Hex Deburring Tool: Click-In Swivel Blade, Blade Storage with Magnetic Cap

A deburring handle built to print the strong way. The body is one piece that lies on one of its hex flats, so the layer lines run the full length of the handle. No supports, no split halves, no glue, no threads.

The blade pushes in from the front and clicks into place, then swivels freely like a commercial handle. Pull it out firmly to swap it. Spare blades ride in the handle behind a magnetic end cap.

What makes it work

• Printed spring catch. A thin finger is cut into the side of the nose, attached only at its rear end. A small round bead on its tip snaps into the groove on the blade shank. The bead sits in the groove without pressing on it, so the blade spins freely.

• Prints flat with no supports. Nothing on the body overhangs past 45 degrees. The longest bridge is 5.8 mm, over the storage cavity.

• Strong where it matters. Upright-printed handles tend to snap at a layer line. Here the layers run along the handle, and the catch finger bends along its layers too.

• Hex body. It won't roll off the bench and gives your fingers a positive grip.

Blades

Fits standard 3.2 mm (1/8 in) swivel deburring blades with a groove in the shank, BS1010 / S10 style. Push the shank into the nose until it clicks.

Surprisingly handy for

• Cutting the foil safety seals under the caps of pill bottles and jars; run the hook around the rim and it comes out clean

• Elephant's foot and sharp edges on 3D prints

• Cut edges of acrylic, PVC pipe and other plastics

• Flashing on molded plastic parts

• Many other unexpected applications where it happens to be the perfect tool!

Hardware

• 2x 6x2 mm round neodymium magnets

• A couple drops of CA glue

Assembly

1. Stack the two magnets together and mark both outer faces with a marker.

2. Glue one magnet into the pocket in the cavity floor, 5.5 mm in from the rear, marked face down.

3. Glue the other into the pocket on the cap's spigot, marked face down.

4. Line up the dot on the cap with the flat opposite the two slots on the bottom, and slide it in. It clicks when the magnets meet.

5. Push a blade into the nose until it clicks, then flick it to check it spins.

Printing notes

• Print the body on the flat with the two small slots facing down. Those slots free the spring finger; they aren't a defect.

• Turn on elephant-foot compensation (0.1 mm is what I did, which seemed to work well). The finger stands on the bed between 0.8 mm slots, and a squished first layer can weld it in place. If it comes out stiff, run a hobby knife through the two slots.

• Tested in both PLA and matte PETG, and both work well. PLA gives a slightly crisper click; PETG is the tougher choice if you want it to last for years.

Nerd Corner: Fine-Tuning the Click

The handle can be regenerated using hexknife_script.py (Python script; needs pip install manifold3d trimesh numpy). Edit the numbers at the top and run it to get new STLs. The ones that matter: