Building the Peake 2, Castings and All.

Discussion in 'A Work In Progress' started by BenPeake, Nov 7, 2010.

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  1. Nov 7, 2010 #1

    BenPeake

    BenPeake

    BenPeake

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    Hi everyone,

    Here is the build thread for the Peake 2, my next engine. I will be making 25 of these and they will be single acting "upside down" steam engines. The first parts I need to tackle are the patterns for the castings. I decided to begin with the flywheel because it is the most fun! The flywheel is 3.5 inches or 89mm in diameter once finished. The hub and curved spokes are cast from alluminium and the rim is mild steel (to add weight and improve appearance). Here are the pics.

    Preparing greensand from raw sand:

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    Drying the sand.

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    Sifting the sand to remove unwanted larger particles.

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    Adding bentonite clay and water until correct consistency is reached. The clay must not be too wet (could cause an explosion when poured into) and must be well mixed. A good test is compress a handful of sand in the palm of your hand, hold it with a thumb and finger at each end and 'snap' it in half. The break will be clean and no sand will fall away if everything is right.

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    As I don't have a CNC mill, I have to make my patterns the old fashioned way. I have cut the hub and rim into a block of wood, which will act as a 'stamp' in the greensand.

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    The spoke stamp is formed from a piece of brass. In this picture it has been tapered by between 1 and 2 degrees.

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    As the spokes are curved, the spoke stamp must be curved also.

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    The spoke stamp is parted and ready to go. I had to re-make both these stamps with slightly larger dimensions for reasons which will become apparent, which is why some of the following pictures will show modified versions of them.

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    The spacing for the spoke impressions in the sand is controlled by this piece of paper.

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    I mounted a pencil in the toolholder so I could accurately draw on the paper.

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    The paper is marked out with the OD and 5 marks for the end of the spokes.

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    I used a drill bit to index the spindle, a trick I picked up from someone on this forum.

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    Finished paper.

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    Making the hub and rim impression in the sand. (this picture is of the impression made with the third version of this stamp)

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    Indexing paper is in place. Spoke impressions are now made corresponding to the marks on the indexing paper.

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    Impression is finished

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    Forming the Cope

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    The cope and drag are in position, ready to be poured.

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    Scrap alluminuim is heating up in the furnace (shown without lid).

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    The firt pour!

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    Failed! This is why I increased the dimensions of the stamps.

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    Skipping forward to the fourth Pour.

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    And the sand reveals a welcome shape.

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    So here is half of the pattern, prior to machining and tidying up. I had to call it a night at this point - getting late!

    In the morning I will be making the other half of the pattern.
     
  2. Nov 8, 2010 #2

    Lakc

    Lakc

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    We need a smiley grabbing some popcorn, because I love a good casting thread, and this one looks to be no exception. :bow:
     
  3. Nov 8, 2010 #3

    nfk

    nfk

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    Nice work!
    Castings are in my to-do list, maybe in a couple of years ;)
     
  4. Nov 8, 2010 #4

    max corrigan

    max corrigan

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    Ben that's brilliant and a very easy to understand build up! great :bow: :bow:
    Regards Max..........
     
  5. Nov 9, 2010 #5

    BenPeake

    BenPeake

    BenPeake

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    Glad you're all enjoying this! I know I'm having a blast.

    [​IMG]

    Setup for machining

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    Post machining.

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    The rim and hub impression is made for the other half of the pattern.

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    Using the first half to "trace" a guide for the spoke impressions using talc.

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    Finished impression.

    I won't go through the casting process again as it is exactly the same as the first half. So I'll skip to when the second half of the pattern has been machined.

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    Drilling the central locating hole. I then lined the two halves up and drilled right through, but forgot to take a photo.

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    The two halves are fastened together making sure they are in the correct orientation.

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    The second locating hole is drilled in the outer rim.

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    A locating pin is inserted.

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    Filing begins. The aim is to make sure the two halves meet exactly at the seam.

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    I used strips of sandpaper to remove irregularities in the surface.

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    The outer rim is machined making sure to include a taper either side of the seam so the pattern can be easily removed from the sand.

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    There were a couple of places where the alluminium didn't flow for whatever reason. No big deal. I filled them up with an epoxy.

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    Gluing in the locating pins and covers with Loctite.

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    Added a couple of tapped holes so I can easily grip the pattern to remove it from the sand.

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    Woo Hoo! Pattern is finished. Very happy with the result. I think this will make for many very eye-catching flywheels.

    Thanks for checking this out.
     
  6. Nov 9, 2010 #6

    swilliams

    swilliams

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    Very nice job you are doing here Ben. Will you be using other materials in any of the castings for this build, or are they all going to be aluminium?
     
  7. Nov 9, 2010 #7

    BenPeake

    BenPeake

    BenPeake

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    Thanks! All the castings will be alluminium for this build. In future builds I will be attempting to cast brass and one day I hope to be able to cast iron.

    Cheers,
    Ben
     
  8. Nov 9, 2010 #8

    coopertje

    coopertje

    coopertje

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    Hi Ben,

    Complements on your casting, they look perfect! I am not sure if I would have the patience without using a CNC mill, so nice to see how you build the mold by hand :bow:

    Looking forward to follow along with your build!

    Best regards Jeroen
     

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