Vertical grooves in cylinder shape

Hi guys! I’m creating the object in photo but I’ve a problem with the vertical grooves. I don’t know how I can do them. Any suggestion? Any plugin? Tks!!

Here you can see the work in progress but without grooves:

First correct the reversed faces on top of the knob and then make it a group or component and ensure it is a solid. Draw a cutter shaped like the groove out at the edge of the knob and use Rotate/Copy to copy it around the knob. Select the cutter geometry and make a group, again ensuring it is reported as a solid. Then use Subtract from the Solid tools to subtract the cutter from the knob.

You’ll probably want to be working at a larger scale because of the potential to create very short edges that would result in holes.

Here’s an example.

Knob with a small cylinder as a cutter.

Cutter shape arrayed around the knob with Rotate/Copy.

Select all the cylinders and make a group. Run Subtract.

Thank you!!!