I had posted a shorter version of this on one of the Facebook groups a few weeks back, and I thought I would share it here for anyone with an interest... Mods: If this fits better somewhere else, please move it.
If you're anything like me, I hate wasting time. I also hate spending time on something that can be done in a much easier way; think of the mantra, "Work smarter, not harder". I am applying that to making knife and sword blanks. And if you're like me, this will result in a cleaner blank (my cuts with a grinder look like a preschooler trying to stay in the lines).
Below I will should you how to make a knife blank from a picture you sketch out or pull off the internet.
Here are a few disclaimers:
- This is a free way to do it. I am sure there are software programs that will do it easier, but I like free stuff. And what you buy today will be open-source in a year anyways.
- I won’t go into using all these programs unless it is necessary for this quick tutorial. Just trust me when I say you can learn them easily…
So here we go…
There are basically 4 steps and I will go into details on each one:
Step One – Get a black and white picture
Step Two – Get it to a SVG file
Step Three – Edit and Save in TinkerCad
Step Four – Convert to DXF/DWG
Step One – Get a black and white picture
The first thing you have to do is find a picture of the object you want to copy. It will make your job so much easier if the picture is high contrast, meaning the object is dark and the background is light. You are looking for a pretty clean edge, or as sharp as you can find. Sometimes I will do a very specific Google image search and find the best one. You also want a picture that is taken from the top of the object as opposed to the side. This minimizes distortion. Here is what I will start with:
Once you have selected the picture, you need to turn it to a simple black and white picture. You’re not looking for shading, you’re looking for a crisp outline. Remember, you’re not looking for your bevels or anything, you just need the lines of the outer edge. To get to a black and white picture, there are a number of online sites to use. Two of my favorites are picmonkey and fotoflexer. You can also use the Paint program that comes standard on Windows computers. If you have questions about the specific ways to do this, let me know. You just need to get the image to a black-and-white JPEG. This will take you about 10-15 minutes for a knife/machete.
Step Two – Get it to a SVG file
So once you have an outline, you need to transfer it to a SVG file. Well, you don’t need to, but I like to. An SVG file is a file type used by 3D printers and you can easily make changes to them with a free web-based program called Tinkercad.
To get your JPEG to an SVG file, you go here:
image.online-convert.com/convert-to-svgYou simply select the image file you want to convert, and can also use some custom settings. I typically click on “equalize”, “sharpen” and “enhance”.
You will then be able to save the SVG file to your computer.
Step Three – Edit and Save in TinkerCad
Now you can start having some fun and actually begin to edit your design… You will need a free TinkerCad account to use their stuff, but it is worth it.
When you import the design, remember three things:
1) The quality of your input is going to be influenced by the quality of your black-and-white pic from step one. If you have poor edges, go back and clean them up a little bit.
2) Be prepared for your design to be a funky size. All of the dimensions will get ok, but the design could be much larger than anticipated. All you need to do is click on a corner while holding ”shift”: this lets you change the size while locking the overall proportions.
3) You can adjust the width of the material.
So when I imported the example above, it came in really large (it was supposed to be 9" but came in at over 20"):
You can easily change the size of the hatchet and move the object to the center of the workspace:
You can also set the thickness of the item by doing the following:
TinkerCad makes it easy to group parts, add pin holes/lanyard holes in the handle, etc. I will also use this part to print a quick test of my handle with my 3D printer (I would rather waste filament than steel).
To get to this point, you maybe have 20 min of time invested...
Now most people who run a waterjet have the software to easily convert an STL to DWG file. If you need to convert it yourself, you can do the following:
www.instructables.com/id/Convert-STL-to-DXF-using-Open-Source-tools/Now, where can you get this stuff cut? If you look around online, you can usually find someone local to cut for you... They may have a minimum that makes a single blade cost-prohibitive (sometimes they have a min rate they charge). I had these 4 blanks cut locally for around $100, not including the $60 I paid for the 5160:
Now, if you need someone to cut, I recommend a guy names Keith. He has by fair the most reasonable prices I have found both locally and online... He has no hourly minimum and will order any material you want. To give you an example, he cuts 8" discs for me (for a business application) and charges $7 including steel. A small 5" blade runs a a few bucks if you send the material. Keith can be reached at keithg222@gmail.com.
Here is a test blank he did for me:
Hope you find this helpful!