Flexure Fractal Vise Jaws

3 min readJan 1, 2024

Overview

I, like pretty much every engineer I know, was absolutely enamored with the idea of fractal vises from the first time I encountered one.

At some point along the way I finally gave in, and decided I wanted to try my hand at making one for myself. But while I do have some basic machining equipment, I don’t want one of these quite badly enough to go that route, so I wanted to find a viable option for a 3d printed, or mostly 3d printed variant.

I tinkered with some concept designs for print-in-place versions, and other printable variants of the same general concept for the classic flavors. But then it occurred to me that the bearings/bearing surfaces could possibly be replaced with flexures that create a virtual pivot along that same line. Below are my attempts to date in testing this out.

If you aren’t familiar with fractal vises, I’d recommend watching one of the awesome videos folks have made (a handful of ones I’ve enjoyed personally are below).

Versions

V5

V4

Shortening the leafs made the two small ‘stages’ to be far too stiff.

V3

This has been the best performing of the four bar designs thus far, but turns out that final pivot for the full jaw is important. Without it, the jaws can’t accommodate an overall wedge.

V2

Worked ok, but I think the lever arm between the contact point and the pivot point is too small. As a result the clamp force has to be quite high to drive deflection into the flexures.