router bit migrated off the tool path

[270mag]

While forming a profile, the tool "bit" hard into the wood and veered off course. Any ideas what caused this? See the attachment.
- .25", 2-flute, spiral, upcut bit.
- spindle speed 18000 rpm
- feed rate 90 inches/min
- cutting depth .1" into a .75" thick board. 8 passes. Problem occurred on pass 6 or 7.

[Bob]

There are many possible causes:
The bit may have come loose.
The collet may be not clean.
The bit may be extended too far out of the collet.
The wood may not be clamped down securely.
The bit may be dull.
The collet or bit may have lubricant on it, causing the bit to slip.
There may be sawdust in the collet preventing it from being tightened properly.

How's that for some places to start?
Bob

[270mag]

Great suggestions, Bob. I think the most likely culprit is a dull bit, but those other considerations are something I'll watch out for in the future Thanks.

How does one tell when a bit is getting dull before something this radical happens?

Jon

[Bob]

Jon
You may have a dull bit when:

Burn marks are on the wood
Discolored bit
Fuzzy edges on cuts
The cut no longer looks clean
The cutting may sound different than when the bit was new
Making dust instead of chips
Magnified visual inspection of the cutting edge shows a dull bit
A bit that is running hot

There are more, but I can't think of them right now
How's that?
Bob