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lapped and dressed my Arkansas stones

I lapped and dressed my two Arkansas whetstones that I purchased from Dan's. The two stones: Black Arkansas (Ultra Fine), Hard Arkansas (Fine). They were not flat (especially the Hard Arkansas). I started by marking the surface that I was lapping with a red sharpie. I also put an arrow on the edge to point to the surface I was treating. I only lapped one side of each stone.

I purchased the "Small Rotary Grit Pack" from The Rock Shed. To lap the stones, I used 60-90 grit SiC powder, with water, on top of a steel cookie sheet, on top of the concrete garage floor. I lapped until the red markings were gone. Then I marked again and ran the stone over the grit to confirm it was flat. I continue with the 120-200 SiC powder and then the 500.

I switched to the w/d sandpaper. I had a spray bottle of soapy water. I sprayed the stone then rubbed the surface with the sandpaper. I started with 600 grit on both stones. Then on the Black Arkansas, I used 800 grit followed by 1000 grit.

One note regarding the cookie sheet. After a while it would bow up in the middle, so I had to press down to keep it flat. Eventually, I put a stack of ceramic pots on it to make it easier to hold down (reducing usable area but also reducing the amount of work). End-to-end it took a couple of hours. I would rinse out the cookie sheet and bucket of rinse water for every change in grit when using the SiC powder.

Final note, I had a hell of a time finding SiC powder in the grits that I wanted. My first order Cutting Edge Supply was a disaster (long story short, it took almost a month to get it, and then it wasn't what I ordered). The Rock Shed was much better and prompt. The grits they have didn't match what I wanted in all cases but was good enough. My order from Cutting Edge Supply was on 15-Nov and my order from The Rock Shed came in yesterday (20-Dec). The Rock Shed was good at getting the order in the mail, but it was "in the network" for a while before it finally emerged a couple of days ago.
 

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Hope it works out for you. Latest collective advice from the experts here seems to be to lap things on the black hard to 600x, although a few years back, they were for 1000x-2000x so go figure. For the hard Ark, I would suppose something well short of 600x. Both stones look delicious. What format are we talking about here? In lapping, I've used the lower silicon carbide loose grits on one side of a 1/4" thick piece of plate glass, followed by the w/d sandpaper for the finer grits on the other side, and this has worked out well for me on any given counter top.
 
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Hope it works out for you. Latest collective advice from the experts here seems to be to lap things on the black hard to 600x, although a few years back, they were for 1000x-2000x so go figure. For the hard Ark, I would suppose something well short of 600x. Both stones look delicious. What format are we talking about here? In lapping, I've used the lower silicon carbide loose grits on one side of a 1/4" thick piece of plate glass, followed by the w/d sandpaper for the finer grits on the other side, and this has worked out well for me on any given counter top.
By "format", what do you mean?
 

rbscebu

Girls call me Makaluod
I'm wondering why the cookie sheet started to bow up in the middle. The only thing I can think of is that somehow the sheet's upper surface was expanding.

I use a polished granite slab as a base for lapping. To protect the granite surface from dishing due to the wear from the SiC powder, I first put a sheet of W&D down onto the slab and then sprinkle the powder onto the W&D. The W&D grit rating needs to be the same or finer than the SiC powder.
 
One benefit of lapping up to 600 grit is that there is just enough polish beginning to develop. This makes it very easy to see unevenness in the surface. But at 600 grit you haven’t taken the surface so far out that it becomes a real headache to go back if you need to.
 
I have lapped many Arks on the same steel cookie sheet without issue. The trick is to get to flat using 60 grit loose Silicone Carbide. Stay on the 60 grit until you are absolutely sure you are flat.

Slurry will wash off pencil and sharpie ink and the stone is still not flat. If you grid mark with sharpie and it comes off completely in less than 10 laps, you are probably pretty flat. I do that test 4-5 times once I think I am flat.

Once you are flat you can run up the grits quickly, minutes on each grit, you can feel and hear when the stone face gets smooth.

Recently I have tried a different technique, using 60 grit Diamond powder, eBay $15, and Silicone Carbide, coarse Crystolon stones. lay the Ark flat and sprinkle a bit of 60 grit diamond on the stone, then with pressure rub the coarse Crystolon on the diamond and stone. A sharpie grid will show your progress. The grit imbeds in the Crystolon and acts like a diamond stone.

This is at least twice as fast a Silicon Carbide. It also works with 60 grit loose Silicone Carbide, but not as fast as diamond.

Got Grit.com is where I buy my Silicon Carbide, $15 will get an assortment of grits from 60 to 500. Shipping is fast and cheap.

Once flat you can quickly and easily alter the stone face similar to Wet &Dry grits using different Crystolon and India, (aluminum oxide) stone grit faces. A fine India leaves a similar finish to 600 grit on an Ark.

India stones, (Aluminum Oxide) cut finer than the same grit in Silicon Carbide, Crystolon stones and much finer than the rated grit.

Experiment with different stone faces with Wet & Dry and India and Crystolon stones. Be sure to bevel or round your stone edges, they can get sharp.
 
I bought my SIC powder from Tom at GotGrit, as per Marty's (@H Brad Boonshaft's) recommendation.

I bought multiple grits but ended up only using the 220-grit SIC to lap a Norton No. 1 Washita and a Norton Hard Translucent HB6. Worked great!

I am not convinced that you need lots of different grits. The stuff breaks down quickly. My theory is that broken down 220-grit produces a finish significantly finer than 220. How much finer, don't know. All I can say is I like the finish.

Turns out that Tom's parents lived on the same street that I live on. Small world, right?
 
I'm wondering why the cookie sheet started to bow up in the middle. The only thing I can think of is that somehow the sheet's upper surface was expanding.

I use a polished granite slab as a base for lapping. To protect the granite surface from dishing due to the wear from the SiC powder, I first put a sheet of W&D down onto the slab and then sprinkle the powder onto the W&D. The W&D grit rating needs to be the same or finer than the SiC powder.
Removing steel from the cookie sheet causes stresses to be revealed in the steel, the now thinner steel is free to distort.

I do it much like you and my granite slabs have stayed flat. I generally use worn paper, there are probably better options but it seems to work just fine. I use sink cut outs from granite counter tops, they are free.
 
I lapped and dressed my two Arkansas whetstones that I purchased from Dan's. The two stones: Black Arkansas (Ultra Fine), Hard Arkansas (Fine). They were not flat (especially the Hard Arkansas). I started by marking the surface that I was lapping with a red sharpie. I also put an arrow on the edge to point to the surface I was treating. I only lapped one side of each stone.

I purchased the "Small Rotary Grit Pack" from The Rock Shed. To lap the stones, I used 60-90 grit SiC powder, with water, on top of a steel cookie sheet, on top of the concrete garage floor. I lapped until the red markings were gone. Then I marked again and ran the stone over the grit to confirm it was flat. I continue with the 120-200 SiC powder and then the 500.

I switched to the w/d sandpaper. I had a spray bottle of soapy water. I sprayed the stone then rubbed the surface with the sandpaper. I started with 600 grit on both stones. Then on the Black Arkansas, I used 800 grit followed by 1000 grit.

One note regarding the cookie sheet. After a while it would bow up in the middle, so I had to press down to keep it flat. Eventually, I put a stack of ceramic pots on it to make it easier to hold down (reducing usable area but also reducing the amount of work). End-to-end it took a couple of hours. I would rinse out the cookie sheet and bucket of rinse water for every change in grit when using the SiC powder.

Final note, I had a hell of a time finding SiC powder in the grits that I wanted. My first order Cutting Edge Supply was a disaster (long story short, it took almost a month to get it, and then it wasn't what I ordered). The Rock Shed was much better and prompt. The grits they have didn't match what I wanted in all cases but was good enough. My order from Cutting Edge Supply was on 15-Nov and my order from The Rock Shed came in yesterday (20-Dec). The Rock Shed was good at getting the order in the mail, but it was "in the network" for a while before it finally emerged a couple of days ago.
How fare out of flat were the stones when you started?
 
I bought my SIC powder from Tom at GotGrit, as per Marty's (@H Brad Boonshaft's) recommendation.

I bought multiple grits but ended up only using the 220-grit SIC to lap a Norton No. 1 Washita and a Norton Hard Translucent HB6. Worked great!

I am not convinced that you need lots of different grits. The stuff breaks down quickly. My theory is that broken down 220-grit produces a finish significantly finer than 220. How much finer, don't know. All I can say is I like the finish.

Turns out that Tom's parents lived on the same street that I live on. Small world, right?
Dang! I should’ve gone to Got Grit.

Regarding which grit, once I saw that my stones where not flat, and given they were the hardest Arkansas stone one can get, I dropped down to the 60/90. I’m glad I did. It took a lot of work to flatten them out.

I like what you are saying regarding how the material breaks down as you use it. I noticed this as well.
 
Removing steel from the cookie sheet causes stresses to be revealed in the steel, the now thinner steel is free to distort.

I do it much like you and my granite slabs have stayed flat. I generally use worn paper, there are probably better options but it seems to work just fine. I use sink cut outs from granite counter tops, they are free.
Good explanation!

I liked the cookie sheet because the raised edges contained the slurry, and it was easy to rinse out when changing grits. The warpage was manageable.
 
How fare out of flat were the stones when you started?
I’m not sure how to quantify this. I didn’t do a light test — just sharpie on stone followed by grinding it down.

The Black wasn’t too bad, but I did immediately switch to 60/90 once I saw it (I started with 120/220).

The Hard was low in the center of the surface. It took a lot of work to edges down. This is where I spent most of my time.

Given that I only lapped one side on each stone, it does show me the difference between the treated and untreated surfaces. I wish I’d done it sooner!
 
Whetting my John & William Rag on the Arkansas Black in oil was a dream! Lapping and dressing the stone made a big difference.

Assuming the stone was ready for use because it was from Dan’s was a mistake. I guess buying from Dan’s means the stone is a good quality. Lapping a dressing is still required, however, for one to take proper ownership.

I am much more confident in the use of the this stone knowing it’s flat and that if I want to change its dressing, I can do that.
 

duke762

Rose to the occasion
I've never tried the cookie sheet method but can understand the attraction to keeping any messes under control. I find the bowing to be a bit of a worry however. I can't wrap my head around how flatness can be achieved with something un-flat pushing back at you while you work. Am I over thinking this? Seems to me it would tend to want to crown the stone.

My cheap, workhorse abrasive for heavy lifting is silica sand. Grits this low seem to remove material with a rolling action under the stone, causing erosion by micro chipping or pitting and not the scratching/cutting action associated with fixed abrasives. And I do love how they break down and end up punching above their weight.
 
This thread brings back cold dark memories of me on my hands and knees on my kitchen floor during demented, frantic, endless scraping sessions, the deafening metallic growling/screaming of 60 grit silicone carbide powder. Constant rinsing, checking, straight edges, sharpie grids, getting nowhere ,not making a dent, sore knees, angry girlfriend, what fresh hell is this? bath full of silicone carbide slurry and scraping scraping scraping. Sheet after sheet after sheet of wet and dry, no avail, back to the SC. What kind of crazy, mighty geological forces even formed this stuff? I grappled with this rock through many a night and many a day, went crazy like Ahab with monomania fighting my own whale but mine was black not white and was 6 inches long x2 inches wide.
Finally, after fighting it every tiny step of the way, every atom by every atom it appears flat and gives a lovely edge. Was it worth it? I’m still too damaged to know.
 
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People are going to wince, but, I bought a hard black arkansas for about $0.50 at an estate auction. It was seriously cupped to the center. I used the old fashioned turn a hose on a piece of concrete, and did circular rubbing. In aboutr 20 min I had a flat surface.
People are going to argue I ruined the surface, but what I've been taught is that on an Arkansas stone, it's the pieces that break off into the slurry that actually does the sharpening. I did final polishing on a couple of jack knives before I gave it away at Christmas. I got a hard translucent in a larger size.
 
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