Author Topic: Small fire in Dust Collection System  (Read 4034 times)

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Offline TealaG

  • Posts: 115
Small fire in Dust Collection System
« on: July 03, 2017, 06:53 PM »
HI...I had a small fire in my dust collection system and am hoping for help in diagnosing what might have happened so that I don't mess up again.

Here's what I know (not sure which facts are relevant):
I was trying to make the oval holes on the stretchers of a "Ron Paulk" workbench.   I had a very difficult time cutting those ovals evenly.   I cut the circles out first with a router, then I used the router and a straight edge to cut the horizontal straight parts.   The join between the straight cuts and the circles left some "bumps" and frankly, I struggled with the straight edge and my "straight edges" are sometimes wiggly.   So we have some "bumps" instead of a nice line.

I put an old, Ryobi brand 1/4" roundover bit (with bearing) in my Bosch 1617 router and figured that the roundover would "improve" the appearance of the non-straight lines.   I have a dust collection device on my router base and have the hose on it with my DustRight from Rockler)  I am not sure what happened, but the router bit got briefly "stuck" in two "grooves" (bumps?) and it looked black in the recesses.  I started smelling the burn and figured that these two black areas were rather black.   I've burned the wood before with a router and it's never been that big of a deal.   I move on.

Maybe 5 mins later I'm thinking "Boy, the smell is still strong for two black areas."...but I still keep working.    I stopped to clean up more dust that was on the floor instead of the dust collector.   Sometimes, my dust collector doesn't work well, and when that happens I unplug the fitting from the "pipeline" and it gets some air and starts sucking better afterwards.

I open up and find a pile of burning sawdust in the fitting!   Of course, I panic, turn off the dust collector, remind myself that this is small and grab my glove and put it out.   I then wet the embers to be sure.

Things were going fine until I started rounding over.   I had tried a pattern bit to try to reference off of some straighter areas (the cut isn't even and the top half was "ok" but when I plunged further, bad things happened).    The pattern bit seemed to give off a few sparks.      Timing wise though, if that had caused the problem, I would have expected to smell it much earlier (there had been at least 1-2 hrs between the pattern bit sparks and the smell...I had to take several breaks, it's 95degrees in my garage).

Note that I did check the "trash can" to see if there was a fire in the dust area, which there isn't and I checked the Dust Right bag and there wasn't any fire.   It seemed to only be in the dust collection fitting. 

Any ideas are greatly appreciated.   Meanwhile...I'm getting a new bit.   Every time I use those Ryobi bits, I either get breakage or some other calamity.

Offline six-point socket II

  • Posts: 1608
  • formerly @the_black_tie_diyer - 22/02/21 inactive.
Re: Small fire in Dust Collection System
« Reply #1 on: July 03, 2017, 07:54 PM »

When you say old router bit, you mean as in used, worn out and not sharp enough anymore?

I think it's quite obvious that when the router bit got stuck and continued to run, friction created a lot of heat and embers were sucked through your piping and set a small amount of accumulated saw dust "on fire" in that area.

Of course if the router bit itself (bushing) got stuck, that can create sparks, too.

I would refrain from using cheap or overly worn out router bits and make sure bushings aren't stuck. And most importantly when you find it smells burned, check everything immediately - you got really lucky here.

Kind regards,
Kind regards,

"... . Say yes to stuff, and it will take you interesting places." - Anne Richards, CEO Fidelity International

Offline TealaG

  • Posts: 115
Re: Small fire in Dust Collection System
« Reply #2 on: July 03, 2017, 09:01 PM »
Thanks...that's a good possibility.   "Old"  = 10 years old.   Though wear wise, I probably only used it on 6 projects?   It's not well used, but considering the quality, it may have been "worn out".    That bit set never worked well and it was cheap.   It's now in the trash and I'll start collecting new, higher quality bits as I need them.

Offline aloysius

  • Posts: 464
Re: Small fire in Dust Collection System
« Reply #3 on: July 04, 2017, 12:10 AM »
A few strokes with a fine wetted credit card sized or diafold diamond stone after each use will keep even the cheapest router bits' cutting edges as keen as mustard, and extend its useful life almost indefinitely.
FOG-wit since '95:  Some say since birth...