Introduction: 3D Printed Lawnmower Replacement Knob

About: I MAKE in my sleep. I MAKE for keeps. I MAKE I MAKE I MAKE creative me.

I never thought I needed a 3D printer until I got one. Now I would never live without one.

When I started printing, I made a promise to myself to print something of practical use every other print. Once I started looking around the house, I noticed a bunch of items that needed repairs or upgrades. My lawnmower was the first to receive an upgrade. This knob is also the first object I created by myself.

3d printers are pretty affordable these days and for $300 or less, you can get a really reliable machine. I use a Qidi X-one2 that retails for about $300. It came with tools and PLA filament and I was up and printing within an hour of opening the box.

Instructables offers some great classes to advance your 3D printing knowledge. I'd start there.

3D Design

Beginner 3D Printing

Easy 3D Printing


1. 3D printer

2. Filament - I used PLA but recommend ABS for this type of project.

3. Design Software - TinkerCad is free and easy to use. That's what I used.

4. Slicing Software - This usually comes with your printer.

5. Nut and Bolt - Purchased at my local Ace Hardware store.

6. Multi-meter or a good measuring device.

Step 1: Designing in TinkerCad

Designing in TinkerCad is fun and easy. There are great tutorials out there so I'll make mine sweet and short.

I started by drawing the handle I wanted on paper.

I then took rough estimates on the sizes I needed. Measuring included a hex shaped hole for the nut and a round hole for the bolt.

Sign up or enter into TinkerCad it's free!

Now it's really just about dragging the shapes you need on to your workplane in TinkerCad.

I started with a provided STAR shape and got my approximate size.

I then added cylinders to create the "knob" ends.

When you get your shapes into place, it's a good idea to group "command G" your objects together. This glues your pieces into place.

When you feel good about your knob's overall shape and feel, it's time to add the holes for the bolt and nut.

I oversize the holes just a touch to ensure the the bolt fits. Once you have added your holes, group them. This creates the actual hole and is pretty cool to witness. The nut should slide right in and provide a secure hold.

Now your creation is ready to print.

Export your file and save as an .STL file. Now for the slicer.

Step 2: Preparing Your Knob for Print

The slicer program tells your printer how to print your object. You will command it to add supports, infill density, desired temperatures and other actions.

Using PLA filament for the project, I used these settings:

Bed Temperature - 20 degrees celsius

Nozzle Temperature - 220 degrees celsius

Infill - 100%

Support - Yes at 45 degree angle

You can find my project on Thingiverse.

Those are the basics and a short tutorial on 3D printing.

Have fun and feel free to ask any questions.

Fix It Contest

Participated in the
Fix It Contest