I got this idea after watching a video for the Razor Sharp Edgemaking system and wanted to try it. Their system uses paper wheels. I reckoned, why not something like MDF?
The hardest part for me would be making a wheel without a lathe. I opted for the tried and true table saw with a sled.
I started with a chunk of 3/4" medium density fiberboard (MDF). Anything about 10" square will work. I cut this piece down a little as I was planning on making an 8" wheel.
Drill a hole roughly in the centre to accommodate a wood screw. The screw should fit loosely in the hole
Screw the board down to the sled so the blade will 4" from the screw. A 4" radius will make my 8" wheel. Brilliant!
Slide the sled back and forth while rotating the board.
Soon a coarse circle appears is formed.
Then with the sled stationary, rotate the wheel until the blade doesn't take any more wood off. We have a fairly true circle now.
Drill out the centre hole to match the shaft on my bargain puny garage sale grinder.
Voila! Give it a test run. If it's not 100% smooth (and mine wasn't) use a a block of wood and 60 grit sand paper. Hold the block of wood against the bench to act like a tool rest. The sandpaper should only touch the high spots and leave the low spots. This took about 5 minutes of truing.
Turn the motor off. Now work some white polishing compound around the wheel. The professional system uses a special lubricant to reduce heat.
You can apply some more compound as you use it.
WARNING!
It is very important to note that the wheel must always move OFF OF THE BLADE. Do not risk catching the blade in the wheel.
It's recommended that you sharpen on the top of the wheel with the surface moving away from you. Keep the blade horizontal and position the blade "down" the circle to get the right angle. See the image I made for this for a better understanding.
This is the correct approach for honing. I pass from ricasso towards the tip. One side, then flip and do the other. Check for any reflection off the cutting edge. When the reflection is gone. Give it a test.
Sharp like brand new Olfa blade!
My abused chisel went from dull to shaving sharp in seconds. I can't wait to try it on some knives.
Of course this is only for the finest honing. If you've got nicks to deal with, you'll have to get it to a near wire edge first.
Second hand grinder (garage sale) $10
MDF $1
Polishing compound $0.10
Experiment Grand Total: $11.10.
UPDATE
If a razor is for shaving, then this puppy is sharp like a razor.
This is really hard to photograph, but what you are seeing is the reflection of the secondary bevel. The words "ZOOM LENS" can be seen in reverse. The edge is has been mirror polished by the compound.
CONCLUSIONS:
Super fast and inexpensive. A cared for blade can be touched up in only a few passes. Amazing bargain.
I can see no reason why one couldn't use a laminate. Make sure the glue is evenly covering the pieces and clamp them until dry. This will joint will be stronger than the MDF itself.
The advantage to using leather would be that it could hold more polishing compound. The disadvantage is that the leather must absolutely stay on the wheel.
Hi awesome video and super helpful! Thanks! I was wondering, my wheel got caked with a black layer. I assume it's the metal from the knife. Do I need to clean that off? If so, how do you do it? I use a dedicated chisel but it doesn't take it off all the the way. thanks
Yes, the wheel gets caked with polishing compound. I've always added some more and carried on. To clean this from the knife edge some acetone or mineral spirits work well.
Ok, yeah I just used acetone and it helped a lot. Just need practice with the sharpening, I'm getting them sharp but want them sharper. Thanks for you quick response Dan! You have a good one.
Hello, i'm from argentina, and i can't manage to get polishing compund right here, except this one: https://articulo.mercadolibre.com.ar/MLA-626511496-pasta-para-pulir-3m-compuesto-pulidor-_JM
Just to let you know, i got it as "pasta de pulir", "polishing paste" in Argentina, maybe is useful for someone else :) https://articulo.mercadolibre.com.ar/MLA-699143506-kit-pulir-pano-suelto-7p-pasta-brillo-blanca-_JM#redirectedFromParent
It entirely depends on what wires are available motor terminals. Some motors bring out the capacitor and start winding wires, while others only the capacitor wires and one start winding wires (cost savings for the manufacturer). It's not simply a matter of swapping the power leads. A capacitor is generally used to determine the rotation and the changing the incoming power has no effect.
There is another consideration. The arbor nuts are threaded so that they maintain tightness when the motor spins in the intended direction. Running the motor in reverse would encourage them to loosen off.
You can apply some more compound as you use it.
Of course this is only for the finest honing. If you've got nicks to deal with, you'll have to get it to a near wire edge first.
If a razor is for shaving, then this puppy is sharp like a razor. 
This is really hard to photograph, but what you are seeing is the reflection of the secondary bevel. The words "ZOOM LENS" can be seen in reverse. The edge is has been mirror polished by the compound.
20 comments:
Seriously easy and useful tool! Thanks for the heads up on an easy way to make sharpening less work.
What is the polishing compound that you purchased can you put up a link to it please?
White Polishing Compound Amazon.com
Hi
Can we glue thinner sheets of MDF together for this?
I can see no reason why one couldn't use a laminate. Make sure the glue is evenly covering the pieces and clamp them until dry. This will joint will be stronger than the MDF itself.
Dan
would there be any advantage to covering the circumference with leather??
The advantage to using leather would be that it could hold more polishing compound. The disadvantage is that the leather must absolutely stay on the wheel.
Hi awesome video and super helpful! Thanks! I was wondering, my wheel got caked with a black layer. I assume it's the metal from the knife. Do I need to clean that off? If so, how do you do it? I use a dedicated chisel but it doesn't take it off all the the way. thanks
Yes, the wheel gets caked with polishing compound. I've always added some more and carried on. To clean this from the knife edge some acetone or mineral spirits work well.
Dan
Ok, yeah I just used acetone and it helped a lot. Just need practice with the sharpening, I'm getting them sharp but want them sharper. Thanks for you quick response Dan! You have a good one.
Hello, i'm from argentina, and i can't manage to get polishing compund right here, except this one:
https://articulo.mercadolibre.com.ar/MLA-626511496-pasta-para-pulir-3m-compuesto-pulidor-_JM
Do you know if this works?
Yes this should work. Also, ask a jeweler if the sell "jeweler's rouge". It is a reddish brown abrasive wax compound.
Dan
Thank you a lot Dan! I will see if i get that here in argentina, otherwise i'll try the one i showed you :)
Greetings, Facundo!
Just to let you know, i got it as "pasta de pulir", "polishing paste" in Argentina, maybe is useful for someone else :)
https://articulo.mercadolibre.com.ar/MLA-699143506-kit-pulir-pano-suelto-7p-pasta-brillo-blanca-_JM#redirectedFromParent
can a person just use regular partical board for doing this or does have to be "medium density"?
I don't know how reliable low density board would be. My concern with the radial forces and the possibility of pieces coming loose. Prefer MDF or HDF.
Could I rewire the grinder in reverse so I have easy access to the on/off switch?
Hi Deano,
It entirely depends on what wires are available motor terminals. Some motors bring out the capacitor and start winding wires, while others only the capacitor wires and one start winding wires (cost savings for the manufacturer). It's not simply a matter of swapping the power leads. A capacitor is generally used to determine the rotation and the changing the incoming power has no effect.
There is another consideration. The arbor nuts are threaded so that they maintain tightness when the motor spins in the intended direction. Running the motor in reverse would encourage them to loosen off.
Dan
Just reverse the base of the grinder..should only be held on with 4 screws or bolts.
Unfortunately, this type of grinder is not the normal motor on a base model like most popular brands.
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