V-Groove bit question for sign makers:

[germanguitars]

I just got a 60° insert V Groove bit from Amana. I don't have a lot of experience with 2D carving or sign making, and I have some questions about feeds and speeds for a project. 
Planning to cut 3/4" baltic birch plywood at full depth in order to make some islands that will be flipped, glued, and used as dovetail edges for a kind of bracket.
I found a suggested speed of 18,000 and feed of 90 ipm on a video from Tools Today, but the maximum depth per pass is still unclear to me. 
I did a test cut in cheaper plywood here at 18,000 RPM and depths of 1/8" and 1/4" at 30 ipm, 60 ipm, and 90 ipm. The bit does not struggle at all with this, but you can see that the cut quality goes down as the speed goes up. Before I attempt any deeper test cuts, do you sign makers have rules of thumb on deep cuts like this? My intuition says that 0.25" per pass is about as aggressive as I should go. I don't want to break the insert since the chip load on that tip is high.

[gerry]

That's about as deep as I go in a single pass. You are correct in that the quality goes down the more you push the bit. You can rerun the pass @ full depth to clean up the fuzzies. Sometimes I'll put on a coat of shellac before the final cleanup pass. Then it will shave off the fuzzies. The slower the cut, the less problem with chipout on a critical vcarve or lettering.

[germanguitars]

Thanks! This will be for a structural part that just needs to mate with a corresponding dovetail. Won't even be seen, so the fuzzies don't matter that much. Nice baltic birch will cut differently than this cheapo 'Sande' plywood from Homeless Despot. Won't buy that stuff again.

[germanguitars]

Yup - 0.25" DOC at 60 ipm will be just about right. The plunge speed needs to be slower or the bit barks loud on the last plunge -  I dialed it back to 25 ipm and it seems happier.

[johnb]

Feb 28, 2020 13:35:10 GMT -5 germanguitars said:

 Homeless Despot.