CR-10 Dual Z axis with single stepper. Low cost high precision.

The CR10 has a single Z axis leadscrew and I have no issue with this it really produces superb prints. From an engineering point of view a better idea would be to have a leadscrew at both ends. There is an upgrade kit available which uses a second stepper motor but I understand these can get out of sync when power is switched off and on and the bed must be re leveled every time.
My solution links the screws with a toothed belt and is driven by the existing single stepper. It cannot get out of sync.
All the parts cost less that £12.00 ( US $16.00) including delivery!
There is a bit of metalwork involved but you only need a saw. file and drill. If you really cannot do metalwork I have designed a printed bracket with the same dimensions. Be warned though this has not been tried out but it should be OK.
Parts needed include
600mm leadscrew and nut https://goo.gl/fM8znL
GT2 Aluminum timing belt pulley 36 teeth 8mm bore ( 2 required)
http://bit.ly/2DXpmch
GT2 852mm Timing Belt: https://goo.gl/iXa4sv ( be sure to get the correct length)
Flexible Shaft Coupling: https://goo.gl/qfUhEe
Bearings: https://goo.gl/HnzTqr
Video https://youtu.be/-ASBhJiU8NI
Instructions http://myfordboy.blogspot.co.uk/p/the-cr10-has-single-z-axis-leadscrew.html
Beware of ordering the leadscrew form other than the link given. There are 2 forms of 8mm leadscrew available.
One is a 4 start thread that gives a 8mm travel for one turn, the other is single start that would move the nut 2mm per turn.
The details are not given very clearly on some sites. I made the mistake and ordered the wrong one to start with.
UPDATE
Some people have said the printed bracket fits and others say the fixing holes are too close together. I have uploaded another file which has a slot so should fit OK.