Dremel 7700 Operating/Safety Instructions Manual page 22

Mandrel No. 401 is used with the felt polishing tip and
wheels. Thread the tip on to the screw carefully.
Mandrel No. 402 has a small screw at its tip, and is
used with emery cutting wheels and sanding discs.
The machine-screw threading on Mandrel No. 424
threads into polishing point No. 427.
The felt tip must thread down straight on the screw
Mandrel, and be turned all the way to the collar.
Higher speeds, usually maximum, are best for most
work, including cutting steel. Which is shown here.
This and other threaded mandrels must be screwed
firmly down to the collar before being used.
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