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Written by Super User

Parent Category: Big Blue Saw Blog

Created: 28 February 2019

How's this for a sweetheart deal? For the rest of the month of February, get free shipping on custom waterjet cut parts. When ordering online, you can get free shipping on any order of waterjet cut parts of $150 or more to anywhere in the US!

Just make sure that you choose "February Waterjet Free Shipping" when you check out to take advantage of this deal.

Upload your designs now to our online quoting and ordering system to get free shipping this month.

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Written by Super User

Parent Category: Big Blue Saw Blog

Created: 23 January 2019

Jay Doscher wrote to tell us about a 3D printer enclosure he created with help from Big Blue Saw. Here's a video with more details:

Here's the designs Jay used on his enclosure front and back panel.

Check out more great stuff from Jay on the Polyideas website or Jay's Youtube Channel.

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Written by Super User

Parent Category: Big Blue Saw Blog

Created: 18 January 2019

FreeCAD is 3D modeling and design software. It is free to use, open source , and runs on Windows, macOS, and Linux. FreeCAD supports importing common 3D file formats like STEP, IGES, and STL.

The latest stable release is version 0.17, released in April of 2018. But FreeCAD's developers have made many advances since then. Pre-release downloads of version 0.18 sport numerous updates, including features to make creating and exporting 2D drawings much easier.

You can download the release and latest pre-release versions of FreeCAD on the project's GitHub website.

Using FreeCAD to view and export STEP files

Let's take a quick look at how to use FreeCAD with Big Blue Saw, starting from a design formatted as a STEP file. The steps shown below were produced with a pre-release version of 0.18, from January 2019.

Let's suppose we have the STEP file with the part pictured above, and want to produce a 2D outline for use with Big Blue Saw's online quoting and ordering system.

After starting FreeCAD, go to the File menu and pick Open. You should select the STEP file to import.

FreeCAD will then show you your STEP file and allow you to zoom, pan, or rotate the view of the part.

Next, we need to switch to FreeCAD's TechDraw workbench in order to create a drawing. Choose "TechDraw" from the drop-down list of workbenches.

You'll notice that the toolbar and menu change to show the features needed for creating drawings. Click the "Insert new default Page" button to create a blank drawing.

FreeCAD will show the new drawing.

 Expand the Model tree on the left and you'll see a sub-menu item called "Template".

Click on Body001, the object representing the STEP file design, in the Model tree.

 And click the "Insert View in Page" button. A 2D view of the design will appear in the drawing.

Now we're ready to create a 2D file. Click the "Export a page to a DXF file" button on the toolbar. You'll see a dialog box that lets you enter a filename and the save location.

The file is then ready to use with Big Blue Saw's online quoting and ordering system to turn the design into a real part.

Here's the finished part waterjet cut from carbon fiber.

Are you a FreeCAD user? Let us know!

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Written by Julie Simancek

Parent Category: Big Blue Saw Blog

Created: 11 January 2019

Custom waterjet cut 3 inch span wrench for BattleBots team Hypothermia

When I’m cutting a set of parts for one of my projects, I often look around the shop for tools or tooling that I can add to the order that would upgrade the shop just a tiny bit better to make it easier to work in. One of my favorite adds to the low taper cut list is custom wrenches. The reason being is that one more part usually doesn’t increase the cost of cutting or shipping too much, and having a designated wrench for changing the lathe tooling that lives with the rest of the lathe tools keeps my wrench set from roaming around the shop in a unorganized jumble.

So let's design a wrench! First we need to identify where the working surfaces are on the recipient of our wrench are. For a hex headed bolt, the working surfaces are the faces that I’ve highlighted in pink below:

Notice that the force lines don’t extend to the convex corners. The reason for that is that there is less material on the convex corners than there is on the centers of the flat faces. If your wrench grabs the corners during use and applies the force there, they won’t hold up to much force before they strip out.

So let’s mock up a crescent wrench to match the hex bolt.

As you can see, we are only applying force to 4 of the 6 faces and if we were to cut the green wrench as shown, it would have to cut perfectly and the hex head would have to be forged perfectly to fit together. Since we are all working within a tolerance range lets add some ease into the places where the faces are interacting to make these work in real life. For starters, we are going to scale our example hex head up by 0.005”-0.01” larger than the actual bolt head. That will allow the crescent to slip onto the bolt without aligning it at the perfect angle.

In the image above, the dotted orange hexagon is the 1” height of my bolt. The black hexagon is 0.01” larger than the bolt head size. That extra room will make it so that my wrench will slip on the hex bolt easier and allow for that bolt to have some variation in size from the perfect CAD model. This is particularly important because the available hardware out there sometimes shifts during stamping or is heat hardened, and all of those factors can affect the finished size of the bolts.

Next we need to address where the wrench is going to touch the corners of the bolt head. As mentioned before, putting pressure on those corners is a fast way to strip a bolt. I hate pulling stripped hardware, so I’m going to add radii to the cutout that will keep the wrench from touching my bolt head.

Those 1/16” circles should keep the corners from getting dinged up nicely. Now to merge them with the larger hexagon. It’s starting to look like a wrench, but I need to adjust the depth that the bolt head slides into the spanner. The corners of the wrench I’ve highlighted below could slip during use and cause stripped corners.

So lets move our bolt head and hole a bit to the right.

Now let's extend the top and bottom parallel faces outward using the line tool to create where the mouth of the wrench will be.

And merge.

Now I just need to cut the green working face shape out of the blue outer wrench shape.

And now it is ready for cutting on the low taper waterjet. Why the low taper waterjet and not the regular one? Because taper in the cut will affect the performance of the wrench and possibly lead to having to dress the working faces. Which would be really difficult for the two faces that are closest to the handle. The low taper waterjet will get you a cut that is as close to 90 degrees through the thickness of the material as possible, leaving much less cleanup. Learn more about taper and low taper waterjet cutting in our FAQ article.

Having a few extra tools and parts in your file library to add to an order to spread out the costs of setup and cutting makes per part prices lower and helps you expand shop tools without a huge investment. There are also a few tools in my shop where replacement parts are no longer available or hard to find, so having a wrench made out of brass or HDPE that will fail before I strip out a specialty setting screw is also handy.

Another view of the Hypothermia wrench

Happy cutting!