Snapping CNC bits

just got CNC module, tried to make the phone holder. useing 1.5 mill end bit at 300 mm/minsnapped a bit i think because it tried to move to fast through the material, tried to slow it down to 100mm/min it still lokked to be moving to fast and snapped the second bit after the first cut was done. what have i done wrong?

What is your stepdown? Which material? In the end, it is most likely trying to go too deep too fast, or too fast in general. Start from the low end and work your way up - see when the machine starts to struggle, and tune down a bit again.

The 1.5 mm bits are fairly fragile and do snap easily. I snapped one running a boundary check where I forgot to lift it up and it caught a high spot. Unless you really need the detail, you probably should use the 3.175 mm bit.

While they do snap easily, it’s not a problem with the bits, it’s user error. Running too deep or too fast. I’ve run as small as .5mm with no problems.


I’ve been using the 1.5mm bit solid for the past 3 days without any issues (using the default settings) on hardwood and acrylic. It was just user error when I grazed the bit with my vacuum nozzle and broke it. :cry:

i was using the black plastic material that came with the snapmaker and was trying to bild the phone holder as a test. it was already set to 1.5mm bit and 300mm/min i reset it to 100mm/min it was trying to do the full cut in one go. can some one tell me what settings and bit i should have used. once i have the hang of the CNC i have a lot of engraved lettering to do.