Angle Drill for Sanding Failure

[Thomas Canfield]

I had yet another failure of angle drill used for sanding. It made 2 Neiko brand that failed in the last 3 months, both being about 3+ years old so not that much a surprise. It seems that all the drills fail with the rear motor bearing failure or the plastic supporting the bearing overheating and bearing wearing out support. I suspect it is a bearing failure. I had a Milwaukee in the past that failed in same manner along with a couple more red and one blue cheapy. Length of service from all seems to be about same 3 years of seldom use with 2 or 3" sanding disks. Maybe the different manufacturers do not get any reports on the types of failure (all same basically) so that they can correct the design problem, or possibly it is a planned failure point to sell more drills. Have others had similar failures?

[John K Jordan]

I had yet another failure of angle drill used for sanding. It made 2 Neiko brand that failed in the last 3 months, both being about 3+ years old so not that much a surprise. It seems that all the drills fail with the rear motor bearing failure or the plastic supporting the bearing overheating and bearing wearing out support. I suspect it is a bearing failure. I had a Milwaukee in the past that failed in same manner along with a couple more red and one blue cheapy. Length of service from all seems to be about same 3 years of seldom use with 2 or 3" sanding disks. Maybe the different manufacturers do not get any reports on the types of failure (all same basically) so that they can correct the design problem, or possibly it is a planned failure point to sell more drills. Have others had similar failures?

Thomas, I've read about a lot of these failures over the years on other forums. There were some reports that dust buildup is the problem and suggested regularly blowing out the dust.

My only experience is with a Milwaukee I've had for well over a decade. I did blow the dust out occasionally but I quit power sanding at least 5-6 years ago so I can't comment on the "normal" life. (I switched to hand scrapers instead of power sanding and more recently started using the Grex random orbital sander with 2" disks - fantastic, far more gentle and easier to control, I think better results. But it is expensive and needs a big compressor.)

JKJ

[Thomas Canfield]

John,

Dust buildup inside the drills is a problem, but not seen in the area of the failure on the internal real next to brushes. Heat has to be a big contributor. I don't use the angle drill for sanding as much as earlier using a lot of hand sanding now and recently did get a pneumatic orbital sander but do not use it that often either. I use a 5"ROS a lot on external large surfaces where not as likely to have flat spots. I need to try a scraper.

[Olaf Vogel]

I had yet another failure of angle drill used for sanding.

Drills are not mean for continuous use like that. So they overheat. Its also possible that your hand is covering the exhaust vents.

1 - Get a "milwaukee right angle drill attachment" or similar
https://www.amazon.com/DEWALT-DWARAF...rds=flex+shaft
2 - Hook it up to a generic flex shaft kit like this: https://www.amazon.com/Enkay-115-C-S.../dp/B001PTSWJ6
3 - Attach any old 1750 rpm surplus motor of 1/5 hp or more.

That will be quiet and run all day without getting hot. A bit of DIY, but cheap.

I do large pieces and thats how I sand. Thats what I used, hard, for 5 years with 3" and 5" discs, I have never burnt out a motor or any of those parts.
(Last year I got lucky and found an old machine like this: http://www.terrco.com/flexshaft/flexshaftgrinders.php, so its what I use now. Same idea as a Foredom, but with 2 hp.)

[Brian Kent]

The longest lasting for me has been the Harbor Freight $39 drill (before coupons). Lasted much longer than my Neiko and was inexpensive to replace when I needed to.

[John K Jordan]

Dust buildup inside the drills is a problem, but not seen in the area of the failure on the internal real next to brushes. ...I use a 5"ROS a lot on external large surfaces where not as likely to have flat spots. I need to try a scraper.

If dust can be found elsewhere on moving parts in the motor housing, perhaps near a front bearing, it seems possible that it could cause friction and make the motor work harder, causing more heat in an area with no dust. I haven't examined a failed one so this is speculation.

Have you seen the 3" pneumatic ROS (palm sander) that Woodturners Wonders sells for pretty cheap? One nice thing about it is the valve can be set to limit the speed as desired. I usually sand pretty slowly with the lathe off - I have more control and the amount of dust in the air is less.

I've used these and a few other scrapers since soon after I started turning and discovered too much heat from sanding put checks in an eastern red cedar bowl. I cut the first one from the end of a larger scraper with a Dremel then found various sets over the years. Sharpened and burnished burr just like a cabinet scraper.

scrapers_.jpg scraper_PB054025_s.jpg

However, just last year I discovered these much thicker scrapers sold by StewMac (Stewart McDonald) who cater to people who make musical instruments. They are expensive but high quality and the edge lasts longer. I use these now where I can, or at least try them first, especially the smallest one.

http://www.stewmac.com/Luthier_Tools...e_Scraper.html

JKJ

[Don McClure]

I too have had all the angle drills fail, even the expensive ones...so I stick with the Harbor Freight $39 version and use one of their easy to find 20% off coupons. I usually take out the "protection" program. Write the date pf purchase on the drill with sharpie or engraver and hang on the receipt. So if the drill fails before a year, I walk in with it and out with a new one. Sone or their drill will go 3-4 yrs before I wear them out!
They are considered a disposable in my shop.

[Grant Wilkinson]

I think the other reason that drills fail is that we are putting big side loads on the their bearings. The drill is made for drilling. Doing that, there is almost no side loads. We put a 3" disk on them and push it into spinning wood. The side loads are much bigger than the bearings are made to take.

The solution is to buy a sander - or live with limited drill life. :-)

[ALAN HOLLAR]

The rear bearings are too small, and mounted directly into a molded seat in the drill housing. When the bearing gives up and seizes, the outer race spins in the case and melts the bearing seat, so that even replacing the bearing doesn't work. I have right angle drills from DeWalt. Actually, one of them is in the black case from the Black and Decker professional line so it must be 20 years old, and all are working fine. The rear bearing is larger and sits in a rubber cup that seats in the drill housing. I have replaced the gear box on the oldest one, but the front and rear motor bearings are still good.

[John K Jordan]

.. When the bearing gives up and seizes, the outer race spins in the case and melts the bearing seat, so that even replacing the bearing doesn't work. ..

It sounds like occasional preemptive bearing replacement would be helpful for those who use these for sanding. I haven't checked but usually bearings are are cheaper than dirt, or, at least cheaper than compost!

Could the melted seat be rebuilt with some JB Weld? (a new bearing for a mold, thin plastic wrap for release) I've repaired a bunch of plastic things around the farm with that epoxy. But it might not be worth the effort for the cheap one...

JKJ

[Joe Frank Porter]

I too had a failure with the multi-named angle drill. As advised on this site, I went with the Harbor Freight angle drill and have been pleased.

[Reed Gray]

I used to keep a loose count of bowls sanded before the drill failed. First of all, they are drills, not grinders, and we use them as grinders. I can't tell that the dust does any thing serious for wear, especially if the bearings are 'double shielded' rather than 'shielded'. I used to get 300 plus bowls per rebuild. I started sanding at low speeds, never more than half a trigger pull, and with very light pressure, which lets the abrasives cut far better than they do if you are sanding at high speeds. I almost always use 3 inch discs. The bowl count went up to 450 or so. I have replaced the cases on all of them at least once. I had one cheap knock off brand, and it didn't last a month before the case failed. Looking for some thing better, but thinking a flex shaft would be the way to go. The Fordham set up can take 3 inch discs, but don't think they would be pushing the limits with 3 inch discs, even with their larger motor, and it would be good to be able to run 5 or so inch discs... One like Olaf has would be a bit of overkill, but I don't think I could wear that one out before my birth certificate expires...

robo hippy

[Prashun Patel]

I discovered scrapers as John Jordan has. These have really been a revelation for two reasons. The first is that it is able to smooth out ridges, so my bowls are now 'flatter' than they have ever been. But they also do a great job at rough smoothing, which means I can usually jump straight to 150 or 220 grit on the angle drill. My angle drill sees less use now.

I also vaccuum my drill after each session and this has seemed to improve the life of my second Neiko.

[Bob Bouis]

One thing I would suggest is that you don't try to blow out the bearings with compressed air. Sealed bearings are...sealed, but the seal won't repel compressed air, which will end up pushing dust into the bearing, and lubricant out of it.

That's my theory anyway.

[Dennis Ford]

I have had the same failures. Usually I hear bearing noises before they seize up and destroy the plastic housing. The bearings are inexpensive if purchased online (I use VXB bearings). Changing the bearings is not difficult although reassembling the drill is tricky as you wish for three hands that fit in a small space.
I tried a right angle drill from Harbor Freight and it was much more durable but not as comfortable to use. I don't think dust is affecting the bearings that much although I agree that compressed can blow dust into the bearing which would be a problem. Excessive dust will cause overheating but I would expect that to affect the windings more than bearings.