Being new to the CNC world, I have gotten 4-5 real projects under my belt now. Recently started wondering “How long do tool bits typically last?” and “What do you look for to know a bit is ready to retire?”
“Most” of what I have done so far has been with softwoods like cabinet grade plywood and MDF.
Any insight out there is appreciated!
Wes
I find they last quite long, provided your feeds and speeds aren’t way off. They typically last so long that I lose track of when I installed it in my ATC.
As they wear, the cut quality will diminish. The edges of the wood will look progressively rougher. Wood burrs will form, splintering will occur.
There’s normally a period when a cutter works to cut, but it is no longer suitable for projects that require a nice finish. Cutters will often get changed out when a project comes up that I want a nice crisp finish on. The cutter then gets put in a pile of cutters that still have some life left, but only when the cut quality isn’t that important.
If the cutter or wood is black and charred, it’s past its expiry. The cutter is now burning the wood. Sawdust coming off can be warmer/hotter than usual. It’s a good idea to stop using the cutter as the heat can cause a fire. I ran a CNC shop in the past, and over several years, there were 3 or 4 incidents of fires breaking out on the spoilboard. It can be super sketchy if someone’s not present to put it out immediately.
In addition to the above, if your cutters are showing light brown discoloration, try soaking them in a tool cleaner and brushing any residue off with a small brass bristle brush. Trend makes a good cleaner or you can use Simple Green. Dry the bits well.
For v-bits it’s the tips that usually break before the bit gets dull and you can see that because the point will be flattened. I usually buy several of those at a time because I don’t want to be in the middle of a project and have one break. If the tip is flattened/broken off, you won’t get the carving geometry right for either depth or sharp corners. I’ve tried a bunch of different brands and not found any real difference in how long tips last, including CNC Workshop’s “special” design which is supposed to have a pre-flattened tip to prevent breakage. Any name brand seems to last the same.
When you’re carving softer woods, it’s important to clean your bits more often, as they usually have a higher resin content. For the bits I use most often, I keep 2-3 that are sharp. When the cut quality goes down, I put that bit in the pile used for roughing passes or for cutting things where cut quality is not important (ie. hold down clamps).
Thanks a bunch @MikeXYZ @JimHatch @TommyObar , sincerely appreciate the guidance.