OK, here is how I do it. I have already told everyone that NASA Bill was a professional scientist sharpener for 3M company. He fixed the lenses on the Hubble space telescope, and he also sharpened the diamond cutter bits that make the lenses. As he is also expert is optical lenses so he knew exactly how to measure the hollow in Clipper blades. Here is how he told me to sharpen 5 in 1 blades and also ceramic blades.
First you have to have a true flat rub block. Cast iron is the best for this type of sharpening. I use the Andis rub block with the handle. To make the diamond slurry you will need either mineral sprites of if you have a True Value hardware store near you, you can buy Sunny Side Odorless Paint thinner) The latter is really just mineral spirits except it has zero odor.
First squeeze out about 1/8” of 3-micron diamond paste onto the rub block it will be about the diameter of a toothpick so you don’t need much. Then use your finger and dab it evenly over the face of the rub block. Then with a squeeze bottle lay down a 1/2 “wide strip of the thinner, and then rub it all together to make the diamond slurry.
You are ready to sharpen. I sharpen the comb on the outer edge of my clipper wheel, then clean it. Also clean the cutter, but do not put the cutter on the clipper wheel, just clean it. I then take the clean cutter, and do circular motions all over the face of the rub block in right and left circles, and then finish up with forward and back motions. This all takes about 1 minute. I then do the same to the cleaned-up comb that I sharpened on the outer edge of my clipper wheel. Takes another minute using the same method. Clean the comb, and the cutter one more time. I usually tweak the two wire spring wires forward just a tad, not too much! Then attach the cutter to the plastic platform, and oil both the cutter and the comb. Assemble and test. Cuts better than new! Plus, so far, I have never worn out a cutter! The comb will wear out before the cutter will because of sharpening it on the clipper wheel. After a couple of sharpening on the comb you need to round the tips of the comb as they will begin to get just a sharp as a 40 blade tips so round them same as a 40 blade and your customers will love you.
Ceramic cutters are sharpened the same but require more sharpening then the 5 in 1 blades. Instead of 1 minute try sharpening them for 3 minutes for the same results.
That is all great and everything, but the most important thing is the condition of your rub block. If it is not perfectly flat then this process may fail. Don’t think because you have a new or fairly new rub block that you are ready to sharpen using this method. Even a new rub block may not be perfectly flat. Mine wasn’t, it was low around the edges. How do I know that? Here is how. Hopefully you have a flat diamond bench stone like what DMT sells? I used the 1200 grit side of mine. Using it dry, I rubbed the 1200 grit diamond hone on the face of my rub block and it made a pattern that was oval shaped in the center of my brand new Andis rub block. This showed me that the edges of the rub block were lower than the oval center that was flat. So, it turns out that if I stay in the flat area that I would be OK, but if I go past this flat area then things will start going south.
To solve this problem, I found a company near me that has machines that will perfectly flatten the full face of my rub block. After they did that then I had a perfectly flat rub block over the full face of the rub block. The reason it is important to do this before putting diamond paste on your rub block NASA Bill told me that the diamonds will immediately start to impregnate the face of the cast Iron rub block, so it needs to be perfect before you begin. So, I guess as the saying goes; News flash! Rub blocks are not perfect! Even new ones.
As you use the rub block for sharpening 5 in 1 blades, and also ceramic cutters. The diamonds will continue to impregnate the face if the rub block. This means that your rub block will never wear out! So now you see why it is so important to make sure your rub block is perfect before you begin. NASA Bill has been using his same rub block for over 25 years and it is still as flat as the day he bought it. His particular rub block is large, and cost a lot of money and it was perfect when it was new as it still is today.
The obvious question now is; Will it still work for doing rub patterns? the answer is a resounding yes! It will work even better because the diamonds will show the patter clearer as time goes on. Before I did all this, I had two rub blocks. One always had a perfect football pattern when I rubbed it. The other one always had a straight across rub pattern, and sharpening on the same clipper wheel on the same exact sweet spot for both rub blocks. That told me that it was the rub blocks and not the clipper wheels that was determining the rub patterns in this particular case. After getting both rub blocks trued up, they both rubbed the exact same football shaped rub pattern. So, then I began sharpening NASA bills way, and I have to say my customers are very pleased.
One more thing. A sharpener brought me his rub block to try and flatten on my true flat clipper wheel. We used 180 grit and sharpened the face of the rub block same as a large clipper blade. This helped, but did not make it perfect as you might suspect. However, he did get better rub patterns after we were done. Before we did this operation, I tested the face of his rub block using the DMT 1200 grit diamond hone, and it showed a nice oval ring. The center, and the outer edges of the oval ring was lower than the ring itself. In other words, the rub block was useless, and needless to say it was completely worn out. Don’t put diamonds on a worn-out rub block or even one that is not perfectly flat because the diamonds will never come out of the cast iron causing it to never wear out. Wouldn’t it be worth it to make sure your rub block it perfect before making it immortal?