Cast Iron Wheels for Pouring Trolley

Discussion in 'Foundry tools and flasks' started by Melterskelter, Sep 9, 2022.

  1. Melterskelter

    Melterskelter Gold Banner Member

    A few years ago I made a pouring trolley. I have used it many times with excellent results and have yet to have a tire burst during a pour due to iron droplets falling in the vicinity of the tires. But, I have come close a few times. Another risk to pneumatics in the foundry are the little droplets of cold iron that sometimes have very sharp "tails" on them. So, in the interest of reducing pour failure opportunities, I am planning to pour iron replacement wheels for the existing "8 inch" pneumatics which are actually 10" OD. You can see the trolley in use at this short video:



    I've been using Onshape to draw various patterns over the last couple months. Here is what I have come up with to date. It is something of an homage to old timey pulleys that were often designed with curved spokes. I am not entirely sure why that was done and would be interested in any insights members might have on that question.

    Trolley Wheel.jpg

    If anyone cares to look at the actual drawing, I titled the file
    "Trolley WheelsDGF123" By logging into Onshape (free registration with no app to download, BTW) and searching on that title, you should be able to view the actual drawing and manipulate it and potentially copy it, if desired.

    I am currently tossing around gating options which I think will be done on the periphery gating into the flat "tire" at the locations of a couple spokes and then incling the mold gate side down. I am interested in any thoughts people might have on improving the design or gating.

    Ultimately the casting will be bored to accept a 5/8" axle. I will likely leave the OD as cast if it is not too ugly.

    Onshape does calculate the weight of the casting too. It should be "5.298" pounds. ;-) It will be interesting to see how close the estimate comes. I will guess it will be within a percent or two.

    Denis
     
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  2. Mantrid

    Mantrid Silver

    Not sure but my theory would be as a kind of suspension. Because of the curve they would bend slightly under force where as the straight spoke would not as it would have to compress to achieve the same result, and metal doesnt compress as well as it bends
     
  3. Melterskelter

    Melterskelter Gold Banner Member

    Kinda my suspicion as well. Also might diminish chances of hot tears.
    Thx.
    Denis
     
  4. Smoking Shoe

    Smoking Shoe Silver

    If you really want to cast them I understand. We do a lot of this just for fun. But..............
    A couple of cheap solid tire wheels from Harbor Freight solves the pneumatic problem.
     
  5. Tops

    Tops Silver Banner Member

    Denis, are you going to 3d print the pattern or develop it from other materials?

    PS I am thinking more of a 'flamey' motiff...:D

    image001(3).png
     
    Last edited: Sep 9, 2022
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  6. Melterskelter

    Melterskelter Gold Banner Member

    I’d like to think pretty much everything I’m doing in the foundry is “for fun.” So, sure, the cheap wheels would do the job. And I have pinch rolls and could weld up wheels easily enough. But, iron tires reminiscent of classic castings are more interesting. These need some tweaking. But having printed 1/2 the wheel lets me get a better idea what will be needed.

    Love the flames!. Maybe I could paint on bright orange flames like those seen on 56 Chevy hoods with blowers poking out would be good!

    Good for you for finding the drawing and having some fun. Are you an Onshape “veteran?”

    Denis
     
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  7. Tops

    Tops Silver Banner Member

    Thanks, just goofing off for now. I am not a veteran Onshape user. The hobby signup process was easy and the basic steps like sketch, extrude, pattern were quite easy to use.
     
  8. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Less distortion and greater dimensional accuracy for the ring portion as the casting freezes.

    Best,
    Kelly
     
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  9. Melterskelter

    Melterskelter Gold Banner Member

    685C1AE2-0C7C-4E79-926E-93B25D5E0750.jpeg C621DC14-B8DB-4928-BF1E-20F5FF269C4E.jpeg I've been playing with Onshape and got a boost from a mentor on some drawing methods to make shapes more organic and to allow easier handling of text. I am starting to like this rendition pretty well. Sorry that the image copying methods I used result in somewhat poor rendition.

    OD is 8”

    Denis



    [​IMG]

    [​IMG]
     
    Last edited: Sep 12, 2022
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  10. Tops

    Tops Silver Banner Member

    My two-wheeled dolly was flat in both tires last weekend. If only I had me a set of Foster's Featherweights...cast iron run flats for shops of distinction.
    And then a set of 14-inchers for a bandsaw...
    How's it coming Denis?
    :)
     
  11. Melterskelter

    Melterskelter Gold Banner Member

    I beefed up the drawing I recently posted a bit and am printing 1/4th of the pattern right now. Every vertical surface has 3 deg of draft. (Interestingly, Onshape has a built in command to examine drawings to detect inadequate draft and undercuts.) I had to split it (done in the CAD program) radially as I want a split pattern for molding and I split it again vertically so that it would fit onto my 3-D printer platen. The first portion will be finished in an hour and a half. Each of the four pieces will take about 8 hours on a fairly high resolution printing setup. But, I will say that making such a pattern in my woodshop would have been very difficult and would have taken a week of careful work. I doubt I could have made it as accurately or as fairly. And in the program to scale it a bit from 8 to 10 inches, say, takes only a couple clicks and it's done. The filament cost is less than 10 dollars for the whole works. Final finishing the print should be quite brief and simple if prior experience with my printed patterns is any indication.

    10 inch Wheel Beefed Up.JPG

    10 inch Wheel Beefed Up2.JPG
    Here is the hub detail showing the location of the cut just missing the "T" and "H."
    10 inch Wheel Hub Detail.JPG
    I do think such a wheel could easily be adapted to a bandsaw application. ;-)

    Denis
     
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  12. Ironsides

    Ironsides Silver

    When I first built my pouring trolley 25 years ago I thought the same thing and used solid lawnmower wheels. I then wanted to film the pour with my camera mounted on the trolley but solid wheels made the camera vibrate too much so I used pump up wheels from a pram. This solved the vibration problem but it was always in the back of my mind what happens if I run over an iron spill? Have a look at my video at 3;00, those pram wheels are more resistant to punctures than I thought.

     
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  13. Melterskelter

    Melterskelter Gold Banner Member

    I just finished printing the 4 segments of the 10" wheel in PLA. I glued the two top halves together and the two bottoms. I'll be using them as simple split casting as I figure I'll only make a couple wheels.

    They printed quite well but not perfectly. Due to internal stress the two halves with thin unbalanced spoke segments tended to warp a bit. They were perfectly flat on the platen. But when released there was some evident warpage. Nothing serious, but I will need to add a bit of Bondo to the joint line on one side. And there will be a bit of hand sanding of the surface and then a few coats of lacquer. But, I expect the time spent finishing these patterns to be trivial compared to making them from wood. The printed parts are pretty strong and will not be damaged by simple handling or minor traumas as the plastic is pretty tough. I used medium thickness cyano glue to join the pieces. PLA seems to take gluing very well with cyano or epoxy glues.

    Wheel2.jpg Wheel1.jpg Wheel3.jpg Wheel4.jpg

    I hope to cast a couple wheels in the next few days.

    Denis
     
  14. Melterskelter

    Melterskelter Gold Banner Member

    Hot em with two coats high-build primer. 8B0EC8AC-446E-4056-BD5F-F5CB8AE6EAE5.jpeg 6C963E81-3BF9-4372-9070-3CB5337D8638.jpeg
    Now I’ll let them cure for a couple hours and do some sanding.

    Denis
     
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  15. Melterskelter

    Melterskelter Gold Banner Member

    And after hand sanding each primed piece about 20 mins with 120 paper, I applied 2 coats of Rustoleum Lacquer. I think ready to mold!
    The 4:1 high-build primer that DavidF told me about is amazing stuff and took this from fairly rough to ready to sand in 2 coats separated by 10 mins and the pair allowed to dry 70 mins (2 hours is what the can says)after priming.

    2 Coats primer and 2 coats lacquer.JPG

    I'll drill a couple pin holes through the pair to make it possible to reliably line them up when molding.

    Denis
     
  16. Tops

    Tops Silver Banner Member

    Nice fill and sand!

    I put the hair over 1/8" pinning holes .128" [3.28mm) into the 3d model/print and then use bits of 1/8" [3.2mm] dowel for pins, 'superglued' (isocyanate) into the cope side. That way the slicing software builds a wall around the holes. Drilling into an unplanned part of a lightly-infilled model only gives you support skin deep.
     
  17. Melterskelter

    Melterskelter Gold Banner Member

    You are right. I should have included infilled spots for the pins. But, I have drilled over-sized holes, filled with Bondo and then drilled pin holes. Works fine. But better to do the reinforced areas.

    Denis
     
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  18. crazybillybob

    crazybillybob Silver Banner Member

    Any info yo can share on the 4:1 high build primer? (always looking for quick ways to smooth prints!)
     
  19. Melterskelter

    Melterskelter Gold Banner Member

  20. Melterskelter

    Melterskelter Gold Banner Member

    BTW,

    I rammed up two molds using the new pattern this morning. It drew nice and cleanly. That is a reliuef to know the pattern is OK.

    Sand.JPG Sand2.JPG

    Denis
     
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