[ninewgt]

Hey guys......

I was milling wood tonight ( a plug for an rc airplane wing) with a .25 2 flute upcut bit, 13000 RPM, cuttin beautiful..... I was inside when I heard something sounding differant and the machine was going but the bit had broken....

Well I looked at my G-Code and I cannot find a problem.... Im just stumped...

Any suggestions what to look for ?

Would you run the code again or recode the part ?

The 'crash' by the way was a shallow cut 1/2" long and about .25 deeper than the rest..... it shouldnt have even broke the bit really - Im stumped....

[ger21]

What kind of wood? Feed speeds? Depth of cut? What brand bit?

[ninewgt]

I was milling plywood - about a .35" depth of cut, 13000 RPM, 2 flute bit - made by Porter Cable..... The plywood is the 3/4" 9 ply stuff at home depot - not the cheap stuff - imported 'sand ply' as theyu call it - good stuff,pretty hard...

Also - I was running at about 50 IPM, and the step over was 25% (.0625") I have to order a new collet now - it marred my collet some..... so I need to figure out what happened.....

[ninewgt]

Pictures........

[ger21]

It looks like the bit came loose in the collet. If it had just snapped it wouldn't have cut deeper. On our router at work I use these: http://www.vortextool.com/standard/p...fm?groupID=264

#1830, If you buy 5 they are $77 for 5. I usually cut around 120ipm @19,000 RPM (for the 1/4" tool), and try to keep the depth of cut to around 1/4" . The 3 flutes cut a little nicer, and they are quieter.

[ninewgt]

Well I tacked a piece of foam down (2" styro) and ran the part file - came out fine... so ??? Who knows - maybe some electrical noise, the bit just broke... who knows.......

I wish Id have been watching when it ran over the same area - but it cut perfect so no worries