Introduction: Making a Reproduction Part for an Antique Safe

I am restoring an antique fire safe. The hinge acorn end caps which were made from brass were damaged, or missing. Searching Ebay and Etsy replacements were expensive and many were in poor condition like the parts I had. I received a 3d printer for Christmas and thought maybe I could make replacement part. The first step was to make a drawing of the existing part, then I printed the part, and finally did it look good enough to use in the restoration. The hinge acorn caps look much better than I had hoped for. The last benefit is the caps cost less than a $1.00 in material.

Step 1: Photograph or Scan the Silhouette of the Acorn Hinge Cap

The first step was to get a good silhouette photo of the acorn hinge cap. I choose the least damaged cap positioned it so I had one good side to trace.

Step 2: Tracing and Modeling in Fusion 360

I have been using Fusion 360 software since I needed to make models for the 3d printer. The software is free to use as long as you are not using it commercially.

I will list the steps to create the model for printing. It took about 10 minutes to create this model. I find this very easy to use to make replacement parts. If you have a more complicated item you can use several photos to trace the silhouette on all sides and the top and bottom and you will only have to take a few measurements.

A screen capture of the model is available at this link.


Open Fusion 360

Create a new sketch

Choose the axis to draw on

Insert Attach Canvas

Choose the photo to be traced

Calibrate the canvas image (right click on the image upper left corner)

Measure from the top of the dome to the thread base. (measured the part 1 3/4 inch)

The photo is now scaled to full size.

Now start construction of the model.

Line from the top to the base in the center left to right

Starting at the top

4- Arcs- 3 point (starting at the top center, beginning arc, end arc, pull to fit curve)

3- Lines (base, thread side, thread base to center line)

The enclosed area should turn shaded

Now the silhouette is revolved around the centerline

Then the thread command was chosen and model was chosen so that 7/16-14 would print a complete thread

And you then turn off the canvas and admire the finished part.

Now you choose Make and choose 3d print

This loads the model to Cura the slicing software and opens Cura.

Step 3: Preparing Model for Printing

Cura slicer opened and the model was loaded into the software. The part was rotated 90 degrees for easier printing. The G code is saved to the SD card for the printer.

Step 4: Printing and Painting of the Acorn Hinge Caps

The model was printed. It took about 45 minutes to print each cap. (the first two did not turn out so it took six tries to get four good parts)

The parts were painted with gold paint from a rattle can. And when dry they were threaded into the hinges without any additional machining.

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