Small or large bit might not make that much of a difference in surface finish and precision but will in milling time. Depending on the accuracy of your setup, a larger bit will be just as precise if you get the feed correct. It’s the radius that might make the difference for corners. What size bits would you consider using?
I can imagine if it is a large pocket, a bigger bit will make a difference in time. I’ve been using a 3mm bit to do a 60mm pocket 15mm deep. I also have other pockets of different sizes as part of a slip fit box. I’m going to write up the whole process tonight if I can get to it.
Here is how I have it set up for the deepest operation. That is shown in red.
I"m getting a caliper reading of 69.96mm for the inside measurement. The top of the box fits inside the bottom, but it is a bit tight. I am using 3mm for the tool diameter, but perhaps that is a little small for the bit I have. I want to do some tests. That measurement might be too small for the fit I want. Still trying to figure all this out.
Interestingly enough, I had done the same operation using clamps and holding tabs for work holding and the top and bottom fit perfectly with just enough friction to hold but came apart easily. When I switched to hot glue and masking tape, the fit and tolerance got much closer, enough so that I instead of using the same line and do a part on the top and a hole on the bottom, I’m going to have to make an adjustment.
I’ve shied away from changing bit sizes because I am not sure if I’ll mess the setup and alignment. Do you have some pink foam? You can do a test in that to get a sense of what works. You can up the feed rate and not take so long and still see how the fit works. A bigger pocket and inlay will be a real test of the accuracy of your machine.
How big a pocket?
In your case, you would just select the finishing tool you want. I use a pretty small % of the tool diameter, but I just haven’t done tests to see if I could up that allowance. I’m doing cherry and walnut and the lighter pass has made a better surface finish. In the V1 documentation the range is 5-25%.
The Yellow columns in the tool setup is where you set your feed and plunge settings for the finishing pass. I think I have it set correctly. Once again, I am still learning and every part is a test.
I had a tool change routine all set up in EstlCAM and somehow it got saved over so I haven’t reworked it. Using two separate gcode files is fine and allows for a less stressful tool change. It seems to me you would want to set up a tool that is just has finishing pass settings for the second operation.