Using a Bench top disc sander

   / Using a Bench top disc sander #1  

Furu

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Does anyone have experience on the use of a bench top disc sander such as
http://www.homedepot.com/h_d1/N-5yc...eyword=disc+sander&storeId=10051#.UMAh-Xf4KSo
or the
http://www.homedepot.com/h_d1/N-5yc...eyword=disc+sander&storeId=10051#.UMAhtnf4KSo
for grinding steel edges/blades. I actually was not looking at this unit but it was the one I found easy reference on line to give a link for what I was talking about.

I thought about the HF disc sander but discarded that idea.
I have been trying to come up with a good solution for sharpening my chipper's chip blades and bed knife without overheating or hollow grinding the blade while keeping a rather accurate angle on the edge. The blades are 1/2" steel (yes it is a big chipper) and would like to have a stable platform to do the grind with minimal challenges. The chipper has 9 chip blades (3 sets of 3) and one large bed knife on it and the experts who claim they know what they are doing keep screwing them up and damaging the blades which are very expensive to replace. Do the abrasive discs work well and last or are they too much trouble. This above unit and one other has a variable spin speed which should help keep the temp down which can be deadly to the steel edge.
 
   / Using a Bench top disc sander #2  
I built a KMG clone 2" x 72" belt grinder last winter. It does a great job at rapid removal of material without over heating the part. The problem with disk grinders is they have different surface speeds and can cause more stock to be removed on the outer edge vs the center of the disk. The belt grinder does a better job at sharpening various cutting edges than either the disk or bench grinders.
 

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   / Using a Bench top disc sander #3  
Hi,

I own a Delta 12 inch Disc Sander(1974 Model) and a Northern Tool 12 inch Disc Sander. The Delta 12inch is $494 plus shipping. The Northern Tool Disc Sander at 159.95 with free shipping is pretty hard to beat. In my opinion, the one you are looking to purchase looks cheap.

However, I do agree with the previous poster that a Belt Grinder/Sander is a better option for all the reasons he stated. One other option you might look at is I would consider a small combination 4 inch x 36 inch Belt/ 6 inch Disc Sander. Again for $120.00 with free shipping from Northern Tool, it is pretty hard to beat.

Hope this helps,
Benjamin J. "Joe" Browning
 
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   / Using a Bench top disc sander #4  
I agree with the others Steve, a belt sander would be a much better choice for grinding/sharpening.
 
   / Using a Bench top disc sander #5  
actually -- the reason its the blades are overheating are two things - many benchtop tools runs at 3200 rpms or faster and no water. If you look into a unit that runs at 1720 rpms or slower with water for lube, it will not overheat as much like you see now.This will allow you to actually SEE whats happening when grinding.
 
   / Using a Bench top disc sander
  • Thread Starter
#6  
I agree with the others Steve, a belt sander would be a much better choice for grinding/sharpening.

Thanks

The belt sanders that I have found are either free standing without a table or the table is not robust enough for the weight of the bed knife (30+ lbs). I will keep looking for a bench top belt sander with a good table.

Thanks guys
 
   / Using a Bench top disc sander #7  
It's been many years since I've done this, but at one time I used my radial arm saw with a chuck and cup wheel to sharpen some wide chisels. I made a jig to hold the chisels and used the elevation control on the saw to raise and lower the cup wheel. I slid the wheel across the tool by moving the carriage back and forth.

Maybe you could find a cheap radial arm saw someplace?

Just something to think about.
 
   / Using a Bench top disc sander
  • Thread Starter
#8  
Yes I still have a 25 year old radial arm saw. Using the cup wheel will do the same thing the 6" wet grinding wheel will do and that is hollow grind when dealing with a 1/2" blade. I think the belt is my best choice with the appropriate abrasive belt.
 
   / Using a Bench top disc sander #9  
I built a KMG clone 2" x 72" belt grinder last winter. It does a great job at rapid removal of material without over heating the part. The problem with disk grinders is they have different surface speeds and can cause more stock to be removed on the outer edge vs the center of the disk. The belt grinder does a better job at sharpening various cutting edges than either the disk or bench grinders.

Sfrankland, did you have a plan for your grinder or did you just build it from seeing other grinders?

About how much do you have in it?

PS - It looks great.
 
   / Using a Bench top disc sander #10  
Plans for the grinder can be found here.

http://www.metalwebnews.com/manuals/knife-grinder.pdf

I used the plans but made some changes like the tool rest is independent of the arm that holds the platen, added a gas strut instead of the spring and other small changes. I am running a 2Hp motor wired 220 Volt. The steel is all new, the motor and wiring I had and the wheels I had made by a machinist friend. All said I have about $300 into it.

Here is a video of the build and it's first use. Not very detailed but you get the idea.

http://youtu.be/HfkvWTZ8nmg
 
 
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