One end of the 225 t2 is a large receptacle with threads inside and a shaft below the threads.I have no adapter to connect it to the Dremel. The FlexiShaft came with the variable-speed Dremel but no instructions. Right now the shaft is useless.

Model of dremel, battery or mains powered?

You screw off the collar on the tool, remove the chuck and inner part. The chuck is replaced with a special chuck (no inner piece). The special chuck has a square opening in it's nose that accepts the square end of the flex shaft inner cable. Is is actually a speedometer drive cable, from yesteryear.
Then you pull the inner cable out slightly, if it will, and put the inner cable into the square opening of the special chuck on your dremel motor. once engauged, you carefully screw the outer shaft housing on to the end of your dremel motor.
What you want to avoid is damaging this area during flex shaft assembly. I have had success with turning the output side of the flex shaft, while tightening the outer flex shaft onto the dremel motor. Stop tightening if it starts binding...
Rotation seems to help with alignment of all parts.

Cheers,

Doc

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.

Check w/ Home Depot and/or Lowes. If they don't stock they can get quickly

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.

Here's the email from I got from Dremel (in my case the flex coupling broke):
Inside the tool is a flex coupling and spline driver.

The flex coupling is # 2615294309 and the price is $ 1.25.
This is the hollow plastic sleeve about 1" long with grooves on the
inside, that goes between the motor shaft and the output shaft.

The spline driver is # 2615294308 at $ 1.00.
Spline driver sits on the direct end of the motor shaft. The flex
coupling sits over the spline driver. Spline driver is about 1/4",
hard plastic with grooves on the outside.


Total shipping for orders under $ 5.00 is $ 2.50. Orders over $
5.00 is $ 4.00.


I have provided ordering instructions below.

To order by phone: 1-800-437-3635, Monday-Friday from 7 am to 6 pm
central time. VISA, MasterCard or Discover is accepted.

To order by mail:
Dremel
4915 21st Street
Racine WI 53406

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

I dont think it should get that hot. Dremel has a program for the 225 Flex Shaft and for 17.90 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

Do you have a 'nut' on the end, or just a wide open shaft (1/3 inch or so?)
You need a collet nut to tighten bits, and maybe collets of varying sizes also (not sure about this particular shaft).