why don't my scotchbrite wheels last?

I spent some time last night deburring the lightening holes in all my wing ribs. I used a small (2"?) scotchbrite wheel in an air powered die grinder.

It seems like these little wheels don't last - they get deeply grooved very quickly. My 6" wheel in the bench grinder also gets grooved, but not near as fast. Is this just the way it is for these little wheels?

Also, my el-cheapo HF die grinder uses a lot of air - it made the 26 gal 135 psi compressor run pretty much continuously. Would a better quality die grinder be a good investment? I haven't used it much up to this point.

Thanks, and Happy New Year to all,

dave

They don't last long at all, but sure are handy, and do an excellent job. Seems like I went through a hundred!

These can be bought cheaply at Harbor Freight. I used the "blue" wheels more than the coarser "maroon" version.

I've also found some at Sears, can be ordered over the internet, and have even cut down 3" wheels.

The six inch wheel lasted through the complete project.

edit: yes the wheels are 2", and that compressor tank will often need replenishing. You either need to add tanks, get a 60 gallon floor model, or just wait for more air, which is what I I had to do for several years until getting a 60 gal.

L.Adamson -

When you say 'maroon' and 'blue' are you talking about the Roloc-type wheels? ...Or the miniature (1-3") versions of the common 3/4-1" thick scotchbrite wheel?

Dave -

I think all die grinders suck air pretty good. The HF is likely no worse than any other as long as it doesn't leak air when not running. I had to return one because it leaked like a sieve.

mdredmond said:

L.Adamson -

When you say 'maroon' and 'blue' are you talking about the Roloc-type wheels? ...Or the miniature (1-3") versions of the common 3/4-1" thick scotchbrite wheel?

Click to expand...

They're the type that takes a partial turn twist into a plastic base mandrel. The scotchbright pad is about 3/16" thick. The mandrel also accepts the thin sandpaper disk's.

None of my disc's have the Rolac name on them, but could be of the type?

Roloc

L.Adamson said:

They're the type that takes a partial turn twist into a plastic base mandrel. The scotchbright pad is about 3/16" thick. The mandrel also accepts the thin sandpaper disk's.

None of my disc's have the Rolac name on them, but could be of the type?

Click to expand...

Sounds like you are describing the Roloc disks...

But a picture is still worth a 1000 words....



gil in Tucson

slow down

slow down the grinderspeed.you'll be amazed. i always start out turning it sideways a bit. the wheel will end up looking like a butterfly yo yo . and spread the load on the bias instead of inline with the rotation of the wheel. I will only use about 5 (2") wheels.im almost doneso i figure these will make it.. my large one is down to about 5 inches and all my edges are like the back side of a butter knife. i always
1 file off the shear notches
2 deburr with the blade or carbide bit or sand paper
3 then hit it with the wheel.
if you only use the wheel its gonna eat them.

i use the opportunity to deburr large peices as a way to dress the wheel.
cheap grinders do consume more air than say snap on or mac but your typical store variety are fairly the same. the reeeeealy cheap ones will kill your compressor.

HF vs Ingersoll-Rand

I have a HF in-line grinder and later I bought the Ingersoll-Rand right angle grinder. Not only does the IR use air much more efficiently, but I find the right angle much more useful. It is especially useful when cutting the canopy or trimming fiberglass pieces.

If you are getting grooves in your scotch brite wheel, then you are probably holding the rib edge in line with the wheel as it is spinning. So, it will cut in like a knife. Deburr each side of the edge by holding the piece perpendicular to the rotation of the wheel and move the piece side ways to get the entire length of the part. You'll have to do this to each side of the piece, but the wheel will last a LOT longer. I have built two planes with mine and it is good to go for number three. (It is a 6" wheel on a grinder, but the advice applies to smaller wheels, as well.)

Hi Dave, Luke can go through a scotch brite wheel about 4 times faster than I do. We figured out he was putting more pressure on it. By doing so he was getting the job done a little faster, but reducing pressure didn't take that much longer and the wheel last a lot longer.

BTW, I'll try to get the wing stands to you this week. Sounds like you'll be needing them before long.

Thanks to all - my little wheels (they are actually 1", from Cleveland) thread onto a fairly long screw mandrel. I also have a 2" wheel, and I've noticed that it seems to last longer, I think due to the higher edge speed of the larger radius. I think with the higher edge speed I can press more lightly and the wheel last longer.

I was able to (finallly) finish all the edge deburring on the wing main + nose + tank ribs on pretty much 1.5 little wheels, so maybe that isn't so bad. I'll just buy more!! I did go slow to spare my compressor though.... it was getting pretty hot. I changed it's oil with some synthetic compressor oil from Lowes and it seems a lot happier....

Now, on to fluting...... JohnR - the stands would be great! I'll be ready to use them soon!

Thanks again to the VAF forum members (and of course to Doug) - the technical info makes the donation a bargain!