Tool Diameter Offsets or Better Method for Making Inlays

Hello All,
              I made a 10mm x 12mm square pocket and a "matching" square cutout/contour. The pocket was more like 9.6 x 11.6 and the cutout more like 10.4 x 12.4. My end mill is 0.8mm. I went through a bunch of fussing with scaling inside of fusion to get the squares just right. Then moved on to a set of donuts with island applying the same scaling. It's a nightmare. Then if i do manage to get it just right I have a bunch more to do (not really but there are other things i'd like to use this technique for). 

So over in the fusion forum a person is telling me to use the tool diameter offsets within linuxcnc. I can not find this anywhere. I've tried changing the tool diameter inside of the tool table, saved, reloaded and absolutely no change in the carve. I figured there wouldn't be but it was worth a shot. The only tool offset I can find anywhere is the length of the tool.

Thank you,
John

So lie to fusion about the diameter sounds good to me and I'm sure i can find more happiness with that than with scaling. Trouble is changing the tool diameter for a single tool several times for two operations in the same setup... Not sure how this would work. I'll head over to fusion and ask. Thanks Tommy.

Best,
John

So I guess I'm not really clear on how to tell fusion about the offsets or how to tell it to apply them. I cloned my 0.8mm tool. Changed the id from 65 to 67 in fusion. Changed diameter to (tried 0.79, 0.78, 0.75 and 0.65). Generated new tool paths and posted using grbl as usual. I also made the clone and subsequent adjustments in linuxcnc tool table, saved and reloaded every time. Not a single change. My 10mm square with an inside pocket consistently comes out 9.8mm. The only way I've been able to get to 10 is to sketch the square a bit over 10. I have stock to leave set at zero in the pocket operation.

So this seems to have turned from how to properly make an inlay to what is cutter compensation and how is it used. I can tell you right now from 10pm to 2am is not the time for me to be messing with this stuff. Today I'm having slightly better results.

I have posted a pocket operation using emc processor and using in controller compensation. Then over in linuxcnc I load the file, make a change to tool# 65, reload the table and the file and boom i can see a clear change in the path on screen.

I've been reading over the tool compensation documentation, but this stuff only confuses me until some part of it makes sense or i can see it in action. Then i start messing with other bits and making more sense.

I might just cut a perfect 10mm x 12mm pocket yet today.

Thanks again,
John

So I worked at this somewhere around 12 hours yesterday ending around 3:30am today. As it turns out much of my struggle was with a poor design in fusion. After getting that ironed out it only took a few attempts and logging results to get a killer fit. I'm still trying to understand just what's happening when using crc at the mill, but for now at least i can make it work.

This is a square pocket with an island, then a square donut. I could press them all the way together but would never get them apart. So today it's back to the mission of inlaying a mahogany heart in an oak box lid.

If you use an angled bit (like 15 degrees) for the walls of the pocket and the insert it will be more forgiving for size errors when doing inlays

I think you're correct on the G41/G42 and grbl.my ProVer 4030 did weird things until I told QCAD/CAM to use the GRBL thing.