3D Printed Hinge Design

Want to add a hinge to your design? I'll walk you through a simple hinge design that you can add to any of your prints.

What you will need:

  • Small bolt & nut (I'm using a hex cap #8-32 x 3/4")
  • Calipers (optional)

Let's start off with modeling the bolt and nut. I measured the across-the-corner dimension of the hex (.375") and made a hexagon accordingly. Extruded that shape (.125") for the nut and bolt head. I modeled a cylinder (0.8" L X 0.164" D). In this instance I used the major diameter. Then I cut a hole in the nut with my cylinder. 

There is another, easier way to do this if you don't have calipers. The great people at McMaster-Carr have modeled the majority of everything on their site. This is a great resource, but please use responsibly.
Here is a link to the bolt I used. 
Here is a link to the nut I used. 

You can see how much more detailed their (right) model is than mine (left).

Now we need our hinge. I'm borrowing from the 'lift off' style hinge design.
We will start off with a tube. Our ID (Inner Diameter) will be determined by this chart. Find your 'Screw size' in the leftmost column and follow that row over to the 'Clearance Hole' column. You will want to select 'Free Fit'. In this case our hole will be 0.1770". Since ABS tends to shrink after printing, I'm going to round up to 0.18" just to be safe. 
Now we need to determine our OD (Outer Diameter). I have found through experience that anything less than 0.1", in thickness, is not very strong. We are going to add 0.1" to the radius, or 0.2" to the diameter, so 0.18" ID + 0.2" = 0.38" OD.
Next we need the height, about half the shaft of the bolt. For my bolt that is 0.8", but we still have to thread on the nut (0.125") and have at least a few threads showing (2 x 32 threads/inch = 0.0625"). So (0.8" - 0.125" - 0.0625")/2 = approx. 0.3".

Now we can attach our hinge to our part. For this example I just attached it to a simple box. Make sure whatever you are attaching to doesn't overlap the hinge. This will cause interference with the opposite hinge. I have to cut away a portion of my box. Since this is symmetrical we can print a copy for the mating hinge. You will also want to position your bolt and nut in place to check for interference.

 

As you will recall from the how to print a cylinder post, we will want to print our hinge cylinder vertically.

And below we have the final results. I had to use a split lock washer to prevent the nut from backing off when rotating the hinge.

This is just a brief intro into hinge design. In the future, depending on what ya'll want to see, I may do another post about integrating different designs into your print.

Thanks for reading, please like and share if you enjoyed this.

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