Best / easiest way to mortise a door frame?

[chrisntam]

I need to install a couple of Door Bulls (door security device) at my mom's house.  The frame plate is about 4 inches tall, I have to mortise it in so it is flush with the door frame.  

I have chisels, small hand held router, dermal tool, etc.  What's the easiest way to mortise in the frame plate (pictured below) after I trace the outline?.  I'm relatively handy, but figured I'd ask here rather than struggle with it.  It'd be like mortising in door hinges to the door frame.

Thanks in advance.

chris.

[EightFingers]

How’s that work if there’s a fire?

[fredhargis]

I think I'd take the door off the hinges and cut it out with a router. Square it up with a chisel if needed.

[chrisntam]

The frame plate attaches to the latch side of the door. The lock part slides into the groove of the frame plate. The sides of the lock rest against the door and door trim/frame. The door is now locked. In the event of a fire or to exit just lift the lock out of the groove and open the door.

[museumguy]

I think I'd take the door off the hinges and cut it out with a router. Square it up with a chisel if needed.

This. Seems like the best approach.

[Roly]

This. Seems like the best approach.

Except the frame needs routing out not the door.  Roly

[srv52761]

Trim router, top bearing flush cutting bit.  
Some  mdf  along the outline of your mounting plate on the jamb and casing, building up to the appropriate height.  Depending on the style of casing, you may need to shim one side to keep it parallel to your door.  Chisel to clean up the corners, although after watching the video it looks like the corners next to the door stop are radiused.

To attach the mdf use double sided tape or the  Wood Whisperer’s no double sided tape method
I have pulled paint off with double sided tape.  If you have touch up paint a pin nailer would work.

Stop using double sided tape

Edit:  trace the outline with a utility knife.  You can’t afford any tear-out when the bit exits the frame.

[museumguy]

I interpret it to mean take the door off to get it out of the way and then route the frame.

[chrisntam]

Thanks for all the replies, I'll just open the door, it will be out of the way a plenty. It goes on the latch side, not the hinge side.

I'll prolly just heavily score the outline and attempt a freehand router cut out.  Doesn't need to be very deep.

chris.