From the Loftsmith Workshop

Screw nutcracker sized for walnuts, hazelnuts and pecans

Cracks a walnut without the shower of shell bits or the bruised thumb. Drop the nut in the cup on the wide base, then turn the winged knob down until it gives. The big wings give your fingers plenty to push on. Change the biggest and smallest nut sizes to suit your haul.

2 parts · 48 g · 70 × 70 × 126 mm

by Loftsmith Workshop

Red nutcracker base with a threaded cream screw and a wide wing knob on top
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No adjustable sizes

Ask for the sizes you want to tweak, e.g. “make the width adjustable”.

Change it in the Studio

Parts

  • body · PETG · Upright, foot on the bed, as shown

    70 × 70 × 76 mm at the defaults, ~33 g, ~53 min (2 walls/15%). The internal thread runs around the layers; the window arch and thread flanks are 45°, so no supports are needed. PETG for toughness under a sudden crack.

  • screw · PETG · Upside down: flat top of the wing knob on the bed, thread pointing up

    64 × 34 × 72 mm at the defaults, ~15 g, ~30 min (2 walls/15%). Wing knob, 22 mm two-start thread and a rolled ring tip. Its length is set by the Smallest nut slider. To change the stop, reprint only the screw; the body stays the same.

Print settings

Layer height
0.2 mm
Walls
4 (the page stats use 2)
Infill
20% (the page stats use 15%)
Supports
None
Notes
At the page defaults (2 walls, 15% infill) both parts take about 49 g and 1 h 25 min. For a stronger thread and legs, 4 walls and 20% infill are recommended: about 80 g and 2 h 20 min. PETG is recommended; PLA prints the same but is more brittle when a shell gives way suddenly. If the screw is stiff

Assembly

  1. Print the body upright and the screw knob-down. Both print without supports.
  2. Start the screw in the countersunk top of the body. It is a two-start thread, so either start catches. Turn clockwise; the thread advances 10 mm per turn.
  3. Turn the knob anticlockwise until the tip is up near the top of the window.
  4. Round cup: lift the nut over the seat rim, slide it in through the window and drop it into the cone. Long cradle: lay the pecan in the V groove from the front; it can stick out front and back.
  5. Hold the body by the fluted legs and turn the knob clockwise until the shell cracks. The knob stops on the hub before the tip can reach the seat.
  6. Back the screw off and tip the shells out through either window.

Good to know

  • Cracking force and wall strength are not checked. Printed threads can strip on very hard walnut shells, so it is not guaranteed to crack every walnut.
  • The pull from cracking runs up the legs across the print layers. Print with good layer adhesion (PETG, not too cool) and stop if you hear the body creak.
  • The stop is fixed by the Smallest nut slider: the knob lands on the hub after the tip has squeezed that nut by 30% of its diameter (4.8 mm for 16 mm). It is not adjustable after printing; reprint just the screw to change it.
  • The thread fit depends on your printer. The default 0.25 mm per flank is a starting point, so check it with a tolerance tester.
  • For pecans, choose the long cradle and set Largest nut to their width (pecans are roughly 16–24 mm wide), not their length.
  • Not certified food-safe. Only the shells touch it, but wash it before use and don't use it for food prep.
I printed this Remix

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