Laser cutter swatches

Laser cutters can engrave or cut through a variety of material so it's important to keep a log of the settings for each. Often times the settings are the same and you'll only see a slight variation, and other times you'll see differences on the same piece of material. Plywood, for example, can offer slight variations depending on the amount of glue used. Corrugated cardboard is often not completely flat or has different-sized air holes inside.

I spent the better part of a day creating swatches for the different kinds of raw material we have in the Makerspace. Hopefully I can mount them to posterboard and leave it next to the laser cutter so other users can benefit.

The swatches have information and test patches of depth percentage and speed, the two settings that have the most impact on engraving. If I planned a bit better I could have included space for score and cut settings -- although this probably would only be beneficial to see if the laser cut through the material, which would mean the last setting is the only important one.

Laser cutting topographic maps

I've added another project to my current assortment of a DIY coffee table, Breakout boxes, and pot lights at home: laser cutting a 3D elevation map of Vancouver. You can often see this wooden maps at craft fairs and they take a fair amount of work: you have to extrapolate the elevation data from maps, create a 3D vector-based file, accurately scale it to the thickness and size of your material, then assemble it, typically gluing all the nested elevation layers one by one.

It's quite a bit of work and I've stopped and started numerous times. I am also definitely not a great geographer, so a lot of the GIS and elevation data is a bit confusing to me; I'm not even sure what the difference is between topographic, elevation, digital elevation, and contour maps! But I've somehow made it a point where I can start assembling my first prototype. Here is the 3D file I've created so far of Vancouver:

I had to exaggerate the hills a bit so they contrast more with the flat areas but I'm really happy with what I have so far. There's quite a few different ways to get this point, so here are some of the links I used so I don't forget:

• http://www.meshmixer.com/
• http://www.meshlab.net/
• https://www.autodesk.com/products/fusion-360/overview
• https://apps.autodesk.com/FUSION/en/Detail/Index?id=8699194120463301363&appLang=en&os=Mac&autostart=true
• http://jthatch.com/Terrain2STL/
• https://data.vancouver.ca/datacatalogue/contour.htm
• https://opentopography.org/
• https://qgis.org/en/site/
• https://apps.gov.bc.ca/ext/mtec/public/products/mapsheet
• https://www2.gov.bc.ca/gov/content/data/geographic-data-services/topographic-data/elevation/digital-elevation-model

Doing a jig: followup

I picked up some of the 1/4" copper couplings from Home Depot and tried inserting them into the 3D printed pocket hole jigs. The hole is quite a snug fit, so I tried heating up the copper with a soldering iron (actually a woodburning iron but technically the same) and sliding it in. I completely melted the interior shaft of the first jig! I guess I held the iron to the copper too long and it got much too hot.

The subsequent ones worked fine, though I found it was sometimes easier to run the drill bit through and grind the spinning coupling into the plastic. Once it was in I heated it up a bit to try and get a press fitting. I also received the four 3/8" drill bits from Amazon, but unfortunately one was missing the set screw on the collar so it was pretty much useless to me. I printed off a return label and will post it back tonight.

I tried out the DIY jigs in class today and they worked well -- for a little bit. For the most part they held up but one jig got destroyed when the drill went in on a funny angle. Two or three more had the copper coupling fall out; I re-seated them with the soldering iron and they seemed to last the rest of the block.

Overall, I wouldn't do it again just to save money. The Kreg jig is much sturdier, perhaps because the coupling runs the entire length of the drilling shaft or maybe the plastic is a bit tougher. And since one of my new drill bits was missing it's collar due to the set screw I was also down one station. Much easier just to buy the package all together and you know it all works.

Doing a jig

I've been using the Kreg K4 jig to make pocket holes recently. I'm pretty new to using such a jig and it's worked out really well. It's easy enough for our woodworking students to use but still challenges them to consider hole placement, depth and final appearances when filling with dowels or putty. Unfortunately, the K4 is quite expensive at around $130 regular price. There are cheaper versions, but they typically require clamping and move around a lot.

Since we typically have 15 students all requiring the jig at the same time I tried shopping around for cheaper version. I turned to Thingiverse and found a few different jigs. I printed out this one and found some 1/4" copper couplings at Home Depot to insert. The couplings should help guide the drill bit and protect the plastic from damage, similar to how the Kreg jigs work. I'd like to attach a vertical support on either end to help with clamping and alignment.

For the drill bits, I ordered some 3/8" bits with stop collars from Amazon. The reviews are a bit mixed on the durability and quality of the step screws on the collars but for $11 each I'll give it a try. I'll have a total of 6 3D printed jigs, 4 extra drill bits, the Kreg K4 and a smaller R3 jig. My 3D printed versions and Amazon drill bits are basically DIY versions of the Kreg Jig Mini sold for around $27. Plastic filament works out to be about $1.50, drill bits and stop collars were $11, and the copper couplings were $1.15 each. So a total savings of about $14 each, or $56 in total. We'll see if they work!