Black dust on waste board


I was working on an additional MDF waste board yesterday and on the first attempt, the machine moved quickly at about 70 ipm when drilling the first hole, it made a big scream and had to pause and quit the job, when checking the hole I noticed a little bit of black dust and I was wondering where it comes from.

After this try, had to slower the feedrate to 30 and the depth for pass to .100 was .250 and resumed the job and it worked just fine, but I would like to know if I should check for parts condition?

Thanks in advance!

Most likely that’s carbon dust from the brushes in your trim router — which now that I think on it, makes for a good argument for directing the airflow from the trim router cooling into the dust shoe and collecting it with the vacuum (which ideally will have HEPA filtration).

Thanks for the reply,

So is this a normal behavior? I was thinking I made a mistake and something got damaged.

Good point on the dust shoe, hope I can get one in the future.

Lots of options on that, as well as designs: and

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Well, a big screech is usually a bad sighn, is it running ok now? This could be, as Will says, just some carbon from the brushes, it could also be burned MDF, it could be old crud that was already jammed in the endmill… Did the carriage run into anything like a power cord draped across the rails and get stuck?

I ran the machine yesterday for about 2 hours and worked OK.

The endmill was brand new and no cords across the rails that I can tell, so carbon dust sounds like the most likely reason, I will be keeping an eye on the router, it is fairly new, no more than 30 hours of use.

Thanks for the reply @mikep

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