Tools #2: Check your motor brushes on your power tools.

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Blog entry by CMHN posted 09-08-2013 01:59 AM 1350 reads 0 times favorited 7 comments Add to Favorites Watch
« Part 1: Look what followed me home today. Part 2 of Tools series no next part

I was out in my workshop today making some sawdust. I am trying to get some projects completed for a show I am going to next weekend. I was ripping some boards on my table saw and about 30 minutes into it I started to smell smoke. I turned the saw off and found the sawdust that was under my table saw on fire. I was able to quickly tamp it out but was wondering what caused it. I knew I didn’t hit any nail’s even though it wouldn’t have surprised me since I was cutting old pallet wood. I turned the saw on and quickly saw that my motor was sparking excessively and shooting some sparks out at times. I didn’t notice it earlier because I was using a sled. So I took the blade off and blew the sawdust from inside the saw out with compressed air. Turned the saw back on and it was still sparking. I decided that I would pull the brushes out of the motor to check them and found that they were wore out. While looking at my owners manual to try to find a part number for them I noticed that it actually states that you should check them after the first 50 hours of running and every 10 hours after that. This is something that can be forgotten and if I had a dust collection system hooked up I might have had a major problem. I didn’t have any damage, only downtime at a bad time.

-- Chris ,

7 comments so far

View Dallas's profile


3599 posts in 2540 days

#1 posted 09-08-2013 02:13 AM

Question: why would a dust collection system have made a major problem?

I try to replace brushes every so often, sometimes every year like with my Chinese built angle grinders and sometimes 2 or 3 years, like with my old Ryobi BT3100 that I dropped the motor housing on when packing it to ship….

Brushes are cheap, downtime is expensive. Maintenance might be a seemingly excessive waste of time, (After all we would rather all be building something), but in the long run a bit of oil, a shot of grease, a set of brushes keep things going for decades.

I usually have breakdowns like the one today… I broke the spring on the clutch of my chainsaw… something unforeseeable.

-- Improvise.... Adapt...... Overcome!

View Dusty56's profile


11819 posts in 3741 days

#2 posted 09-08-2013 02:48 AM

Preventive maintenance is always a good idea : ) Thanks !!

-- I'm absolutely positive that I couldn't be more uncertain!

View Bluepine38's profile


3379 posts in 3138 days

#3 posted 09-08-2013 04:33 AM

A spark getting sucked into wood dust being pulled in a nice cloud could have caused an explosion, or just
started a fire that the fan would have pulled into the cyclone or other collector. Flammable dust can make
a nasty explosion and/or fire.

-- As ever, Gus-the 79 yr young apprentice carpenter

View Dallas's profile


3599 posts in 2540 days

#4 posted 09-08-2013 10:54 AM

It seems to me a static cloud of dust all over the room you are working in would be just as explosive, possibly more so.

-- Improvise.... Adapt...... Overcome!

View CMHN's profile


17 posts in 1941 days

#5 posted 09-08-2013 12:36 PM

@ Dallas,

I just thought as Bluepine38 that if a spark got sucked into the vacuum hose that it would cause a fire in the catch bin and with the continued air would turn into a blast furnace quick. I bought this saw used years ago and never got an owners manual with it and it never dawned on me to check the brushes for wear. Now I know and it will be part of my routine maintenance for the saw.

-- Chris ,

View Dallas's profile


3599 posts in 2540 days

#6 posted 09-08-2013 06:29 PM

+10 CMHN!

One of the reasons they recommend dust collection is that it confines flammable injuries. Maybe enough time to escape before something really bad happens, like destruction, death and general mayhem.

-- Improvise.... Adapt...... Overcome!

View NormG's profile


6202 posts in 3056 days

#7 posted 09-10-2013 12:42 AM

Wow, one just never knows, the unforeseen chances of things happening

-- Norman - I never never make a mistake, I just change the design.

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