THIS IS NOT A BETA, this is an ALPHA (think 'will this work' and not 'fine tuning' )
I'm sorry to say that this has one fatal flaw, it doesn't work.
The half-tooth rack is actually on the wrong side, as if the product was mirror-imaged from what was intended (the rack should be on the right, not the left)
So, please do not buy, this is a warning to other people as this WILL NOT WORK without extensive modification, which will result in tiny 'nub' teeth being the only contact surface, (you will need to dremel 30-50% of the teeth away) which won't be good for long life. The material is great from what i can tell, but this will also mean that removing the spare material will be a multi-hour job unless you have a mill.
Shame as the material was good, and it was so close. but no cigar.
I am happy to try this again if the design is mirrored, and about 1 millimetre is removed from the center-inside edge of the piston teeth (to ensure they don't mesh with the non-driving teeth, as my next fear would be that)