LumberJocks

Makita Belt Sander Sparking in Armature?

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by DMiller posted 08-21-2017 05:08 PM 1126 views 0 times favorited 19 replies Add to Favorites Watch
View DMiller's profile

DMiller

150 posts in 225 days


08-21-2017 05:08 PM

Topic tags/keywords: question belt sander makita sander

My aging Makita 9401 belt sander began sparking abnormally around the armature. Has anyone ever had this happen or know what may be the cause of it? It seems to abnormally spark when running and i’m not sure if it is safe to still use? Is there any specific part that may need to be replaced, or would you say its seen better days? Thanks…any help is greatly appreciated! DMiller

-- Dale Miller Modesto, CA "Woodworking minus patience equals firewood."


19 replies so far

View splintergroup's profile

splintergroup

1480 posts in 974 days


#1 posted 08-21-2017 05:12 PM

Is it the motor brushes?

They could be reaching their end of life or are gummed up in their slots and sticking.

View MrUnix's profile

MrUnix

5707 posts in 1951 days


#2 posted 08-21-2017 06:05 PM

Yup, check your brushes… a replacement set is under $10

If they look in good shape, then you may need to pull things apart and clean up the commutator (also a good time to check the condition of the bearings while you have it apart).

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View DMiller's profile

DMiller

150 posts in 225 days


#3 posted 08-21-2017 07:17 PM

Thanks, both of you for the replies. Is it possible to replace/ clean the brushes myself or would I need to take it to a repair center? How difficult are they to replace/ clean? Thanks for the replies….DMiller

-- Dale Miller Modesto, CA "Woodworking minus patience equals firewood."

View MrUnix's profile

MrUnix

5707 posts in 1951 days


#4 posted 08-21-2017 07:32 PM

Thanks, both of you for the replies. Is it possible to replace/ clean the brushes myself or would I need to take it to a repair center? How difficult are they to replace/ clean? Thanks for the replies….DMiller
- DMiller

To check/replace them, all you need is a screwdriver (See page 6 of your manual under “Maintenance”).

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Ripper70's profile

Ripper70

419 posts in 661 days


#5 posted 08-21-2017 07:34 PM

It’s not too difficult to replace the brushes and for the effort would be worth it rather than cleaning them. There’s a schematic pictured here and replacement parts are about $8.00. You might find them on eBay as well and possibly pay less for shipping.

-- "You know, I'm such a great driver, it's incomprehensible that they took my license away." --Vince Ricardo

View splintergroup's profile

splintergroup

1480 posts in 974 days


#6 posted 08-21-2017 09:34 PM

Now that is service Brad 8^)

I agree with the idea of taking the unit apart if you have the basic skills and know how to catch hidden parts that like to leap from within when set “free”. It’s nice to inspect the motor, clean out the crud and give the bearings a spin and feel for smoothness.
If you can shine a light on the commutator (the copper looking part that the brushes ride against) when you have the brushes out, look for grooves and/or signs of arching/melting. If your brushes are truly down to the springs. the commutator could have rough spots that will eat up a new set of brushes. To the contrary, if the old brushes still have some carbon left and the faces look smooth, you commutator should be ok

View Jim Jakosh's profile

Jim Jakosh

19081 posts in 2857 days


#7 posted 08-21-2017 11:51 PM

It sound like the brushes are worn down. It would be nice if you can get that armature out and polish the commutator down for the new brushes to ride more smoothly, too.

I have a D handle Makita router and I had to cut off the cord a bit and move it up because the wire broke where it was bent a lot. I was truly amazed at how easy it is to work on a Makita tool compared to the likes of Harbor Freight. The wiring has lots of room and it assembles back so easily!

cheers, Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View DMiller's profile

DMiller

150 posts in 225 days


#8 posted 08-22-2017 01:15 AM

Thanks for the replies, guys! So using a flashlight iv’e checked the brushes… from what I can tell the have about 1/10 in. (3 mm) of carbon left on the brushes; how much should they have normally? Splintergroup, when you say ‘knowing how to catch hidden parts that like to leap from within when set free,’ is this meaning how to get the brushes back onto the armature? I have messed around with some comparable sized motors trying to put the brushes back on the armature after taking them apart, and have found it quite difficult… is there any easy way to do it? To be honest, i’m not sure I would say I have basic skills in repairing motors, I think I understand the concept of how they work, but for me its a totally different story when its actually apart. What do you guys think about trying to repair it myself? I really appreciate your advice and time! Thanks!

-- Dale Miller Modesto, CA "Woodworking minus patience equals firewood."

View MrUnix's profile

MrUnix

5707 posts in 1951 days


#9 posted 08-22-2017 02:13 AM

So using a flashlight iv e checked the brushes… from what I can tell the have about 1/10 in. (3 mm) of carbon left on the brushes; how much should they have normally?
- DMiller

Using a flashlight??? Pull them out and look – no flashlight needed. If you read the manual, it shows how to tell if they need to be replaced… here is the relevant bit:

1/10th of an inch sounds like they are way past time for replacement… pull them and see.

Cheers,
Brad

PS: You can see the limit line on the picture I originally posted above (from ereplacements). That should give you an idea of what is acceptable.

-- Brad in FL - In Dog I trust... everything else is questionable

View DMiller's profile

DMiller

150 posts in 225 days


#10 posted 08-22-2017 02:39 AM

Thanks for the help Brad; I would have checked the owners manual, but I bought the machine a few years ago used and it did not come with the manual. Thanks for the help- couldn’t do it without LJ’s!

-- Dale Miller Modesto, CA "Woodworking minus patience equals firewood."

View MrUnix's profile

MrUnix

5707 posts in 1951 days


#11 posted 08-22-2017 02:47 AM

Thanks for the help Brad; I would have checked the owners manual, but I bought the machine a few years ago used and it did not come with the manual.
- DMiller

Follow the link I gave you above to the manual – that is one of the first things you should have done when you got the machine!

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View DMiller's profile

DMiller

150 posts in 225 days


#12 posted 08-22-2017 04:03 AM

Thanks Brad- I checked it out! I now get what you mean about “using a flashlight???” I was thinking you had to take the whole machine apart to replace the brushes till I realized how easy it is to replace them from the side. My brushes still have 3/8 in. left of wear on the bar so as of now I probably won’t replace them. Do you happen to know what else may be causing it to spark? Thanks- I really appreciate your help! DMiller

-- Dale Miller Modesto, CA "Woodworking minus patience equals firewood."

View MrUnix's profile

MrUnix

5707 posts in 1951 days


#13 posted 08-22-2017 04:38 AM

Well, brushed motors spark… it’s the nature of the beast. If it has become excessive, it could be caused by a number of different things… dirt or grime preventing the brushes from making full contact, springs going bad and not providing enough pressure, carbon build-up on the commutator or being worn down, fault in the armature, etc… hard to tell without having it sitting in front of me. I would eliminate the brushes first… make sure the holders are clean and the brushes can move freely in them, and maybe reverse them and running it for a while to see if that helps. If not, I’d pull it apart and check the commutator, armature windings and bearings.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View MrUnix's profile

MrUnix

5707 posts in 1951 days


#14 posted 08-22-2017 04:53 AM

Wait a minute… I just noticed that in the title, you say it is “Sparking in Armature”. Where exactly is it sparking… at the commutator where the brushes ride, or in the armature windings? I think we all have been going on the assumption that it’s the former, not the latter…

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

View Richard Lee's profile

Richard Lee

39 posts in 527 days


#15 posted 08-22-2017 02:33 PM

I had a Makita Router that was sparking,changed brushes,cleaned commutator same problem.
Turns out it was a short or a problem internaly in the windings. Tossed it and got another.

showing 1 through 15 of 19 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com