Pseudoscope prototype parts

I just ordered the parts for the first prototype, I should be able to make at least two pseudoscopes out of the parts that I ordered, I doubled up on the one item I wasn't sure if I had enough parts for. Since I'll be lasercutting everything, each one can be a new version. Here's the McMaster order I just made:

  • One 8712K57 - ABS Rectangular Bar, 1/4" Thick, 3" Width, 2' Length
  • One 8712K34 - ABS Rectangular Bar, 3/8" Thick, 2" Width, 2' Length
  • One 94323A301 - Knurled Head Thumb Screw with Shoulder, Black Nylon, 6-32 Thread, 1/4" Length, packs of 100
  • One 91773A108 - 18-8 Stainless Steel Round Head Phillips Machine Screw, 4-40 Thread, 3/8" Length, packs of 100
  • One 90279A197 - Zinc Plated Steel Round Head Phillip Machine Screw, 8-32 Thread, 3/4" Length, packs of 100
  • One 1518T52 - Mirrored Extruded Acrylic Sheet, Adhesive Back, 1/8" Thick, 12" x 12"
  • One 90480A009 - Zinc-Plated Steel Machine Screw Hex Nut 8-32 Thread Size, 11/32" Width, 1/8" Height
  • One 90480A005 - Zinc-Plated Steel Machine Screw Hex Nut 4-40 Thread Size, 1/4" Width, 3/32" Height
  • Two 8586K162 - ABS Sheet, 1/8" Thick, 12" x 12", Black

So with shipping, it should still be well under $100, making at least two (possibly four or six) pseudoscopes. To make even more, I'll only have to order more mirrors and 1/8" thick ABS. Pretty much everything in this list was picked to be the cheapest possible. I'm not sure if I need the nylon thumb screws, they're to be a set screw to fix the large mirrors in place. I specifically picked nylon because I didn't want it scratching the ABS, but I'm not sure if I'll be able to get enough friction out of it. Hopefully it'll jam the mirror's pivot when screwed in without shifting the mirror too much to work. Another possibility would be to use any material thumb screw and a small rubber ball, but that'd be annoying to deal with and I'm aiming for simplicity in assembly for this design.

Once I get the design nailed down (hopefully with these parts or one more order), I'll learn how to use Ponoko and set it up there. I'll make sure a fresh set of parts from Ponoko works without any modifications, and I'll post the designs so people with a laser cutter can make their own. I'll also post assembly instructions, although the whole thing is really straightforward.

The main thing I'm not sure about for the design is how to hold it. My current plan is to pay attention to how I naturally attempt to hold the prototype and adjust the design so that way is easier. I suppose I should also grab someone left handed and have them to the same thing. I can probably use some scrap pieces to design a handle instead of having to buy more materials to figure out what it should be like.

I think a single pseudoscope of the current design uses about $18 of materials, including scrap. That's excluding laser cutter runtime cost, the cost of extra nuts & bolts that aren't used, shipping and tax. If my estimations are right (they're a little pessimistic about material used, but the measurements are from memory), I barely need to make this any cheaper. The main expensive part (the reason that this first order is near $100) is the fact that I didn't pick my parts well. I have to order a lot of extras because there isn't a good way for me to buy just the right amount of everything.