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Thread: Atlantic Make and Break Fabrication Project @MIT

  1. #71
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Our semester wrapped up a few weeks ago, and commencement was today. The Atlantic project is now in a holding pattern, pending some summer work, and will pick up again in the fall. Summarizing the state of affairs:
    1. The ignition system works on a test setup, complete with coil.
    2. The water pump is complete and functions
    3. The crankshaft is complete, along with the eccentric and eccentric strap.
    4. We purchased a really nice wood lathe, so our students don't have to trek to the Hobby Shop. Patterns for the manifold, waterjacket core mold, and cylinder are in process. The cylinder bore core mold pattern is done.
    5. We will try to use the base and flange that Lunenburg gave us.
    6. The piston and connecting rod are being finished machined.
    7. The flywheel pattern is essentially done, and a local foundry will cast it for us, since we are limited to approximately 80# pour at MIT.

    During an end-of-semester event, the students displayed their work. Here are some pictures of the test rig showing the crank, ignition, and water pump (and various items in the foreground)







    Although we didn't complete an engine this term, no doubt every student learned about pattern-making, metallurgy, machining, casting, history, and engines. We also developed a terrific relationship with the folks from the Lunenburg Foundry, and have to thank Peter and John Kinley, and David and Laura Allen. Their assistance and support has been crucial. All in all, the class was a success and we look forward to continuing in the fall. More anon!

  2. #72
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Great thread, I have no doubt you'll all get this engine together.

    I've never had a go, but as you found, there are a few tricks to getting sand casting to work. What I'm curious about is, back in the day they just had sand, horsehair and spit, and were manufacturing these things by the dozen, presumably with a decent success rate.
    I would have expected the modern casting sand would be easier to work with and more forgiving, but it sounds like the shrinkage and short working time were a bit of a pain.
    Do you think the problems you had with the moulds for the piston had more to do with the sand, or draft angles and surface finish of the pattern?
    And is the sand with resin really intended for more automated casting processes, where working time perhaps isnt such an issue?

    Pete
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  3. #73
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Hi Pete.
    I'm no expert, but based on my observations, I say the difficulties could be attributed to a number of factors, most notably those things you described. Draft angles were fine, but the surface finishes didn't help. For the 3d printed parts, the pump and eccentric strap were acetone vapor polished, whereas the 3d printed piston pattern and piston core mold were sanded and primed. However, I think sanding and coating a nicely fabricated wood pattern yields much nicer finishes. Out printer is a Stratesys 1200es, and there other printers that produce finer surfaces.

    The bigger factor, I think, was related to the size and geometry of the core print. Had the various appendages been smaller, with generous fillets, I'm guessing the sand would not have sheared as easily.

    Part of the big teaching moment was for students to appreciate that these parts were produced by skilled and knowledgable people 100 years ago, without CAD, CNC machining, and 3d printing. I think they got that lesson. One great moment was when a student walked by a lathe and commented that the tailstock casting was amazing.

  4. #74
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Very cool.


    Kevin
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  5. #75
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    ...keeping the project alive....
    here are two short high speed (420 fps) videos of the ignition system. The crankshaft was driven by a lathe. Separately, we started the cylinder patterns and will be at a slow burn rate for the next few months.

  6. #76
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    and the other...
    Last edited by DoctorB; 11-01-2016 at 07:53 PM.

  7. #77
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I installed one of these engines but never saw how it all worked inside. Some ingeniously simple elements like the cam timing adjustment.

  8. #78
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    We installed a new Southwest 3-axis mill in the lab recently and gave it a whirl by making a test pattern (minus core prints) of the manifold. I used Ren shape for the test material. Students will now have the option of CAD/CAM pattern making along with woodworking and 3d printing. The various processes make for good pro/con conversations with students.
    We'll be thinking about the manifold core prints and core molds next.
    In other news, we are starting a Herreshoff steam engine...like I need another project...We're working with the Hart Nautical Collection and have a small group of students starting that spring term. It's a small recirculating engine used on one of the torpedo boats. More on that later.

  9. #79
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    All neat stuff! Thank you for the update on what is going on over there.
    This past summer I repaired the water jacket on my 5hp Acadia engine. It is a nice running engine now.

  10. #80
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I just came across this picture on the facebook page for the Make and Break Club of Lunenburg


    I believe these are the MIT students building the engine

  11. #81
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    Default Re: Atlantic Make and Break Fabrication Project @MIT



    Here is my Acadia if anyone is interested in seeing one of these running.

  12. #82
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Yep, that's Josh and Jarrod in the center. Instead of going to Cancun last spring break, they ventured to Nova Scotia to spend time with the Lunenburg Foundry and the Atlantic Fisheries Museum. Good for them.
    Josh and Jarrod were responsible for the crankshaft and ignition system. They graduated and are now saving the world at grad school and an electric vehicle startup. Two good eggs, for sure.

    In two weeks, I have six students starting the Herreshoff steam engine, another restoring the Universal Fisherman, and I'm looking for one or two to carry the Atlantic torch. Making the patterns for the cylinder, water jacket, cores, etc is quite involved. It'll happen though. In the meantime, I'm overhauling my Yanmar 3HMF. Too many engine projects that need to get wrapped up one at a time.... Maybe some students will make a trap skiff next year.

  13. #83
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I love that video. The putt-putt-putt of those engines is mesmerizing.

  14. #84
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I will be fascinated to read how you cast the head. I have one sitting on my porch right now and been wondering if I can do anything about the piston sleeve. I think the water jacket rusted so much that it deformed the piston sleeve. This past fall I was working at Fitzgerald's Shipyard in Chelsea and talked to the guys at machine shop next door about resleeving the head. They thought the cost would be prohibitive.
    Reading back through this thread I saw the questions about the drip oiler. I thought the oiler was used when these engines were first made until they realized oil could just be added to the gas directly. I figure they just never bothered to change the pattern. I always thought it was too bad they did away with the oilers since they look so neat.
    Knowing nothing about casting I was always in awe of how the Atlantic and many other engines were made without a removable head.
    One problem I had with my Atlantic 4hp is when I stopped running on dry cells I used my car battery. After about 55 hours of running the center post in my ignitor would pit. Not too much of a problem since you can just rotate the post. Then I went to 6 volt and after 55 minutes of running the post would be covered with black oil. I wouldn't take anything from my experience since I was losing compression through my shaft babbitts and my ignitor.

  15. #85
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Though it might seem a bit extreme, I might suggest it is possible to cut the waterjacket away, remove the rust from the inside of the waterjacket (which may in turn relieve the constricting force on the cylinder), then epoxy the pieces of the water jacket back in place.
    That may seem extreme, but if it is rust that is squeezing the cylinder onto the piston (which it very well can), then the water jacket is likely to plugged to function, so sleeving would be a waste of money anyway.

  16. #86
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Quote Originally Posted by DoctorB View Post
    I love that video. The putt-putt-putt of those engines is mesmerizing.
    I was at an antique engine meet...there were about a dozen engines running. The owners were in a zen state sitting listening to them run.

  17. #87
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I have taken an old hicks single cylinder engine out across Monterey bay a few times and the sound of that engine ticking over becomes the proverbial heartbeat. After maybe ten minutes you don't hear it at all. But let it skip one beat and it will wake you from a dead sleep!

  18. #88
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    One of the neat things you can do for these one lungers is put a load on them like the old factories had. They run much smoother. Loads were often just simple big props, sized to fit the engine being loaded.
    Ben Fuller
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  19. #89
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    How come the youngsters get to do all the neat stuff!?

  20. #90
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Hi Everyone. Happy Spring.
    Funny forum thing is I didn't get any notices of your replies. I'm glad this is still on your radar. We poured the manifold yesterday and had great success (sort of). The fill and surface finish was terrific, and using the high density foam patterns (and core molds) work realllllyyyy well. No finishing is required to release from the sand - right off our CNC onto a pattern board, powder, and voila! The issue was that the core print leaked and the core vent filled up with iron. So, the students will do it again, but our process is certainly improving.



  21. #91
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Very glad to see you back at it!!

    it looks really nice in the first,............ yeaaaaaa, ....... not so nice in the second

    You do have some pretty impressive equipment there, ....... that is the biggest bench vise I have ever seen! (in the second picture).

    it does amaze me how the engine builders of more than 100 years ago were able to do this stuff all day long, day in and day out with high success rates.
    Last edited by nedL; 03-04-2019 at 06:22 PM.

  22. #92
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    By way of background, here are some pictures of the core box and core. There are three internal features to the manifold - the gas intake (left), the central exhaust port, and an upper chamber (right) that is connected to the water jacket, though I don't really see cooling benefit without some mechanism to flow the water. The design calls for a 3/8 NPT plug on this water port, so maybe it was used as a water outlet at some time. At a minimum, the plug is used for a necessary core support. The sheet metal dividers were a "revision" - it made core removal easier. Just slide out the dividers, pop out the core, and glue the core together. Sure, the wall thickness is reduced by the sheet metal, so we'll use thinner shims next time.




  23. #93
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Okay, then....

    A new group of students, and an unfinished project. The Atlantic M&B has ramped up again, with seven students working to move this project closer (maybe) over the finish line. Updated CAD is largely done, incorporating many of the practices from the Herreshoff project. There is some remaining head scratching related to the cylinder water jacket, Peter Kinley and his team at the Lunenburg Foundry continue to assist and I'm sure things will get sorted out shortly.

    We started new patterns for the connecting rod last week and are planning on pouring this week. More later.







    The keen eye will notice these are duplicate halves, not mirror images. We are making two sets so we pour two at once hoping to increase our yield.

  24. #94
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    First pour this season. Went pretty well. We'll see after cleanup if it's a keepah.
    I'll let the pics tell the story.





    Everdur, though I'm not sold on this alloy for a connecting rod - it's a 4hp engine. I'll run some numbers for grins. We might pour again in C86300, though that's a bear to machine.





  25. #95
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    We’re really glad to see another group has picked this up and the project is continuing.
    The conn rod looks pretty good, will it be a keeper?

  26. #96
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Quote Originally Posted by DoctorB View Post

    I'm having trouble grokking the big-end cap. There's a boss on side where a bolt will go, but the other side looks like maybe it's being set up for a hinge of some sort?

    Pete
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  27. #97
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I think this engine does have a hinged conn rod cap. Some early engines did.

  28. #98
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Question for Ned...
    What is the approximate stroke of your water pump?
    (I have a similar engine that was missing the eccentric and I made another but suspect I over did it and it is a bit over-stroked, 7/8 inch I think)

  29. #99
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Yes, hinged and clamped at the crankshaft (and babbitted) with just a clamp up top. Interestingly, according to the drawings, there's no babbit or bushing at the piston pin.


    Canoeyawl, I know the question was for Ned, but for what it's worth, the water pump stroke on this J engine is 11/16" with a 1" diameter plunger.

  30. #100
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Thank you. Likely I overdid it!
    (The pump bore on mine is 1")

  31. #101
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Quote Originally Posted by DoctorB View Post
    Yes, hinged and clamped at the crankshaft (and babbitted) with just a clamp up top. Interestingly, according to the drawings, there's no babbit or bushing at the piston pin.
    I dunno, a bronze bush on the wrist pin was pretty common in small engines, and if the conrod is bronze to begin with, I don't see much value in adding a bush or babbit there. The relative velocities of those two parts must be pretty low too, especially in an engine like that - you guys are the mechanical engineers .
    I assume the bolt side of the big end get shimmed before the Babbitt is poured, so that shims can be removed as it wears, allowing it to be nipped up? It seems like a pointless complication otherwise.

    Pete
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  32. #102
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I suspect the wrist pin is firmly clamped by the connecting rod pinch bolt and only rotates in the piston.
    Pretty common, but the piston must be configured to lubricate at the wrist pin.

  33. #103
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    Original assembly drawings from 1918 had the wrist pin bushed, but piston and pin drawings from 1929 clearly indicate no bush. So, no bushing for us. The pin is hardened steel, while the piston is cast iron. I can only assume the gas/oil, rum, fishoil, whatever was used was adequate to lubricate that interface.
    There's an engine at the Fisheries Museum in Lunenburg that has been cross-sectioned. You are correct that there are shims at the crank clamp.

  34. #104
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    If you would like I can still measure the water pump throw on my Acadia.

  35. #105
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    Default Re: Atlantic Make and Break Fabrication Project @MIT

    I'm only curious, maybe the next time you are near it with a tape measure... Yes, thank you.

    The eccentric I made was just by guesswork based on the pump connecting rod i.d. and the o.a. length of the piston. I figured they wouldn't make it any larger than it needed to be, but after I completed the new eccentric it seems a little bit much at 7/8" stroke. Although it works, at the extreme end of the stroke there is a little less piston in the bore than out of it.
    My engine is an unknown brand, but it resembles an early Gray single, with a spark plug and stand up gear driven (reversible) timer (w/14" flywheel, 4"x4" bore stroke, it's probably 4-5 hp.)

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