Preferred method (technology?) for making really small holes?

Mark St Clair Oct 17, 2020

  1. Mark St Clair

    Mark St Clair TrainBoard Member

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    I would like your inputs on how to overcome a challenge. Please have a read and let me know how you would approach this problem.

    My need to build some ladders for an N scale tender has become an opportunity to attempt some accelerated learning on modern model building. Here is a drawing, admittedly not machine shop ready, illustrating what I am after. Material is brass.
    Screenshot (9).png

    The next challenge is drilling holes in the rails for the steps. I can actually do a fair job of drilling the holes by hand. Accuracy is quite a different challenge with my current skill set.

    Several idea have been rolling around my head. Here is a summary of thoughts and questions:

    1. My old drill press and cross vise are not going to get me there. Is there a jewelers drill press and x-y table combo that offer the accuracy needed? Which ones: Proxxon, MicroLux, Cameron ($$$$), etc.

    2. Could a 30/40W laser cutter dimple the brass sufficiently to substitute for a center punch?

    3. I wanted to scratch build with brass. Would you use a different approach? Say scratch build with styrene, 3D print, photo etch, etc.?

    My skill set is still stuck at about 1999. I am beginning to see the possibilities of CAD, CNC, laser cutting and 3D printing. Maybe you can help me up a steeper learning curve by sharing your insights and experience.

    Thanks!
     
  2. rray

    rray Staff Member

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    I used a 30W laser to drill these .009" holes in white Polybak (plastic and cellulose mix) for my brakeman platform:
    Image1.jpg

    To use a laser with Brass, you need a 50W Fiber Laser, and several passes, but it could go through. I use a 30W CO2 laser and a combination of Paper, Wood, Polybak, and Plastic, with brass details to build my models.

    I drew up your ladders in Corel in 5 minutes. I would cut them out of .011" black Polybak and they would be 3 layers thick, with the rung layer in the center:
    Capture.JPG
     
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  3. r_i_straw

    r_i_straw Mostly N Scale Staff Member

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    I use a Dremel setup.
    IMG_0171.jpg
     
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  4. Mark St Clair

    Mark St Clair TrainBoard Member

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    That's great info. Never would have come up with that approach on my own. How narrow can the rails and rungs be cut?
     
  5. Mark St Clair

    Mark St Clair TrainBoard Member

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    Now that technology is familiar enough. I am curious how you clamp the brass (.010" x .030") strip and drill the holes on the centers (.070", .074", .072")?
     
  6. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

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    3D printing can do dimples for drilling, but the resin material may be brittle when drilling. Tough resins exist, but adds cost (~50-75% more $), and might be an alternative.

    If accurate repeatability is key, why not make a drilling jig out of brass? An example is Gold Medal Models 160-56 http://www.goldmm.com/nscale/gmnlotyp.htm.
     
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  7. wvgca

    wvgca TrainBoard Member

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    a drilling jig would give repeatability and accuracy ... a simple dremel as pictured above would be a relatively low cost way to drill the resulting holes
     
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  8. r_i_straw

    r_i_straw Mostly N Scale Staff Member

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    I use the Gold Medal Models jig and a piece of double stick cellophane tape to position the holes. I also can make dimples with an X-acto awl.
     
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  9. rray

    rray Staff Member

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    .009"
     
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  10. mah2219

    mah2219 New Member

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    Hi guys. I'm working on a laser cut project of a local depot. I'm cutting the walls out of 1.5mm ply but hoping to 'skin' this with engraved brick. I've been working with .024 wood veneer and have been able to source .020 polybak. The .011 white polybak sounds like it would be ideal. Do you have a source you can share for this material?

    Thanks,

    Mike
     
  11. rray

    rray Staff Member

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    The .011" polybak used to come only in Black, but I think it is brown now. The .015" polybak used to be white, and came from either Midwest Products or Northeastern Scale Lumber and they called it Laserboard. I have never used the .020" brown, but I do use the .024" brown polybak.

    I bought Karin Snyder's last 20 sheets of white .015" polybak just before she moved away to Alaska earlier this year, and was told the white has been discontinued. I use it exclusively for Z Scale railcars because it is exceptionally smooth and hard, and can represent steel carsides best.

    You can get polybak here, but they call it Laserboard, and I think it is all brown these days:
    http://automatedartists.com/laserboard
     
  12. Mark St Clair

    Mark St Clair TrainBoard Member

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    Update on my quest to make some really small holes:
    WIN_20210214_20_42_01_Pro.jpg
    The holes are nominally .010" in .030" wide strip. Spacing is .070" between centers. The top strip was made with a 00000 center drill, but I had trouble controlling it. The next two were made with an end mill. That is a #80 (.0135") bit for comparison. I am quite pleased with the results so far. A few more to make before moving on.

    Tony Burzio from the Nn3 group deserves the credit for setting me down the path. He observed, "What I think you want is a mill." Turns out I had the makings of one with only nominal additional expenses for materials and cutting tools.

    The quest was very educational for me. For example, Robert Ray's suggestion has prompted me to begin learning CorelDRAW. Laser cutting sometime in the future. I also got a Dremel stand for Christmas. It has already proven it's worth for several projects including the setup required for the strips.

    So thanks to everyone for your input. The possibilities for my modeling expanded quite a bit in this exercise. Way beyond making some really small holes.

    Stay safe,
     
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