Forest 1889 6 cyl Marine Engine

[maury]

Folks, there is a bit of a delay in the work on the Dickson. so I thought I'd spend a few days
working on a back burner design project I've been wanting to do for some time. I am really
fascinated by the work Fernand Forest did on pioneering internal combustion engines. As
some of you know, I scaled the 1888 4 cylinder marine engine and offered a casting kit of it
several years ago.  In "Les Bateaux Automobiles..." Fernand Forest describes a 6 cylinder
marine engine. That is my new design project.

So far, I have the basic outline for the lower part of the engine modeled. There are still many
details to be covered, but I wanted to find out how well I would be able to do with only a small
picture of the original drawings as shown in the book. Luckily, there is a front and side view with
part of the front view sectioned off. The drawing is clear enough for me to measure with a caliper
and scale the parts.Unfortunately, none of the dimensions are legible. I also have a picture of
the engine installed in a boat. Not a whole lot to work from. As best I know, there are no surviving
examples of this engine.

There are several pages of text associated with the engine in the book, but it's in french. If there
is someone out there who would be willing to translate those pages, I'd like the help.

maury

[Admiral_dk]

If it is on the web - use Google to translate 

[kvom]

Email me the text and I'll translate. 

[maury]

Guys, thanks for tuning in.
KVOM. thanks for the offer. There is no electronic copy that I know of, I can scan images of the pages and email them to you. If you are still interested, let me know.

THanks,
maury

[kvom]

That's what I expected.  Send them.

[maury]

Well I know this is an old thread, but I want to ressurect this project. I picked up an Ender 5 3D printer this past Christmas, and have been playing around with it. I have enough experience on it now to build an engine-so I believe.

 Over the years, I have also almost completed the Forest 1889 6 cylinder CAD design. Just have a few of the small parts to go. It's been a long time coming, but I have been wanting to build this engine since I completed the Forest 1888 4 cylinder. I will be doing this build on my 3D printer. We'll see how it goes.

maury

[Dave Otto]

Hi Maury

Are you planning to use the printer for making patterns?

Dave

[maury]

Dave, About a year or so ago I started making the base pattern on my CNC. I have decided this part is too complex to cast for the purpose of making only one part. So, I am planning to do the build on my 3D printer.

Another reason, I don't have an iron foundry any more, so there is little point in doing castings. I would prefer castings, but I regard aluminum to be no better than plastic.

If anyone is interested in doing castings for this engine, I would be happy to give them the design, and to help where ever possible.

maury

[maury]

3D printing is new to me, so I'll have to do some background work and decision making to start with.

First off, I need to figure out what fastners would be good for this project. After thinking about some, and looking at a few other printed engines I decided to use holes and printed pins for alignment, and bolts for the big parts. I have seen a project that used embedded nuts in the plastic instead of tapped holes. I'm going to use this idea.

Also, holes and pins are a bit tricky in 3D. The printer has a line width of .4mm and a line height of .2mm or greater, using a .4mm nozzle. This isn't the best accuracy compared to what our metal working machines have.

I have done a number of test patterns with some hole sizes and printed pegs with the same diameter as the holes. I have also done a test pattern with embedded nuts of various dimensions to determine what works well. Using this information, I can then adjust the geometry of my model to get the correct hole sizes for the final printed part.

Playing around with this I have also found the holes are a bit fuzzy, so I use a pin vise with a drill to clean out the holes after printing. This gives a nice fit.

maury

[tvoght]

I'm watching with interest, Maury. I appreciate your methodical testing to refine techinique.  --Tim

[maury]

Dave, and Tim, thanks for tuning in.

Another possible project issue is the gears. This model uses a 1:1 set of gears driven off the crank shaft. They drive a lee shaft setup that extends to the engine heads, where a set of 1:2 gears drive the cam shaft. There is also a set of miter gears on the pinion of this second set that spins the governor.

I played around in CAD, Gearotics, and the 3D Cura slicer software for some time to determine whether I would be able to actually print the gears in the sizes I would need. I can make the spur gears on my gear hobber in metal, but not the miter gears.

After several tries, I found I would be able to make useful gears at 28DP. These would make pairs that will work well , but the pitch circles are a bit off from what I need. In Cura, I can scale parts up and down, and scaling a few % I was able to get the dimensions I need.

Here is a Pic of some of the original results.

maury

[maury]

Moving along, I printed the cylinder liners in anticipation of doing the water jacket parts. I wanted to start out making some parts with shorter print times, as I am using a new filament, and I wanted to try out the embedded nuts.

The water jacket parts needed support to print , and that always involves a bit of clean up after the print.

maury

[maury]

I thought I'd try a longer print. The columns take about 8 hours to print, and thy also have embedded nuts.  bit of a bigger challenge. There is some support required for this part also, and will require a bit of cleanup after the print. The Pics show the progress.
maury

[Dave Otto]

That looks good Maury!

So you put a pause in the program that allows you to place the nuts, then continue? I think our Stratasys machines here at work will do that but I have never tried it.
I have used a number of Heli-Coils in printed parts and that is also another good option for stronger threads.

Dave

[maury]

Dave, thanks for the comment.
yes, the Cura slicer allows various macros to be included in the G-Code. The pause macro is set up to retract the print head, park it at a programmable destination, and resume with a button click.

I initially wanted to use something like heli-coils, but I was unable to find them in 2-56. I could get small metric ones, but then I was unable to find same size metric hex bolts... Thus the embedded nuts. There may be places on the heads of this model where I'll need 1-72 or even 0-80. That being the case, I may just need to use alignment pins and glue.. yuk...

I haven't tried to tap these small holes in plastic, but I suspect it will not end well.

maury