New old stock faucet style Knob for locking the belt tracking. 

The coarse thread matches the early models tracking adjustment shaft.

Also secured the Idler Drum Cover for 6 x 48 inch vertical Belt Sanders.

Later models after serial # dx-332 used fine thread knob 406-03-100-0001.

If you are doing a restoration this is the one to use.

Also the Table Tilt Lock Knob for many Delta and Rockwell 14 inch Band Saws.

Make sure to check the picture for style verification!