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Step 5Screw-Together Design
The final design that I investigated used miniature screws to aid in construction. The premise was to laser cut the pilot holes on the face, and then drill and tap the end of an adjoining face. See the first two pictures for a 6mm Eurolite ply wood cube using this technique. The third picture shows 6mm black acrylic pieces ready to be assembled.
I used 2M screws that were 12mm long so that they would embed half their length and fasten/ratchet against the face with the pilot holes. I found that using a 1.5mm drill bit I could screw into the ply wood and the hold was rock solid.
The video below shows the process sped up a little. I used a rotary tool, but I also experimented with a cordless drill and found them both suitable for the job.
SUCCESS!
Construction is fast, and 100 stainless steel miniature screws will only set you back $5-$10 depending on the exact specifications.
Constructing an acrylic cube proved to be quite difficult. I attempted construction in the same way as the ply wood cube, but the tapping was hit and miss.
Without a drill press it is quite easy to elongate and misshape a hole in acrylic, and tapping a misshapen hole provides very little hold. The other problem is that the acrylic is heavier and slides around more then ply wood (a jig instead of tape would have been better to hold the pieces together). I've drilled and tapped a variety of materials with hand tools, but never as small as 2M screws (which was my undoing). Picture 4 shows a snapped drill bit and a snapped tapping tool.
FAIL!
Instruction 5a: Evaluate the tools required for construction, and whether common or specialist tools are needed. Material choice can make a big difference.
I decided to try again with the acrylic cube (I had laser cut a spare), and this time just drill a 1.5mm hole and try fastening without tapping. To do this you need quite a bit of force, and if using miniature screws you need a fine tapered screwdriver. For the cheese head screws I was using, my multi-tool was perfect - sort of (see picture 5).
FAIL!
Instruction 5b: Thou shalt not self harm.
I did finally get the acrylic cube together (see picture 6), but I wouldn't describe it as successful (gaps and faces not quite square to each other). I wouldn't go down this road again without a jig and drill press.
In terms of cost, laser cutting for this design was the cheapest of all ($1.57 USD* using square holes, or $1.90 USD* using round holes). Cost per screw is 5-10 cents; 24 screws per cube is a little bit of overkill. (*pricing on 1st August 2008 for "making" costs using 6mm Eurolite ply wood).
Instruction 5c: Curves take more time to cut (and thus cost more) - don't use curves where they wont be seen (like when they are covered by the head of a screw).
Construction time with ply wood was negligible, just a few minutes to drill all the holes, and then a few more minutes to fasten the screws. Acrylic took forever. The actual design was very quick and no fitting was required in Inkscape because everything was joined with screws.
Aesthetically, I think that ply wood and metallic screws could be used to make some steampunk inspired creations. I don't think that acrylic is worth the effort with this design unless there was an underlying need for the material (e.g. moisture resistance).
To end on a good note, compare the original SketchUp design (picture 7) with the ply wood cube.
SUCCESS!
The SketchUp->Inkscape->Ponoko pipeline works once again.
I used 2M screws that were 12mm long so that they would embed half their length and fasten/ratchet against the face with the pilot holes. I found that using a 1.5mm drill bit I could screw into the ply wood and the hold was rock solid.
The video below shows the process sped up a little. I used a rotary tool, but I also experimented with a cordless drill and found them both suitable for the job.
SUCCESS!
Construction is fast, and 100 stainless steel miniature screws will only set you back $5-$10 depending on the exact specifications.
Constructing an acrylic cube proved to be quite difficult. I attempted construction in the same way as the ply wood cube, but the tapping was hit and miss.
Without a drill press it is quite easy to elongate and misshape a hole in acrylic, and tapping a misshapen hole provides very little hold. The other problem is that the acrylic is heavier and slides around more then ply wood (a jig instead of tape would have been better to hold the pieces together). I've drilled and tapped a variety of materials with hand tools, but never as small as 2M screws (which was my undoing). Picture 4 shows a snapped drill bit and a snapped tapping tool.
FAIL!
Instruction 5a: Evaluate the tools required for construction, and whether common or specialist tools are needed. Material choice can make a big difference.
I decided to try again with the acrylic cube (I had laser cut a spare), and this time just drill a 1.5mm hole and try fastening without tapping. To do this you need quite a bit of force, and if using miniature screws you need a fine tapered screwdriver. For the cheese head screws I was using, my multi-tool was perfect - sort of (see picture 5).
FAIL!
Instruction 5b: Thou shalt not self harm.
I did finally get the acrylic cube together (see picture 6), but I wouldn't describe it as successful (gaps and faces not quite square to each other). I wouldn't go down this road again without a jig and drill press.
In terms of cost, laser cutting for this design was the cheapest of all ($1.57 USD* using square holes, or $1.90 USD* using round holes). Cost per screw is 5-10 cents; 24 screws per cube is a little bit of overkill. (*pricing on 1st August 2008 for "making" costs using 6mm Eurolite ply wood).
Instruction 5c: Curves take more time to cut (and thus cost more) - don't use curves where they wont be seen (like when they are covered by the head of a screw).
Construction time with ply wood was negligible, just a few minutes to drill all the holes, and then a few more minutes to fasten the screws. Acrylic took forever. The actual design was very quick and no fitting was required in Inkscape because everything was joined with screws.
Aesthetically, I think that ply wood and metallic screws could be used to make some steampunk inspired creations. I don't think that acrylic is worth the effort with this design unless there was an underlying need for the material (e.g. moisture resistance).
To end on a good note, compare the original SketchUp design (picture 7) with the ply wood cube.
SUCCESS!
The SketchUp->Inkscape->Ponoko pipeline works once again.
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