screeching sound-is that normal?

I just cut my first lithoplane-roughing toolpath. I used a tapered ballnose and it cut fine but it made a high pitched screeching noise as it cut. Is that normal? My bit was not hot when it was done...hadn't cut a litho in the past so wasn't sure...haven't used tools much:-) Thanks, Robin

I have not cut a lithoplane but it does not sound normal to me.

That tapered bit is especially loud due to its length. If you are happy with the finish that it is leaving then I wouldn't worry about it. However, if you see signs that bit vibration is marring your finish, you should reduce the stepover for your roughing pass. This can be changed in the toolpath window by clicking "edit" next to your bit selection. Choosing a smaller percentage for "stepover" will reduce the amount of material the tools tries to remove with each pass and should reduce chatter.

Thanks, since this was a roughing pass I had it set to 50%. My finish will be a smaller bn at 12% so I'll see if it makes a difference. Several people have told me the 1/4 inch corion really doesn't need the roughing. Anyone feel differently? My finish will be a 1/16 bn but would like to go smaller sometime...