Finished my 12" Disc Sander

[BobWarfield]

Got busy today and finished up the project. I'm very pleased with the result:

I couldn't resist loading up the disc a bit by round the sharp edges on my table brackets. It took less than a minute per bracket, freehand. I was pushing hard to see if I could bog it down, but the 3/4 HP motor never slowed a bit that I could see. I think the 3400 rpm really contribute to aggressive metal removal too.

"Before" bracket:

"After" bracket:

I think I'm going to like having this thing around a lot!

Full details of the build are on my web site (more than you wanted to know, probably!): http://www.cnccookbook.com/CCDiscSander.htm

Thanks to Dickeybird and others for providing the inspiration. Your efforts are credited in the article as well.

Cheers,

BW

 

[BobWarfield]

Postscript

One of the most interesting parts of the project was balancing the disc. It wasn't quite centered on the hub despite my best efforts at the rotab, so I had to trim the edge slightly. I was able to do that by hand with a sharp CCMT insert lathe tool:

Needless to say, this involved a great deal of caution, pulsing the motor briefly rather than going full speed, and taking very very gentle cuts. It produced the most amazing "aluminum wool" swarf I've ever seen:

For reference, that is the smallest Kant-Twist clamp, about 1" across. The tiny "fuzz" of aluminum was really cool.

After the trimming, the wheel ran perfectly balanced at 3400 rpm with no vibration. Nice!

Best,

BW

 

[cfellows]

Looks fantastic, Bob. I have a 2" x 48" belt grinder that I built, but now I'm thinking I need a disk sander as well! :-\

Chuck

 

[BobWarfield]

Chuck, do you have pix of the grinder up? I want to build a belt sander as well.

Best,

BW

 

[S_J_H]

Nice job Bob! I especially like how trued it.

Steve

 

[Bernd]

Nice Bob. Looks like I need to add that tool to the shop. ;D

Bernd

 

[Rog02]

Hi Bob:

Nice job on the disc sander. You're gonna find more and more uses for it, as time goes by. I use mine everyday for everything from deburring tubing to sanding reinforced composites.

Since I work with so many different materials, I was spending a lot of money on abrasives as the composites and aluminum tend to rapidly plug up a disc. I found a simple and inexpensive solution at Harbor Freight. ITEM 30766 is called an Abrasive Belt Cleaner, kind of like a gum eraser on steroids. A pass or two across the surface will remove the plug and restore the surface to a clean, usable disc. I keep one on each of my disc and belt grinders. Frequent use extends the life of your abrasives many times over and the payback is immediate since the cleaner costs $5.00 or less.

 

[Bernd]

Bob,

Those are self adhesive disks right? How's the "sticking" power?

I remember the disk sander attached to my dads table saw. Always had trouble with the sand paper sticking to the disk. Was fine when you first stuck it on, but sometimes a few days later would come loose a little bit on one side. (I know a circle only has one side. : You know what I mean.) Seemed like if the sand paper had a bit of a bow in it, thats were it would loosen up. Also if you got it to hot while sanding the adhesive would loosen and then it would warp.

Bernd

 

[BobWarfield]

Roger, someone else recommended I get some "belt grease" from Formax. Sounds like the same kind of stuff. I was also advised that even WD-40 would help in a pinch.

Bernd, no signs of the PSA pulling up yet, but in fairness the sander is brand new, so it's probably too early to tell. I did buy name brand discs.

FWIW, I have found this shop has good prices on abrasives:

http://www.popsknifesupplies.com/klingsporsanddisc.html

I did not buy my disks there, but I did order the belt grease from there. I intend to try them next time I need abrasives. That will probably be 2x72" belts when I get the belt grinder going.

Lots of useful machinist stuff is available from the knife making and gunsmithing communities.

Best,

BW

 

[Seanie]

Very nice indeed. Thanks for the web page too- it's great to get clear pics like that to steal ideas from

I have an old shearing grinder, with big heavy cast steel discs- I've always thought that'd make a great sander.

 

[Rog02]

Roger, someone else recommended I get some "belt grease" from Formax. Sounds like the same kind of stuff. I was also advised that even WD-40 would help in a pinch.
Best,

BW

Hi Bob:

The Belt Cleaning Stick is a soft rubber compound similar in durameter to an old fashion gum rubber eraser. It cleans the swarf out of the grit without leaving any contaminates behind.

Belt grease and WD-40 will contaminate the disc and anything you grind thereafter. The belt grease is popular when hollow grinding knives and the bladesmiths I know have belts they keep just for doing that. As far as WD-40 goes, it is not even allowed in my shop. With the wide selection of proper lubricants and penetrants available to the industry today, the only good use we have found for WD-40 is flaming wasp nests.

The idea is to clean the disc without contaminating the surface that may be passed on to a material where said contaminate would be undesirable. Consider prepping aluminum alloy for TIG welding on a disc that has been oiled down with diesel fuel (the active ingredient in WD-40). One shop I know of even keeps a seperate disc grinder just for aluminum, so as to eliminate the possibility of dissimilar metal contamination.

Bernd, no signs of the PSA pulling up yet, but in fairness the sander is brand new, so it's probably too early to tell. I did buy name brand discs.

My old 10 inch disc sander is about 50 years old now and I have no problems with disc de-bonding. The 12 inch is probably 8 years old and has never had anything but PSA discs on it, and has never had a disc fly off. Actually, in order to get the old disc off I use a heat gun to soften the adhesive before trying to pull it off the backing disc. I always wipe the backing disc down with acetone to remove any debri, adhesive residue, and oil before installing a new abrasive disc. I peel the backing away from one edge about an inch and align the abrasive disc on the backing disc, once I have the alignment correct, I then pull the backing material off as I work the disc down, making sure I work out any bubbles as I go. If needed the heat gun can be used to help reposition a disc if needed.
Back in the "Good Old Days", pre-PSA discs required a special adhesive. I can remember getting hit more than once by an errant DA disc that had been improperly glued or bonded using the wrong adhesive. I keep a can of "Disc Adhesive" around to this day for those times when I need to cut my own disc for something special ( think 600 grit wet-dry paper) :

FWIW, I have found this shop has good prices on abrasives:
http://www.popsknifesupplies.com/klingsporsanddisc.html

Good call on the Klingspor abrasives. I have been using them for years and find them economical and effective.

Lots of useful machinist stuff is available from the knife making and gunsmithing communities.

Yep! I find it useful to look around at other crafts and trades to see what they have going whenever I am considering a new piece of equipment.

 

[BobWarfield]

I'll give the sticks a try. HF has them on sale anyway, not that they were expensive to start.

I did try the WD40 and was not all that impressed. It helped slightly, but didn't make up for the mess.

The Tig crowd need to be particular. I do Tig, but don't expect things to be clean coming off the various tools around my shop. There are just too many opportunities for contamination and it is too expensive to keep special tools just for use with my Tig. I always clean the workpieces by hand before I try to weld.

Just another thought, I added a Butterfly impact wrench to my HF order--they're also on sale and darned handy. Get one and make a powered drawbar, for example.

Cheers,

BW

 

[cfellows]

I'll give the sticks a try. HF has them on sale anyway, not that they were expensive to start.

I've never tried this, but I've read that a chunk of old car or truck tire will also clean up sanding discs and belts. Plenty of that stuff can be found on roads.

Chuck

 

[Rog02]

I've never tried this, but I've read that a chunk of old car or truck tire will also clean up sanding discs and belts. Plenty of that stuff can be found on roads.

Chuck

LOL It may clean the swarf out of the grit but the smoke and smell in the shop is not pleasant.

One of my clients runs a pulling tractor in a class that allows modified tires. The shop reaks of burnt rubber from grinding the lugs down.

Probably has something to do with the lampblack and other things they add to tire rubber.