double WOW on all of it

Jackie, how do you keep those 28 foot lathe beds aligned? Or is it a one time setup?
 
adamsgt said:
Jackie, how do you keep those 28 foot lathe beds aligned? Or is it a one time setup?
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All of our large machines sits on an individule piered concrete pad anywhere from 24 inches to 48 inches thick. Here is our big Lucas Boring Mill, notice the difference in the floor. The floor is just 8 inches, the pad is 36 inches thick.

The lathes are the same way, and they stay reasonably level. We check them periodically with a Starret Transit and levels.

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The other pic is looking from the back of our 44 ft LeBlond lathe.
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Jackie,

With some of the lengths and diameters you deal with, it would seem that a single cutting pass in a lathe could take hours. True?

If so, what do you think your longest pass time-wise was?

Justin
 
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