You're buying the Rosewood front knob shown in the photos.

This knob measures approximately 1-3/4" wide at the top. The height is just over 2".

The threads on the screw accept a 1/4- 20 nut.

The origin of this knob is unknown, as shown it has a single threaded screw for attachment.

Possibly Union or other manufacturer.

This knob was lathe sanded, and given two coats of clear shellac.

Make sure this knob is compatible with your plane before purchasing, as I cannot guarantee a particular application.