Well since you guys were being no fun and I got stuck doing website stuff…I didn’t ask about this update. Legs are fine I will link some good supports from thingiverse for the people going tall with their builds.
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My reasoning, please don’t hold back if I am wrong. I was very against this update since the inception of this cnc…
-Now that we know the high rpms required to turn the 5/16" rod at normal operation speeds was causing low stepper torque, this should increase Z axis power. I can testify that it does. Contrary to what I have written in the FAQ’s about this, there is much less mechanical advantage but lower stepper RPM’s and lower friction easily make up for this. I learned this on the LowRider CNC as the 5/16" would not work.
-That brass nut is going to wear quickly. So I positioned it in a place that is extremely easy to replace. 1 consumable that is very inexpensive and easy to replace, I’m sure most would agree this is worth it.
-I don’t feel the anti backlash T8 nuts or the split nuts are much better so I did not feel it was worth re-designing the whole center assembly to fit them. I might be able to modify the spacer/nut lock piece to fit them if it becomes an issue with anyone. These start with less backlash than the coupling nuts, but I am sure this will change in a short amount of use…to be determined.
-No more printed couplers. Cheaper printed parts kit, less parts required. Still able to use the 5/16" if you want. By placing the T8 touching the stepper shaft you have no positive z axis movement, and the lower bearing mount up against the coupler no negative z movement, but still get some flex if needed. The down side is the z movements will be much more coarse when the stepper is energized so 3D printing the first layer will be more difficult without an endstop.
-Had to add 2-4 longer M3 screws, but a few less 6/32" screws and nuts.
-Faster Z moves possible, making 3D cuts much much faster to do.
-I do not think I will need to change the kit price (maybe)…higher material cost but much lower labor cost. I had to chuck up and test every single 5/16" rod for straightness and coupler fit (tons of bad ones), lube them (not cheap took forever), then bag them. Pretty sure I will not miss these rods. At a previous job we swapped out I think 2000 printers worth of 5/16 rods and couplers, and hand tested another 1000 in China. I have done my fair share of dealing with them.
-No change in Z axis travel distance.
Questions, comments, concerns?
