Case Study: 3D‑Printed Soft Jaws Accelerate Prototype Production at Superstition Machine Works

3D‑Printed Soft Jaws for Rapid Prototype Manufacturing

By day, Rob is a mechanical designer at a machine shop that specializes in industrial handling chutes and processing equipment. He creates 3‑D models in Inventor and generates CAM programs in HSM 2016.

By night, Rob builds RC car parts that he sells online. Over the past eight years, more makers and product designers have approached him for quick‑turn prototyping services. He decided to formalize the business, acquired the necessary machinery, and launched the Superstition Machine Works Facebook page.

First Machine – A DIY CNC Mill

The shop’s inaugural machine is a self‑made CNC. Rob converted a Grizzly G0704 drill/mill into a full‑featured CNC mill. He notes, "I had never used anything more advanced than a drill press, and I am completely self‑taught in CAD, CAM, machining and CNC design."

The auxiliary router, now attached to the spindle, can reach up to 27,000 rpm and has been used to cut 0.020‑inch wide, 0.030‑inch deep slots in 6061 aluminum.

Rob currently employs a homemade quick‑change fixturing system on the table.

Second Machine – MarkForged Mark One 3D Printer

To manufacture high‑end RC car components, Rob purchased a Mark One. "I’m already drawing the soft jaws in CAD, so loading the file into Eiger takes far less time than setting up toolpaths manually," he explains. "Since my tools are manual, hours would be spent configuring the setup."

Rob initially saw the printer in a machining forum, then again in Modern Machine shop, and decided it was a viable investment after reading the article "One‑Offs Without Trade‑Offs."

3D‑Printed Honeycomb Panels, Rod Ends, and the First Soft Jaws

Before the soft jaws, Rob produced carbon‑fiber‑reinforced keychains, fiberglass honeycomb panels, and a set of rod ends showcased on the Superstition Facebook page. The soft jaws marked the first custom fixture he printed.

The jaws were designed to drill two holes at unconventional angles on a part’s second operation.

Installed on the vise, the soft jaws replaced an old metal fixturing system. The device completed a production run of 32 prototype light‑housing components, drilling precise holes for LED wire exits.

"It Also Worked Perfectly"

Rob reports, "Not only does it look good, but it also worked perfectly. All 32 parts cycled with no issues; the last one fit as well as the first."

Resources and Downloads

• For custom RC parts or prototyping services, contact Superstition Machine Works on Facebook.
• Read the Modern Machine Shop article, One‑Offs Without Trade‑Offs.
• Need a 3D printer for your own soft jaws? Call or email the MarkForged sales team.
• Download the soft jaw STL file here.
• Download the soft jaw MFP file here.