Introduction: Pentominoes in a Case
This is a set of Pentomino pieces in a handy carry case with swivel top. I designed it a few years ago after reading 'Chasing Vermeer' by Blue Balliett in which the main character solves a crime with the help of pentominoes. It's Nintendo DS size and a clear cover prevents the pieces from falling out.
The files to laser cut this project can be downloaded from www.thingiverse.com/thing:5038 . One of the files is in *.dtd format for direct use in UK schools where Techsoft 2D Design is widely used to laser cut.
Step 1: Make the Pentominoes in a Case
There are 2 layers of 3mm and 1 layer of 2mm acrylic. The surround of the Top layer is bonded to the Base layer with thin acrylic cement, e.g. Tensol 7. An M3 lock-nut is inserted from the very bottom and held in place by an M3 countersunk fastener that also allows the clear cover to swivel.
2 @ acrylic 120 * 80 * 3mm (appr. 5" x 3" x 1/8" ) coloured
1 @ acrylic 120 * 80 * 2mm (appr. 5" x 3" x 5/64" ) clear
M3 lock-nut & 10 mm M3 countersunk machine screw (appr. 3/8")
thin aluminum/brass rod
thin acrylic cement
Drill Press Files
! Download the files to laser cut this from www.thingiverse.com/thing:5038 !
- Measure the thickness of your stock material. Not all 3mm acrylics are 3mm and some shrink more than others when lasering. That's important here when matching the holes to the aluminium rod to be used as registration points for glueing and as retainers for the clear swivel cover. So measure their diameter first. For the clear cover 2mm acrylic is more elegant than 3 mm and flexes better when swivelling over the pins.
- Measure the diameter of your pins and do a test piece to make a matching hole that is tight. The design features 2.3mm holes which you could enlarge by drilling. Change the hole diameter in the design where necessary. A tight fit is needed.
- Set the height & apply your settings (see screenshot) and then cut the 3 mm layers.
- Adjust the height and cut the 2 mm clear acrylic for the cover, then countersink the hole larger hole carefully to match the fastener (drill press / hand countersink tool)
- Cut the aluminium pins to size allowing them protrude about 1.5 mm, so about 4.5 in total, then file one end flat and the other domed. You could also use brass (hack some motherboard for terminals)
- Place the surround onto the base and secure it with the aluminium pins. Insert the 3 mm lock-nut and pass the M3 countersunk fastener through the surround and screw into the lock-nut.
- Using a fine brush or cotton butt, apply acrylic cement to the outside edges where the layers meet and let it go in between by capillary action.
-After a minute or so you can unscrew and then fit the clear cover. Do not overtighten your fastener. Mark how much is stick out the bottom, remove and shorten with a hacksaw. File smooth and refit.
(At this stage you should still be able to adjust or replace the aluminium pins provided they aren't glued in. They can be driven out with a nailpunch or a blunt wire nail.)