Weird vcarving behavior

I’m doing raised text, 60’ vbit, toolpath generated with vcarve pro. As seen in the pic, I’m getting a ridge between the first and second passes of the vbit, on all sides of the letters. Belts are good, everything right and tight. Not sure what to make of this… Any thoughts?

I’m not thrilled with rouging pass, but I had feeds and speeds too fast for oak, so minor chatter.

Is this the final, or roughing pass? I would try a shallower depth of pass. Too much chatter.

It’s the v bit portion of the cut, roughing pass already done with 1/8th bit, vbit took 3 passes and there was no chatter, it sure seemed as smooth as glass… I’m going to try to cut the whole thing again in mdf.

Good suggestion, thanks

Is that the marks from the 1/8" ball in the “a”

no ball for roughing, flat, but the inside of the A was 2 passes with vbit, no roughing of the A

It looks like maybe your z steps could be off? So the bit is not moving down enough for the second pass?
Maybe double check your z axis calibration.

60’ vbit, 25" shank, pass depth 0.1, clearance stepover .06 (24%), final stepover .01 (4%), 40ipm and 30ipm plunge

I am going to cut again in scrap MDF to see if the hardness (oak) impacted the cut enough to do that, although I watched it while carving and didn’t hear or see any chatter or anything else that looked amiss.

all 3 belts are right and tight, no missing teeth, vwheels are all snug, no play in any of the axis

I slowed things down for the vbit in the tool library once upon a time when doing ironwood, haven’t changed it back since. All the vcarving I’ve done since has been flawless, until now.