Instructables

Portable Drafting Kit from Form Holder

Picture of Portable Drafting Kit from Form Holder
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Take a form-holder, add a custom t-square and rules along edges -> portable drafting tool with storage for drawings, pens, etc.

Project is pretty simple, though time consuming; total construction time was around 4-5 hours. Most of this is making all the rule marks, so if you sacrifice function a bit, you could get construction down to around 2-3 hours.
For materials, you'll need a bit of acrylic or polycarbonate (plexiglass or Lexan), a form holder (try Staples, about 17$), epoxy, crayon, and paper.
For tools, you'll need clamps, a file, a box-cutter, a saw (like a band saw) for cutting the plastic, sandpaper, and a square.
 
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Step 1: Fabricate the T-Square

Picture of Fabricate the T-Square
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GluingRuler.JPG
Cut the plastic into the shapes shown below. Some notes:
  • The 3.5" dimension is arbitrary. I feel that it is sufficient, but if you'd like, you can make it longer, to make the T-square more stable.
  • The 7/8" width of the small piece is also arbitrary, but works well. It is wide enough to prevent it from wondering too much during glue-up and narrow enough to not be huge.
  • Leave a bit of margin for error on each side of the straight-edge part of the T-square. This is because you will be truing it up so that it is perfectly straight and of uniform width, and you'll need some material to work with.
Once that's done, true up one edge of the straight-edge on the T-square so that it is straight. I tried a couple of techniques to do this, but the only one which I could get to work was optically:
  1. With your eye, look along the length of the edge.
  2. Mark the high spot(s) with a marker.
  3. Clamp the piece to the table and file off some of the high spot(s). Make sure you keep the file square with the T-square.
  4. Repeat steps 1-3 until you can't determine where the high-spots are.
File the other edge of the straightedge until the width of the strip was almost 1" - I went to about 1.015", on average - along the whole length, and then straighten that using the optical technique given above.

Similarly, straighten one edge of the small piece. (actually, I was able to use a factory edge of the Plexiglas, so I didn't have to)

I glued up the T-square using epoxy and the jig shown below. Make sure that the edge of the straightedge and the small piece are in contact with the square.

Make sure you clean off the square (using isopropanol [rubbing alcohol]) once the epoxy gets firm.
pfred21 year ago
I like my drawing boxes. Even though my drafting box has a built in drawing board I usually use a separate board to draw on. Usually a half inch thick piece of acrylic. Sometimes I break out one of my drafting tables, but not often.

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