DIY Jig For Re-installing Canon "Floating " Sensors

[michael8554]

Here's my jig for correctly re-installing "Floating" Sensors on recent Canon DSLR's.

The jig measures the height of the Torx screws with respect to the camera chassis before and after Astro Mods, so that the factory-set back-focus and sensor-tilt are preserved.

 

 

Background:
Recent Canon sensors (600D onwards I believe) no longer have the sensors installed with various thickness shims.
Instead the sensor is spring loaded and located by three Torx screws, which are T 7 size. 
The backfocus and tilt are set by how far in the Torx screws are screwed against the springs.
This makes modding a camera a much more difficult operation.

If you make adjacent Sharpie marks on each Torx screw head and the chassis before removal, the actual height of the Torx screw on re-installation only has to be accurate to one turn of each screw.
The screw pitch is 0.5mm, so the measurement with a one-turn error will be far removed from your target measurement of the height.

The Jig comprises (see image):
1) A piece of Contiboard, which has a flat hard surface.

2) A wood spacer to raise the camera enough to stop the front of the flash unit fouling the Contiboard

3) A Canon Body cap and the spacer are attached to the Contiboard with two woodscrews 

4) A "Precision Digital Height Depth Gauge Caliper Vernier", firmly attached to a steel setsquare

 

Procedure:
A)  Make a thin Sharpie mark on each screwhead and the adjacent chassis
B   Set the pointer of the Vernier onto the top of the black plastic locating post and zero the reading (see image)
C)  Now measure to the top of the Torx screw, which will be a negative reading.
D)  Do this several times on each screw and note the average measurement.
E)  After the Astro mod, re-install the screws so that the top of each black plastic locating pin is showing.
F)  Make sure the Sharpie marks are adjacent and then measure the screw height.
G) Screw in or out whole turns until you get approximately your noted readings. As I said, a whole turn out will be obvious.

Michael