3D Printing
Why did I get into 3D Printing?
I got into 3D printing a couple of years ago because my dagger and sword collection hit a critical mass and the only enjoyment I got from them involved periodically taking them out of the closet to clean them. Needless to say, that was not the best use of the blades. I needed to display them, but as all of my blades are sharp, I needed to do so carefully.
I considered wall mounting the weapons. It is a common way to display daggers and swords. However, I have a couple of cats and I would never forgive myself if they ever knocked one off the wall and hurt themselves. This lead to needing an enclosed display case, but then, do I simply lay them down on a shelf (perhaps a glass shelf) or do I find a way to give them prominence?
Google … not quite to the rescue. I figured it can’t be hard to find acrylic displays that would work. Uh, nope. What I found required compromises, imperfect fits, and lots of money.
About the same time, a couple of people at my day job talked their 3D printers and showing off what they made. I quickly ran the numbers and found the Anycubic i3 Mega S printer would cost me less than the acrylic displays I wanted and I could get exactly what I wanted. A bit more searching, and soon I had FreeCAD downloaded. A fair amount of cursing later (it always helps) and I had a working model for my dagger display stands. The version 1.0 of the stand looked similar to the picture above (no rear support and a slightly different notch at the top of the riser).
I printed all the stands I needed, and as you might have seen from some of my prior posts, a few other things. However, what I’ve blogged about is only a fraction of what I’ve created and printed. I spent enough time with the printer, that I sold the Anycubic to someone my wife works with and upgrade to a Prusa i3 MK3S+ and have never looked back.
Don’t get me wrong, you won’t go wrong with either printer, I just started printing so many things, the upgrade made sense.
What has prompted version 3 of the stand?
The simple answer, a set of blacksmithing classes.
I usually get a new dagger or sword each year I go to the KC Renfest and outside of 2020, I have not missed a faire season since the 1980s. My favorite blade smith, John, from Dwarf Mountain Knives has a shop there, and I almost always find something I like (unless he’s sold out of everything by the time I get there). All my blades, except two, are from John.
Well, this year, my wife finally convinced me to drive to Omaha and take part in blacksmithing classes (I took a couple classes many years ago from the Institute for Historic & Educational Arts (IHEA) at the KC Renfest grounds. But in Omaha, I can take a class with Elmo at The Blacksmith Shop and potentially work with John as well.
In talking with John and Elmo, I showed them pictures of my dagger stands and they were interested in seeing them. Well, version 1.0 had some issues, the biggest of which was I had two sizes: a bit too large and a bit too small. The bit too large model suffered from bending near the top as the part aged.
Now that I had a mission, time to get back into FreeCAD and learn some new words to describe the software’s lineage. It really does help.
The next version of the dagger stand needed automatic resizing. I needed to easily change the riser height, move the position of the riser forward and backwards, change the length of the whole base, and adjust the gap at the top of the riser based on the blade width.
That was a long sentence and also a long list of items to get working in FreeCAD as there are multiple primitives that need to move and change with each modification. Google is good for learning curse words.
The good news is, I was able to take the time I needed and learned how to use the Spreadsheet in FreeCAD to set variables and functions to create all the calculations I needed. I used the sin and cos functions to take input for blade length, handle length, and blade width in order to determine the riser height and position, as well as set the overall base length to make it stable. Now with just three entries into a spreadsheet, I can dynamically resize everything. And because I am just that way, I also parametrised everything else, including wall thickness, base width, base height, … I can adjust everything from the Spreadsheet.
Hooray, I’m done!
@#$%. I have blades that yield stands that are too big for my Prusa printer as well.
Okay, time to take the model and pull up a tool to split it in two pieces and quickly print it…
I need to learn some additional languages so I can curse in them. A couple of flat planes don’t have a lot of great bonding strength and can easily snap apart.
Well, back to FreeCAD and learning a new function of splitting a model and keeping everything dynamic. So, now that I can split the model in the same tool and still dynamically resize everything, I just need to join the pieces in a more secure manner, while remaining within the boundaries of what a 3D printer can do (for instance, wide overhangs do not work as molten plastic will droop).
I first modeled some peg holes in the top and bottom of the split and included a set of pegs in the print. Start printing, wait 7 hours… Well, I sized the pegs a little too small (I needed a small gap as the plastic shrinks slightly as it cools, so the holes need to be slightly larger than the pegs when printed). Tried to print just a series of new of slightly larger pegs, but I am still dealing with something only slightly larger than 2 mm in diameter and the print failed as the pegs fell over. Not to mention, I am worried that the small plastic pegs won’t offer enough strength.
So version 3.0 of the dagger stand. This one has a bar and channel to give more space for the glue to bond and should be stronger. Start printing, wait 7 hours, … Success!!!!
So, now I have two new models. A single piece version for smaller blades and the version for larger blades that need to be printed in two parts. I will have to avoid blades that would need this broken into three parts.
I’ve got about 30 hours of printing to finish the remaining prints for the daggers I have (the bigger prints run right around 10 hours each to complete). Then I need to print a few samples to take to Omaha for the classes I have next year. I’ve got plenty of time before the classes, so no rush, but it is great to fix the stands that had warped or snapped in my display case.
Have a happy holiday and next year I’ll share what I learn at the fordge.
Moon set
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