HO Bachmann Spectrum 44 ton to HOe/HOn3 Oahu Railway GE 47 ton

Discussion in 'Narrow Gauge Model Railroading' started by Canopus, Mar 22, 2006.

  1. lv4142003

    lv4142003 Member

    Joined:
    Jun 2, 2005
    Messages:
    42
    Likes Received:
    0
    Did you replace the wheels with larger ones? lv4142003
  2. bertschi

    bertschi New Member

    Joined:
    Jul 5, 2006
    Messages:
    4
    Likes Received:
    0
    47-tonner wheels

    I left the original N-scale SD-9 wheels on, since the original plastic center gears on the SD-9 were too small to drill out to fit the axles Bachmann 44 tonner HO wheelsets. The SD-9 axles were really tiny, about 1 mm in diameter. Also there were clearence problems with HO wheels -I would have had to grind awa the plastic center tab that held the SD-9 axles/gears and sideframes to the trucks (sandwich-style). A benefit (if you can stand the non-scale wheel diameter) is that the loco runs slower (closer to prototypical speeds) since the same number of RPMs on the axle causes the smaller wheel rim (*think circumference) to roll a shorter distance than with HO wheels-essentially another "reduction gear".
  3. Canopus

    Canopus Member

    Joined:
    Mar 16, 2006
    Messages:
    216
    Likes Received:
    0
    I believe he said that he did not, since it was not noticeable.

    I'm inclined to disagree that it isn't noticeable, but would rather say it doesn't make a huge impact on the appearance of the model. Since the model is mostly accurate, and since the wheels only make up a very small part of the overall model, I'd say it's not an issue unless you absolutely insist on prototypical details.

    What I do question is his statement that the gears were 1mm in diameter! I'd accept maybe 3mm in diameter, I think that's reasonable. But a 1mm diameter gear would require an axle of approximately 0.5mm or smaller.

    It is possible to purchase and fit replacement wheels of a larger diameter, but I'd only be repeating what's already been said by saying that sometimes it isn't practical.

    Of course, scratchbuilding a chassis eliminates any element of compromise, but that takes a lot more skill, effort, and time (considering you have to track down and purchase all the corresponding parts).
  4. bertschi

    bertschi New Member

    Joined:
    Jul 5, 2006
    Messages:
    4
    Likes Received:
    0
    Dear Canopus,
    The N scale AXLES were about 1 mm in diameter, and the plastic bearing hubs projecting from the gears were about 3 mm in diameter, which was not much bigger than the Bachmann 44-tonner axles. (The gears were probably more like 4-5 mm in diameter). A look at the underside of a life-like N scale SD-9 shows this clearly.
  5. Canopus

    Canopus Member

    Joined:
    Mar 16, 2006
    Messages:
    216
    Likes Received:
    0
    My apologies, I must've misread.

    Out of interest, was this conversion undertaken on the old bachmann 44 tonner, or the newer retooled version?
  6. bertschi

    bertschi New Member

    Joined:
    Jul 5, 2006
    Messages:
    4
    Likes Received:
    0
    47 ton dropcab

    Dear Canopus,
    I used the old Bachmann 44-tonner (I did the two 47-ton dropcab conversions in 1999-2000).
  7. lv4142003

    lv4142003 Member

    Joined:
    Jun 2, 2005
    Messages:
    42
    Likes Received:
    0
    Canopus, did you finish the 47 tonners ? I haven't been here for a while and wondered if I missed the finish. lv4142003
  8. Canopus

    Canopus Member

    Joined:
    Mar 16, 2006
    Messages:
    216
    Likes Received:
    0
    No I didn't, and every time someone brings this thread back or mentions the project it reminds me that I REALLY need to get on with it!

    Since I last posted, I've built my own self contained motor unit, which uses a mashima motor to give power to a single axle. I need to get around to finishing the trucks, because I've also managed to lose one of the truck frames, so I'll have to fabricate one. I still need to build the chassis, and find some wire to do the handrails. But once I've done that the model will be complete.

    I'm currently at the start of a week's holiday, so I should have plenty of time to do some modelling!
  9. Maxxi

    Maxxi New Member

    Joined:
    Feb 24, 2012
    Messages:
    1
    Likes Received:
    0
    Hello ,
    where can I find the drawing ? Have some thoughts to build the 47ton in Sn3.
    Roland
  10. Bill Nelson

    Bill Nelson Well-Known Member

    Joined:
    Dec 15, 2008
    Messages:
    2,448
    Likes Received:
    148
    How did I miss this

    Good work, glad to see some work in this area. I like the looks of this animal. I have been giving some consideration as to weather the same conversion I used on the bachman GE 70 tonner (over in the Hon3 engine shops thread) would work with one of the center cab Ho GE units


    thanks for sharing.