I've modified and fixed IKEA products in the past and this clock was no different. The clock itself costs $5 and overall, it's a great value. The motor mounts are steady, parts are reliable and the clock has worked for years. However, it's very clear that to cut costs, IKEA designed the knobs to be as small and flimsy as possible. Both of my knobs broke and caused a rattling sound inside the clock. I felt like it was such a waste to have such a crappy knob on such a good product. So I made them better.

I recommend printing the knobs in black. I ran out of black after printing the first knob, so I printed the alarm knob in red. It printed beautifully and the print quality, as well as the ribs on the outside make it feel higher quality than the stock knobs. Even if they aren't broken, I highly recommend replacing the stock knobs with these. They're taller for better grip, and they just feel better in the fingers.

Print Settings

Printer Brand:

Creality

Printer: 

Ender 3

Rafts:

No

Supports: 

Yes

Resolution:

0.2mm Layer Height

Infill: 

30%

Filament:
PLA

Black & Red Hatchbox.
 

Notes: 

If you print with a 0.45mm extrusion width, you will be able to print with 3 shells. I highly recommend printing with 3 shells.

Post-Printing

Removing the Included Support Material

The knobs require supports. You can either use my supports (you must print with <0.25mm layer height in order for them to separate) or generate your own in your favorite slicer by using the support free model instead.

To remove the ring support on my model, I recommend using a pair of side cutters to grip the rim of the support (as shown below) and then to pulling down to separate the support from the rest of the body.
You could also tap the support lightly with a small hammer while rotating the knob. The support should break off after a series of very light taps. Take your time and make a series of light hits rather than a few heavy hits.