Linear Rails, Rack and Pinion drive NEED HELP!

[diyengineer]

[nomedia="http://www.youtube.com/watch?v=X9byjJp7zik"]YouTube- Cnc Rebuild Video #23.5[/nomedia]

Both rails have ground linear rail beds and a straight edge to align the rails parallel to each other. The 2 piece table is very level, used a .0005" machinist level. There is one driving gear linked to my servo via pulleys, that drives the gear which in turn is fitted into a long drive tube that runs under my gantry into another gear. Now the assembly has equal driving motion, from a single side. My question is how do i align the teeth on both sides being over 7ft apart from eachother? If they are not equally matched the teeth could get damaged, or instead of driving equally it might crap walk down the rails (one side ahead of the other).

am i over complicating this? Hopefully someone with a lot of linear rail/rack and pinion gear knowledge can set me straight.

Picture 1 is of the gears that ride on the rails. (before cleaning and new bearings)

picture 2 is old, before i did anything to it, but you can see how the gantry sits on the table and rides on the rails.

Pictures 3 is just a closeup of one of the rails.

I will take any pictures,videos,dimensions needed if it can possibly help me out! You can reply here or to my main build thread/log here:
15' long 8' wide Ex-Boeing CNC *REBUILD*

Thank you very Much!!

[spoiledbrat]

Perhaps somewhere along the drivetrain there is a link that can be adjusted. Are the two driving pinions on the same shaft, extending through the gantry, or is there a shaft coupler somewhere in the mix? Crap walking sounds like a bad idea.

There are ways of using marking compound to determine just how the pinion is utilizing the rack. If you search some rack manufacturers, you should be able to find it. The marking compound would wear off unevenly.

Wish I could look at that thing up close, there has to be some kind of adjustment built in, or perfection in the mounting of the racks.

Cheers!

Rob

[diyengineer]

I get the shafts with the new bearings back in 2 days. I will put the assembly together and take video with my higher definition camera in 720p. (other video was from my cell phone).

Hopefully then you can really see whats going on haha!
Stay tuned!

[diyengineer]

Perhaps somewhere along the drivetrain there is a link that can be adjusted. Are the two driving pinions on the same shaft, extending through the gantry, or is there a shaft coupler somewhere in the mix? Crap walking sounds like a bad idea.

There are ways of using marking compound to determine just how the pinion is utilizing the rack. If you search some rack manufacturers, you should be able to find it. The marking compound would wear off unevenly.

Wish I could look at that thing up close, there has to be some kind of adjustment built in, or perfection in the mounting of the racks.

Cheers!

Rob

The 2 driving pinions are connected together through one hollow steel shaft. Large steel couplers lock the steel shaft to the pinion gears. then the entire assembly turns as one.

A new HD video should clean a lot of the issues up!

[spoiledbrat]

Here is a link to some rack assembly instructions. http://www.atlantadrives.com/pdf/MPZ001e.pdf

See page 19 for the procedure I mentioned.

As long as your shaft couplers do not have a keyway, you should be able to adjust one of the pinion shafts there. More pics would definitely help.

Regards,

Rob

[diyengineer]

Here is a link to some rack assembly instructions. http://www.atlantadrives.com/pdf/MPZ001e.pdf

See page 19 for the procedure I mentioned.

As long as your shaft couplers do not have a keyway, you should be able to adjust one of the pinion shafts there. More pics would definitely help.

Regards,

Rob

thanks Rob! I will get more pics and better videos up asap!