I match my blades with a comm lathe.(not running)
1) Put the prop on a quality shaft & set it down on the v grooves used for the armature shaft. Different spacers with be needed to hold the assembly against one side of the v block so you get a consistant reading.
2) Find & mark the smallest or cut blade. Apply Dykem to the blade you want to cut/trim.
3) Move the X-Y axis and indicate off of the smaller blade so the prop just touches.
4) Rotate prop to the larger blade & mark the Dykem that's on the blade.
5) Remove prop & slowly file the spot that is high.
6) Move X-Y & do again....& again...
You can find used comm lathes cheap on ebay.For big props you might have to mount the v blocks farther away from the X-Y.
I use the corner of the block for an indicator because mine is still used for comms & I don't want to take the bit out.
