Below is described an alternate way of mounting the sending part of a contact sensor in a door frame with a simple clean look. The magnet portion of the sensor is removed from its plastic case and forced into a 5/16” ø hole in the edge of the door opposite the sending unit’s location.
After looking at internet pictures of installed 3D printed accessories for inclosing and placement of contact sending units in round holes in doors or door frames, I noticed an annular gap between the printed accessory and the hole it is placed in. In some of the photos presented there were also visible tear-outs along the edges of the drilled hole. These less than optimal installations appear to be caused by sloppy drilling. When a spade bit initially bites into the wood it can get away from the operator causing scaring and tear outs. When a spade bit is placed into a shallow hole to deepen it, it can go wild on the operator resulting in an irregular and oversize hole. Often there is a significant void behind the door frame to the door framing studs, resulting in over depth hole for the sending unit.
Only simple everyday tools and materials are required.
The installation method is described below using a mock-up door frame:
In picture 1 below mark the spade bit with tape at 1-1/2” and try to drill all the way in, in one pass. Better to be a little over depth than shallow. The over-depth will allow for an adjustable stop or support. In picture 4 below the screw can often be shorter than shown (may only need a 1” long screw).
Pictures 5 to 8 show installing the adjustable stop/support for the sending unit.
Pictures 9 to 12 show making the hole cover plate. You may have better ways of doing this. I am constrained by the lack of half of my fingers (no thumb) on my left hand.
Pictures 13 to 16 show the finished work and ease of removal.