Here is a picture. it’s the lines going the same directions as the arrow I drew. It kind of seems like chatter but the x move areas are smooth. what would be some stuff for me to check? would a bad bearing block do this? Thank you.
I recently did a project where minimizing these lines was key. I have two observations that might help:
Tram your spindle! If it only happens in one axis (X motion vs Y motion), it’s likely your spindle is tilted a bit in the other axis (i.e. if motions along Y cause lines, you’re tilted in X - the tilt is perpendicular to the motion). I ended up building a tramming tool for mine and found it “nodded” forward quite a bit.
Inspect the lines under a microscope. I found that climb vs conventional cutting caused a different type of tear-out in the underlying wood pores, as well as the different feet-per-minute tool speed for the different sides of the bit. You might need to change your toolpaths to be less than 50% overlap and only one direction.
The other thing I thought of trying, but didn’t, was to use a bit that had a radius at the tip instead of a sharp corner. I thought the sharp tip was scratching the underlying wood, but it turned out that the above two options fixed it well enough. I also made sure my toolpaths ran in the same direction as the grain, to help hide what lines remained.
By this I mean, most metalworking end mills have a small radius, like 0.010 inch, instead of a sharp 90 degree corner like woodworking router bits have, at the outer edge of the tip of the cutting surfaces.
I’m talking about the lines you can barely see running the same direction as the arrow line. i know what the line the arrow is pointing to is. sorry i didn’t mean to be confusing.
Figured it out. Had just a hair of play on the right side of my gantry. found a few of the bearing block screws that were under stuff loose. seems good to go now. I guess no more getting in a hurry when re tightening things. I know I should have looked there sooner. last time I looked for stuff to retighten I didn’t want to re set my square sensors so didn’t take it all apart. Lesson learned.