Author Topic: Forest 1889 6 cyl Marine Engine  (Read 6847 times)

Offline Kim

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Re: Forest 1889 6 cyl Marine Engine
« Reply #15 on: May 18, 2021, 05:19:14 PM »
Embedding the nuts like that is a neat idea!  I'm not much up on 3D printing, but will likely get into it someday.  This is all very fascinating!

Kim

Offline gbritnell

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Re: Forest 1889 6 cyl Marine Engine
« Reply #16 on: May 18, 2021, 05:33:24 PM »
Hi Maury,
Good to see you're back. I really enjoy the unique engines you come up with. I'm following along on this one. Looks like it will be very interesting.
gbritnell
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Offline Roger B

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Re: Forest 1889 6 cyl Marine Engine
« Reply #17 on: May 18, 2021, 07:57:37 PM »
Fascinating 3d printing  :)  :headscratch:  :wine1: but currently way beyond me  :old:
Best regards

Roger

Offline Craig DeShong

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Re: Forest 1889 6 cyl Marine Engine
« Reply #18 on: May 18, 2021, 10:04:18 PM »
Hi Maury

We talked a while back on the phone when I was inquiring on the availability of your Forest 4 cyl. engine.  Great to see you working on a 6! I'll be watching; and my interest in the forest design hasn't waned since we talked.  :popcorn: :popcorn: :popcorn:
Craig
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Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #19 on: May 18, 2021, 11:09:54 PM »
Kim, Embedding the nuts is not my idea, but I'm using
it as a best alternative to making my own Press-In inserts.
I haven't tried, but I think it would be difficult to knurl a 1/8"
rod, and then drill & tap it 2-56 a bunch of times.
George, I was never gone, thanks for tuning in. Same for Roger, I hope
everyone is going to enjoy the printing way to build models. If
I still had access to good iron foundry, this engine would be in
castings.
Roger, I hope you can pony up and take my patterns and continue the
Forest 1888. I believe there are still folks out there who want to
build engines with castings. This is the most authentic way to realize
these old engines.

Next will be the base. it's a 2 day and 9 hour print.

maury
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Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #20 on: May 19, 2021, 02:58:25 PM »
OK, it's time to brave a really long print. This is a first for me, 2 days 9 hours. I will be making the base for the engine. There are a lot of overhang features, so extensive support will be needed. There are many options in the slicing process, and there is a lot of variability in print time, and support given. I studied these options exhaustively and have chosen the option where the slicer generates a tree structure.  As the print progresses, you will see these wierd structures as they grow into a tree under the overhang. At the top of the tree, a grid is generated as the final support level. There is a 1 layer gap between the grid and the actual part geometry. So as the part geometry sags down to the grid, it is supported. Since there is minimal connection between the support and the part geometry, it is fairly easy to remove. However, the underside of the geometry is somewhat rough compared to the tops of the part.

As with all 3D prints, the first layer is critical. If it doesn't adhere to the build plate and stay flat, the print will fail. I have found that different brands of filament behave differently, and different colors within the same brand behave a bit differently. The particular filament I'm using extrudes quite nicely, but it's build plate adhesion is a bit of a problem. I have to use a layer of glue on the build plate for this particular filament.

Day 1 progress:

maury
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Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #21 on: May 20, 2021, 05:20:48 PM »
Day 2 Progress:

maury
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Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #22 on: May 21, 2021, 02:55:50 PM »
Day 3 Progress -or not-

I woke up on day 3 and checked my printer only to find out the nozzle had clogged. The printer was still running, but no plastic was being extruded. What to do? I didn't have enough filament left on the spool to start it over, and more immediate, the dead would have to be cleaned out.

I cleaned the hot end and replaced the nozzle, but the filament had melted up into the Bowden tube, and I had to replace that too. not that bad, but a big interruption.

What to do about the engine base? it turns out the top surface last printed was clean and smooth, so I decided to take a temporary short cut. I will lightly sand the top and measure it. Then go back into Solidworks and cut the part at the last printed plane. Si I will make a new part starting at this plane and glue it on the lower part. I don't know if this will work well, and I will probably go back and make another base at some time. I think it will be almost impossible to make an invisible glue line.

maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline Kim

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Re: Forest 1889 6 cyl Marine Engine
« Reply #23 on: May 21, 2021, 05:55:21 PM »
That's frustrating!   Two full days into the print and something happens!  :wallbang:
I'm not a 3D printer guy (yet) so I don't have any words of wisdom to offer.  Just some commiseration.

But this sounds like a reasonable way forward, and as you said, you can always try again if you choose to.

Kim


Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #24 on: May 22, 2021, 03:42:36 PM »
Kim, thanks for the comments.

The base has been cleaned up a bit, and I glued it together with epoxy.The match is close, but not quite right on. For now it's good enough to proceed... there is no telling what I will run into with the small parts on the heads.

maury
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Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #25 on: May 24, 2021, 02:42:12 PM »
With the base printed, I thought I'd start making parts for the crank shaft and it's bearings.
I am able to print the main bearings in the engine color, change filament, and print the oilers all in one part.

i will print the con rod bearings all in one color, as the oilers begin at a lower level from the top of the bearing block.
There are small alignment tabs on the top of the rod bearings to align the con rods. The con rod bearings were a little rough inside, and a bit undersized. A while back I bought a set of adjustable reamers, so this seems to be the perfect use for them.
the bearing cleaned up nicely and gave a good fit to the dim I needed.

maury
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Offline mnay

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Re: Forest 1889 6 cyl Marine Engine
« Reply #26 on: May 25, 2021, 04:35:52 PM »
Maury,
I have not had the courage to make that large of a 3 d print.  What do you use on your build plate to get it to stick?
I use hair spray on a glass plate and it does ok.
thanks,
Mike

Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #27 on: May 25, 2021, 04:50:04 PM »
Mnay, thanks for the response. I use gorilla glue stick. It may be a bit overkill, but it was the only glue stick I could find on the shopping outing when I needed it. The burgandy filament I'm using is matter hackers professional filament. It makes decent parts, but it is the only filament I've has problems sticking to the bed plate. With the thin support I need, sticking on the initial layers is obviously critical. I've had do do a few restarts with this filament, but I like the color.

A little progress, the crank parts and the crank assembly with the rod bearings is shown below.

maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

Offline ddmckee54

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Re: Forest 1889 6 cyl Marine Engine
« Reply #28 on: May 25, 2021, 08:18:04 PM »
Maury:

For embedded fasteners in a 3D print, try something like these.
https://www.amazon.com/initeq-2-56-Threaded-Inserts-Printing/dp/B07BB22SQS
I believe that you mentioned you were using 2-56 fasteners at some point.

You just print the proper size hole and then embed the fastener using a soldering iron, or similar heat source.  They work like a charm and are much easier than trying to design an internal pocket, pausing the print at the right time, and inserting a nut.

I've found that splitting large parts into several smaller parts works best for me.  Losing a 12 hour print 9 hours into the print hurts a lot less than losing a 57 hour print 40 hours into it.  It also gives you the option of flipping the smaller part over on the print bed, eliminating the overhang and the need for support.  It might also make it possible to bolt, and glue, the parts together.  Personally I don't have any problems with a belt AND suspenders.

Don

P.S. I wonder what a bead blasted 3D print would look like?  Kind of like vapor smoothing in reverse.
« Last Edit: May 25, 2021, 08:22:21 PM by ddmckee54 »

Offline maury

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Re: Forest 1889 6 cyl Marine Engine
« Reply #29 on: May 25, 2021, 09:47:23 PM »
Don, thank you so much for the link. I searched everywhere for just this kind of insert, but it didn't pop up in my searches. Just what I need. I'm going to order the short and long ones. Maybe with a bit more poking around, I can find 1-72 and 3-48 as well.

Thanks again,
maury
"The trouble with socialism is that you eventually run out of other people's money."... Margaret Thatcher

 

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