Building a Big Engine

[fredrosse]

I am participating in the building of a rather large new steamboat engine, possibly the largest reciprocating steam engine being built in this century, at about 12 feet overall height. This is a slow speed American Walking Beam Engine for a sidewheeler. The steam chest tubes (for piston valves) are too large for my lathe at a little over 44 inches in length, and require relatively simple turning/boring work in mild steel.

I make "old school" drawings, but every machine shop I have contacted can not accept such drawings, they need Computer Aided Design (CAD) files, where their computer controlled machine tools can be setup make the parts without an "old school" machinist looking at a drawing and making the parts. How the world changes the way things are done! I would like to have any suggestions as to how I might expedite having these steam chest tubes, as well as the piston valve spools, and the thermal sleeves, made.

Thanks in advance for any help.

[fredrosse]

Detail drawing for the steam chest tubes,two are required, made from ordinary steel pipe or mechanical tubing. These drawings are made in CorelDraw, and are also available as PDF files.

[TahoeSteam]

I'd love to hear/see more details! 13-1/4"x27" is quite the engine!

This might help you if you've got the space:

http://vintagemachinery.org/classifieds ... x?id=19890

A look on craigslist and there's tons of large manal lathes for sale for incredible prices. If you have the space of course...

[fredrosse]

Thanks Wesley for your suggestion, but at 74 years of age, with 4 smaller lathes in my workshop, buying another large machine is not an option for me. I'm a bit too old to be moving such machines, let alone the steel stock to make the tube is too heavy for me to lift!

These parts need to be made by a commercial machine shop, but all that I have contacted are not interested. One machine shop offered to quote the work if I paid $1000 to have one of their employees make the drawing for the steam chest tube in their CAD software, then their software could generate a price to make the part. I don't want to pick up that option, I was expecting a price of less than $1000 to make these tubes, but at $1000 just to get a price estimate, no thanks.

Picture is about a year old, showing progress to that date:

[TahoeSteam]

That is impressive! Is it going to be in an actual boat, or a museum exhibit?

Have you see these folks?:

https://www.emachineshop.com/

[fredrosse]

The original engines used poppet valves, and the owner of this engine wants the Marshall-Bremme valve gear that is used on my sidewheeler, with piston valves that are more appropriate for his size engine. Everything on this engine is for real functioning, so I guess he will get to buying (or building) a hull, and a hull for this engine will need to be near 100 feet long.

[DetroiTug]

Hi Fred,

You need a lathe with about a 10 foot bed to do those, line bore.

The only people I know that are capable and reasonable and would most likely take the job is Thiry machine in Dearborn. That's duck soup for them. They have giant Atkinson lathes, bullards, vertical lathes etc, they made parts for ww2 effort.

In business for 84 years. They don't need cad models, no one that knows what they're doing does for manual lathe work. A rough sketch is likely fine. As Sergeant Friday used to say ''just the facts, Miss''

Thiry machine
6500 Chase RdDearborn, MI 48126
(313) 584-3730

[DetroiTug]

Fred, a friend of mine up in Manitowoc, Wi. is very knowledgeable about building and restoring these large historic engines and steam history in general, he's a retired curator from the Henry Ford museum and responsible for some of the large steam engines they have on display there. He knows where to get a lot of difficult to source parts and castings etc. Matter of fact,he has a great replicated stilling column for a plant about that size.

If interested, I will ask him if he's interested in helping?

[PeteThePen1]

Hi Folks

This sounds an interesting thread and the original issue of not having CAD drawings sounds to be as good as overcome. However, just in case it might be useful to you, it is possible to find free online sites that will convert files. Drawing files in Corel format or PDF should be no problem and can be turned into .DXF files. Once in that format I am sure that there are plenty of proper engineers on this site who would be willing to load up the CAD file and check that everything that should be there is there.

My own experience with these conversion sites is that one has to 'shop around'. The PDF's sent to us by an architect we employed who refused to send us the CAD files were beautifully converted by one site. When used with another drawing PDF from a different source the result was dire.

Here are a few, but with no recommendations. All will convert from Corel files they claim:

Zamzar - https://www.zamzar.com/convert/pdf-to-dxf/
Cloud Convert - https://cloudconvert.com/pdf-to-dxf
Any Conv - https://anyconv.com/pdf-to-dxf-converter/
Convertio - https://convertio.co/cdr-dxf/

Beware that some sites like to add a watermark to your drawing, but I forgot to make a note of which ones... Sorry.

Hope this is useful.

Best wishes for the New Year to you all.

Pete

UPDATE: I have found and tested Filestar https://filestar.com/. This is a download to which one needs to sign up, but one can choose the free version which is for low usage (10 file conversions per month max). I have tried it with CAD files that I have received in PDF format and it has recreated the CAD format very well. Text was somewhat problematic, but that is the same sort of issue I get when my TurboCAD 21 reads AutoCAD files. I have tested it with .JPEG and .PNG files including the first one shown in this thread and the result is poor. This suggests that it is good with a vector graphics source (which I think is true for Corel Draw), but not good with a pure pixel format such as JPEG.

Regards

Pete

[DetroiTug]

Pete,

The problem with converting from pictorial format to engineering drawing format is different levels of precision. The Corel drawings exported in DXF format perhaps, once taken into a CAD program, there are many misalignment of entities and some that don't actually meet, only get close; fine for visual representation, but unacceptable for Cad programs that work in micron level accuracy. Corel, as far as I know does not use true arcs like a cad program does, it's arcs and splines of multi segmented lines. In the CAD program this can work only if they are precisely chained together, and begin and end in the proper orientation. Else there is a a lot of start at A go to C come back to B, then go to E come back to D, although usually much worse. If it's programmed in a CAM program, there will be many Z retracts as the CAM will not machine across dead space in the drawing, it will retract, move over, extend Z and then resume on the next entity. Not a very efficient or safe machine operation. Some trickery can be used like reducing the accuracy level of the cad program with improved but imperfect results. Not worth the hassle or loss of precision for some entities.

That is why machine shops refuse Corel drawings and PDF's.

The JPEG, BMP to Vector converters suffer the same conundrum. The precision is key to the best result, but none will be perfect. They create vectors by averaging shading of pixelation color and how tight the pixelation is. When I'm replicating a company logo and do not have the original art in a CAD format (which is always), only a JPG etc, I use a bmp to vector converter and then export the less than good lines to a CAD window. Then using a different color line, I simply redraw over the top, trace, new lines using splines, arcs and lines, once complete, I select all the original lines and delete them. What's left are clean precision lines that can be taken to a CAM program for Gcode generation.

The remedy to all that above is purchase an inexpensive CAD/CAM program and learn it, then .CAD, .STL and .DXF etc can be exported in shareable friendly formats that many different CAD softwares can readily read and use.

https://www.dolphincadcam.com/ they are based in the UK

There's no shortcuts