Hi,
Here's a [https://www.boschtoolservice.com/au/en/dremel/spareparts/search-results?q=3000|link] that may help.
Click on the appropriate model number for your Dremel 3000 to view the parts diagram for that model.
You may be able to work out how it's assembled from the diagram.
It also shows the part numbers for all the parts so if one is broken you may be able to find a replacement by searching for the part number.
Just what I'd try.