Building Rudy's Steam Tractor

Discussion in 'A Work In Progress' started by 4156df, Mar 6, 2009.

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  1. Mar 6, 2009 #1

    4156df

    4156df

    4156df

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    I’ve started a build of Rudy Kouhoupt’s Model Steam Tractor. The tractor is 3/4” scale and is loosely based on the J.I. Case steam engines. To quote Rudy, “…it is not an exact scale replica. Some of the parts have been arranged to improve the ease of construction of the model or to insure its dependable operation.” The part about “ease of construction” was strangely appealing.

    I purchased a set of plans that have been recently published by Village Press. This will be the first engine I intend to operate with steam, so having plans to work from should be a good thing. My plan is to build the rear wheels first (they look like the hardest part to me) and if that goes well then proceed with the rest of the engine.

    Interestingly, Rudy’s original engine, which he built for his Popular Mechanics article (Feb. 1971), is at the Craftsmanship Museum in Vista, CA. The museum is about 40 miles from me. I expect to make several trips there as this build goes along. Here’s a photo I took of it.

    [​IMG]

    The rear wheels are supposed to be brass, 4 1/2” OD & 4 1/4” ID, fabricated from a cast-brass pipe adapter. Good luck finding one. The closest I could come in brass was a threaded specialty connector for $148 and I would need two!! I’m barely started and I have to deviate from the plans. However, I guess being able to do that is part of the beauty of model engineering and of not building an exact replica. Anyway, I ended up selecting a 4” copper sweat fitting that is 4.350 OD and 4.136 ID. Close enough. Thirty-eight bucks, but I get two wheels from one fitting. The other raw materials are 1” brass rod for the hub and 3/32” rod for the spokes.

    [​IMG]

    For the rims, I cut two 1 1/2" wide rings from the coupling.

    [​IMG]

    Since I’ve only got a 6” lathe, I had to get creative to face the edges (Rudy says this can be done with a file!?).

    [​IMG]

    Next step…spoke holes. There are 24 spokes per wheel, twelve to a side, staggered so the two sides are off-set. To drill the holes I layed out the spoke pattern and glued it to a wood fixture (I’m a big fan of wood for one-time fixtures). The way this one works is the black lines represent one side’s spokes and the red the other. Line up the reference line on the inside of the rim with either a red or black line, drill, move the reference to the next line of the same color and so on. Then reverse the rim and drill the other side using the opposite color lines. I first spot drilled and then thru drilled.

    [​IMG]

    Drilling the copper didn’t go so well until I got some info from helpful people on this board (see thread on “Drilling Copper). The trick is slower speed (1000 rpm or slower) and coolant (preferably tallow).

    Each wheel has 24 “grouters” fastened with rivets. They’re fastened such that two of them fall between each spoke. Rudy’s suggestion was to drill the holes on one side of the rim and then use the grouter as a guide to line drill the other side during assembly.

    The rivets will be 1/16”, but I used a #51 drill which makes it just a little easier to get the rivets in. I used the same drill fixture as for the spoke holes, but used a new reference line set off the proper distance from the original reference. Then I aligned the new mark with each of the spoke lines, spot drilled and then thru drilled.

    [​IMG]

    After the holes were all drilled, I deburred the inside using a 3” diameter scotchbrite wheel in the drill press.

    [​IMG]

    Next thing to tackle are the hubs. So far so good.

    Regards,
    Dennis

    P.S. I tried smaller photos for this post. Are these the right size or should I go back to larger ones??


     
    cardinalis1 likes this.
  2. Mar 6, 2009 #2

    rleete

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    Nice, informative post. I like the simple setups.

    Pics are just fine.
     
  3. Mar 6, 2009 #3

    steamer

    steamer

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    Cool...always wanted to watch that build.

    YES the pics are good! :)

    Keep them coming......

    Dave
     
  4. Mar 6, 2009 #4

    Maryak

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    Looking good. :bow: Now I know why the question on drilling copper. ;)

    Best Regards
    Bob
     
  5. Mar 9, 2009 #5

    4156df

    4156df

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    The hubs are a basic turning operation. They’re drilled 0.250” and there’s a 6-32 set screw in the center of the hub for securing the wheel to the axle.

    [​IMG]

    The spoke holes are drilled to match the holes in the rims with 12 spokes per side staggered so the two sides are offset. I used a locating method similar to the one used for drilling the rims. The fixture is positioned on the drill press for the first side. Twelve holes are drilled using the black lines for reference, then the fixture is re-positioned for the second side and the holes are drilled using the red lines for reference. Holes were spotted with a spotting drill and then drilled. The hub is 1.5” long and 1” diameter. Spoke holes are 3/32”.

    [​IMG]

    Wheel assembly tomorrow.

    Dennis
     
  6. Mar 9, 2009 #6

    ksouers

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    Dennis,
    Following along.
    Very creative indexing solution. :bow:


    Kevin
     
  7. Mar 9, 2009 #7

    cfellows

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    Nice looking build, Dennis! I'll be watching the progress.

    Chuck
     
  8. Mar 9, 2009 #8

    DougLanum

    DougLanum

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    http://Dennis,
    Nice Job.
    This tractor was my first project about 30 years ago.
    Mine has a lot of miles on it. I'd take it to an engine show and the kids or "Crawling engineers" come out of the woodwork to steer.
    I made my wheels from steel tube, the cross head design was made closer to what Case manufactured, and the gearing was reduced so the tractor moved at a more realistic speed.
    Please keep sending updates and if I can answer any questions don't hesitate to ask.
    I'll try to attach a photo.
    Doug

    [img]


    IMG_0178.JPG

    IMG_0177.JPG
     
  9. Mar 9, 2009 #9

    DougLanum

    DougLanum

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    My Message got lost, but the photos got sent ??

    Nice job Dennis, please keep us updated. I built one of the tractors as my first project about 30 years ago. It has many miles on it.
    I take it to an engine show and the kids "crawling engineers" come out of the woodwork to steer it.
    I used steel pipe for my wheels, changed the cross head design to match the Case design more and reduced the gear ratio so the tractor moved at a more realistic speed.
    Don't hesitate to ask question if you need help

    Doug
     
  10. Mar 9, 2009 #10

    4156df

    4156df

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    Doug,

    Nice job on your engine. I've been hoping a few builders would pop up as I go along. I know I'm going to have questions, particlarly as I get closer to running it. The plans have absolutely no info on them about operation.

    Regards,
    Dennis
     
  11. Mar 10, 2009 #11

    ghart3

    ghart3

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    Dennis, built one also from the magazine plans. I agree with Doug on more gearing down needed. Like Doug's crosshead and suggest you think about doing the same. I followed the plans and there is lots of flexing. I made the start of an extra heat exchanger with raised CASE letters. You or anyone else building one of these is welcome to it

    Looks like you got good start

    Gary
     
  12. Mar 10, 2009 #12

    4156df

    4156df

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    Gary,

    Thanks for the input. I liked the look of Doug's crosshead too...hadn't considered the operational benefit. I haven't ordered the gears yet (I'm not ready to make my own!) so I'm going to re-think them before I do. Any clues as to ratios will be appreciated. I've got some time before I need them. Also like the idea of a more to scale heat exchanger.

    Regards,
    Dennis

     
  13. Mar 10, 2009 #13

    ghart3

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    Dennis, didn't keep notes on the gears. Eye balling it, it looks like added an 80 and 40 tooth gears for another 2 to 1 reduction. Think even more reduction would be ok, but that would depend on how you want to use it. I'm old and slow so like slow.

    You can have the start of heat exchanger and still have a Teflon pattern for making raised letters that someone else can have if they want.

    If you have a way to print out dxf files let me know. Got drawings that I made of the sheet metal. What I did was print them out and used Elmer's wood glue and put on the sheetmetal. Which was from junked out freezer. Drilled all the holes, cut out and broke (bent up). Rudy's drawings were so good that all most everything lined up.
     
  14. Mar 10, 2009 #14

    4156df

    4156df

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    Wheel Assembly

    The 48 spokes are 3/32” rod cut to 2” and de-burred. They’re ground to final length after assembly.

    I have a small hot plate that I plan to use as an auxiliary heat source during soldering, so I made a combination assembly/soldering fixture out of a 6” x 6” piece of steel. It should be usable for the front wheels too. The wheels are soft soldered.

    [​IMG]

    I slid the spokes into place and then added a soft solder pre-form at each connection. The pre-forms were made by winding 0.032” solder around a 3/32” drill bit.

    [​IMG]

    [​IMG]

    After the pre-forms were applied, I brushed a drop of rosin flux on each joint and pre-heated the assembly on a small hot plate (don’t think the hot plate was necessary). I used a simple Bernz-o-matic propane torch for final heat. The rosin flux washes off with alcohol.

    [​IMG]

    The pre-forms really help with solder control.

    [​IMG]

    After cleaning, I clipped the protruding part of the spoke, filed it flush and buffed the outer rim with 3M maroon abrasive.

    Next, the grouters.

    Regards,
    Dennis


     
  15. Mar 10, 2009 #15

    joeby

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    Lookin' good!

    I will be following this along, as I have one of Rudy's books stashed away in the future projects file.

    Kevin
     
  16. Mar 10, 2009 #16

    joe d

    joe d

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    Dennis

    I really like how this is going so far. Since I'm another with this project on the 'round-to-it list, keep on posting, please!

    Cheers, Joe
     
  17. Mar 11, 2009 #17

    cfellows

    cfellows

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    Nice job on that wheel assembly! :bow:

    Chuck
     
  18. Mar 11, 2009 #18

    shred

    shred

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    Nice.. this one is on my to-do list soon.
     
  19. Mar 12, 2009 #19

    Maryak

    Maryak

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    4156df,

    Big Wheels keep on Turning - fantastic job :bow: :bow:

    Best Regards
    Bob
     
  20. Mar 13, 2009 #20

    4156df

    4156df

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    Grouters

    There are 48 “Grouters” (24 per wheel) set at a 67.5 degrees from the wheel edge. They’re fabricated from 1/32” brass (Rudy calls for steel) and fastened with two 1/16” rivets.

    As an aside, does anyone know why they’re called grouters? I grew up in the Midwest (Minnesota) and we always called them lugs. Also, is there anything magic about 67.5 degrees?

    I was lucky enough to borrow a small 12” shear for this project (not really necessary, but a real help). I laid out the grouters on paper, taped the pattern to the shear and mounted a guide bar as shown. Then it was a simple matter of feeding in a 1 1/2" strip of brass, cutting, and advancing to the next line. If I didn’t have the shear, I would have rubber cemented the layout to the brass strip and cut them by hand.

    [​IMG]

    And here they are, less holes.

    [​IMG]

    To drill the holes, I made a fixture by milling a 1/4” x 1/16” deep slot in a piece of aluminum and super-gluing a strip of brass to the end to serve as a stop. A 1/2" hole serves as a press point to pop the part up and out of the fixture. The fixture is clamped into position and you drill away. I spot drilled first, then through drilled with a #51 drill. Since I was planning on flush rivets, I ran them through one more time and put a small countersink on each hole (this also de-burred the exit hole).

    [​IMG]

    Ready to install:

    [​IMG]

    Regards,
    Dennis

     

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