Using the flex shaft attachement.

Don't know what type trimmer you have but many have a bell housing with long sleeve that the shaft fits in. You have to remove flex shaft and look inside the sleeve there is a Allen head or star head screw in center these normally turn ccw to remove but some turn cw.

curved shaft trimmers use a flex drive in side the case so that it can drive around the bend of the case
they are held in line with bushes spaced along the tube and this prevents the flex drive from binding back over itself
from your description of the problem, pull that flex drive out of the case and check for signs that it has a problem
the problem with bent shafts is that they will not handle any sort of a load and therefor are not suitable for heavy growth, heavy trimmer line or any metal/fixed attachments
the heat in the case will be from the flex drive rubbing on the inside of the case

Use a piece of wire with a right angle hook on the end Push the wire down until it is inside the spring lever sideways and pull out.

find the little square attachment and place on the end of the dremel tool. I didid the same thing. Worked fine after I put the other part on.

To use the flex shaft, you need to remove the bit collet. Included in the kit is a nut looking item--mine is silver. It has a square end and screws on to the end of the dremel. It is simlar to the collet, but is slightly smaller. Then you place the square end of the flex shaft into the nut and screw the shaft on to the dremel.
Hope that helps

You remove the bit you were using and connect using existing collet, just tighten and go.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/matt_8dbc24bf722649ac

Takes an adapter to screw onto the nose of the Dremel. The shaft itself is gripped by the correct size collet tightened as you would any bit.

Sounds like you'll need to either order a new flex shaft from Worksmith, or purchase a different rotary tool kit. Dremel makes the best, and Central Electric (Harbor Freight Tools) also makes a flex-shaft kit.

There are no manuals I have found but I have a website and phone number for them the site is Dremel.com and the toll free number is 1-800-437-3635 you can use either one to get the manual you need.

Dremel has an exchange program for the 225 Flex Shaft. Send your flex shaft and 17.90 and they will exchange it for you. Send it to DREMEL 4631 E. Sunny Dunes Rd. Palm Springs, CA 92264 Their phone number is 1-800-275-2052. Hope this helps. Dave