Hey all, need some quick advice. Cutting a .2" pocket into Walnut around these stars. Used a .0625" EM, and a .125 compression EM for clearing. Both endmills caused the stars to break apart. I’m currently cutting a flat pocket to fix this and plan to cut new stars into Walnut and going to CA glue them in. Was going to paint the bottom of the pocket and sand the tops of the stars, lacquer after to show the grain. Any ideas on how to get these to not break on me?
Instead of compression bits you could try downcut bits. I have had good luck with 1/8" downcut bits to avoid fuzzies and chipping but haven’t tried any smaller than that. For your .0625" cut you could try something like this:
Thank you. I haven’t cut the pocket flush yet so In a last ditch effort I’m going to try cutting the height of the stars down by half but cutting in raster to cut along the grain. Seems most or all of the tearout was when cutting against the grain (top of stars)
on anything with a sharp detail protruding like that, I will first set a toolpath to “outline” the detail (offset to cut the outside) down to the desired depth. You have to go super slow and shallow because you are slotting the whole time. My go to “detailers” for these paths are 1/16" and 1/32" 4 flute up cut end mills at excrutiatingly slow speeds. I add geometry around the details, offset at around half the chosen endmill size used to cut the “outline” and set my bigger/faster pocketing path to the new geometry instead of the original so the pocketing endmill never comes in contact with the detail.
edit: Also I should add, I started doing this because I was dealing with a lot more runout with small endmills than I should have been. Some Elaire collets ended up solving most of the issue and I find now on my “test” cuts that I don’t need to go back and add all these steps to prevent chipping. Picture shows 1/32" bit for scale.
I’ll offer a different perspective here. Maybe your choice of wood is not the best for your application. Walnut, in my experience is, temperamental in this respect. It splinters, chips and tears out easily. It’s just the nature of its grain. I love it but you have to be careful and sometimes all the care in the world isn’t enough. You might try applying a coat of poly or shellac before you mill and let it cure fully. That might provide enough reinforcement to the fibers to keep them from chipping and splintering.
Thank you guys for the help! I had to redo from scratch. I ended up cutting the profiles really slow with an offset as suggested then cutting the pocket offset in. Worked much better.
