Wood Router, Snapping Cutters

[mitchejc]

Hi Matt, below are just two examples of the same problem you have. I even tried to go with 6mm with a 1/2" shank and that broke just as easy and trust me these on the photo were not the only two I broke:-) I even managed to break a quite expensive WP 1/4" x 1/2 shank cutter, it lasted a longer but not much. Unless I ran these 6mm straight flute cutters with air blast, at low feed and shallow depth of cut they broke long before they get remotely blunt. They break while slotting straight or curved sections and never broke during a plunge or ramp-in. If I want to break a brand new one within 10 seconds I just cut some of those dark brown HD fibre board at the feed/speed/DOC you mentioned above. Gmmf, they die so gracefully, no real nasty sounds, nothing gets flung across the workshop, the spindle just leaves half the cutter behind in the slot... :-)

Earl has a point, not all of these straight flutes can plunge straight down. I normally bought the ones that can plunge but it did not make much of a difference in the results I got, nether did changing brands.

I don't know but I think its got to do with limited chip clearance or something. I'm not saying this type of cutter is junk but I for one, had no luck with them in 6mm. The larger ones like 1/2" x 1/2" straight flute cutters never breaks and lasts till they are blunt but they also don't like aggressive cut depths while slotting, in my experience. On the larger diameter ones it takes quite a but if cutting force at more aggressive DOC. Try one in a hand router and you'll understand what I mean.

For 6mm dia go for single flute or even two flute spiral cutters and you will have MUCH more joy, faster feeds and you'll cut them till they are properly blunt without breaking and you'll save money.


I would be curious to know if other CNC'ers are using these straight flute 6mm cutters at reasonable feed/speed/DOC with success in ply or harder types of wood.