Here is a guide I made to determine wood screw gauges that also lists the pilot hole size recommendations for softwood and hardwood. The holes are the actual diameter of the shank or widest part of the thread, and the fractional values listed are to the nearest 64th of an inch. There are two cases where the nearest fractional values are the same, but the hole size is actually different (#3 and #4 are both listed as 7/64", but in reality, #3 is 0.099" and #4 is 0.112"; and #9 and #10 are both listed as 3/16", but in reality, #9 is 0.177" and #10 is 0.190").
I used Inkscape and tried it with two different generic acrylics. In both cases, the holes measure correctly. In my experience, kerf is more of an issue with the solid pieces (the cut out disks) than with the holes themselves. If I want a 1/4" disk, I have to kerf correct when designing with Inkscape, but if I want a 1/4" hole, I do not need to correct.
That may be due to your Inkscape settings. As I recall, it lets you put your lines down the middle of the kerf, or on one side or the other. If it’s down the middle, which is usually the default, both the hole and the cutout are affected by kerf.
That is good to know. I just set the line width to be 1 mm so I can see it on the screen. Whenever I have made holes, the hole is what I set it to be, but if I want the solid piece to be a specific size, then I need to make the circle larger to account for the kerf.
When Inkscape is set to give you the geometric bounding box of any shape, shape sizes won’t vary with stroke width. This is NOT the default, but it’s the first thing I fix in any new installation.
When kerf correcting I find the “stroke to path” method the most reliable, and correction is needed on inner and outer edges alike for high precision results.
