I am very happy to report that I finally had time to test the changes and the Meticulous Z-axis is working meticulously!
I ended up re-cutting the spindle clamps and backing plane in 7 ply AB birch. The spindle clamps split when tightening so I manually cut them again using well seasoned Oak on band saw. I also changed the backing plane to be a rectangle - removing the notch cuts at the bottom on both sides and moved the bottom rail mounting posts to about 1" above the sled. I doubt I will cut any stock thicker than 3/4" so I thought that having the posts so close to the cutting range should reduce flex. This also adds a modicum of safety as the router collet cannot touch the wood stock, which could possibly start a fire, as the rails will bottom out first. I also moved the top rail clamps down about 1" to reduce flex on the rails at the expense of z-axis travel. I have 1" travel down from z-axis zero and about 1.75" up.
The difference is astonishing:
- No more terrifying noises - actually sounds like its cutting smoother than it ever did.
- No visible twisting/flexing action - Still some vibration in the rails but it does not seem to affect the quality of cut.
- Very good consistency during multi depth passes - Got a small, <1/32", lip on the 4th pass that had tabs but first three were absolutely perfect.
- Depth on pocket cuts is almost perfect - imperfection probably caused by cheap CD test stock.
- Overall the cuts are are the best quality that I have managed on the Maslow.
^ Using 2 flute up cut bit provided with Maslow kit. Only light sanding to remove squirrel tails, for better visibility, none of the plane surfaces have been sanded!
Thanks for all the support! Your input was very valuable in helping me fix the problems and getting great quality of cut.
Just to clarify - The original flexing occurred on the z-axis of the router bit and not the lead screw. The backing plane was twisting, the metal rails were bending, and I think the spindle clamps were not holding well.
Will be back at it again tomorrow running full calibration and hopefully cutting a full project. Tried my first Perspex/Plexiglass test piece and was very happy with the result. Seeing so many possibilities opening up!