I have personally installed similar knobs, screwing them directly into the plug. But it's strange that yours have such a very short built-in screw, so I understand that it becomes difficult.
I have myself installed similar knobs, then screwed them directly into the plug. But it's strange that yours have such a very short built-in screw so I understand that it becomes difficult.
If you absolutely can't make it work, have no idea if the tip about Duotec will work, and your wife can return the current knobs, there are for example Muuto's "the dots" which have a more conventional screw length. You can see them in the picture below. It's also a budget question of course, the package below costs a few hundred. Good luck regardless
Didn't see the picture before I replied. That screw wasn't long.
Fill & fix with the perfo sleeves included should solve the problem. Drill, insert the perfo sleeve, and spray in fill & fix. Then mount the knob when the compound has cured after a few minutes.
250 spänn for fill&fix - soon cheaper with other knobs
Or try to get out the small screw and glue in a longer one.
It can be removed without problem.
Where can I find ones in the same size but longer?
There are threads on one side so I need to find one that's just as short on the side that goes into the knob and then the other end should be significantly longer.
That screw wasn't long. 
