Installing heat-set inserts for 3D printed drawer pull knobs
Channel: Bradford Needham
Date: 2019-10-19

I designed 3D printed drawer pull knobs for the clockmaker's bench that I'm creating. Like many knobs, each of these knobs will screw onto a bolt that goes through the front of a drawer. To make the knobs hold well, I decided to press a threaded, heat-set insert into the back of each knob instead of using relatively weak, 3D printed threads.

In this video I show how to press a heat-set insert into a 3D printed part, using a soldering iron.

A nice Hackaday article on desiging for and installing heat-set inserts: https://hackaday.com/2019/02/28/threading-3d-printed-parts-how-to-use-heat-set-inserts/

The installation tip(s) for my soldering iron. Not exactly for a 1/4 inch insert, but it works for me: https://smile.amazon.com/gp/product/B078K72615

The drawer pull knob design is open-sourced on Cults3D: https://cults3d.com/en/3d-model/home/gear-themed-drawer-pull-knob-using-1-4-inch-heat-set-insert

The Heat-Set Inserts for plastic, for a bolt with 1/4-20 threads: https://www.mcmaster.com/94459a370

The matching 1 3/4 inch bolts to fit my bench drawers: https://www.mcmaster.com/91772a548

The "Fixture" I keep referring to in the video is simple: it's a stand-in for the front of the drawer I'm going to screw the knob into: it's a piece of wood - in this case 1 and 1/2 inch thick, with a 1/4 inch hole drilled straight into it. Just 1/4 inch of the bolt protrudes from the wood so that I can screw the knob flat into the face of the wood. As I explain in the video, this simple fixture makes the heat-set insert nicely perpendicular to the face of the knob. The fixture looks more complex just because it's a piece of scrap wood that has other holes in in.

The parts are SAE rather than Metric because 1/4 inch is a very common bolt diameter where I live.