OhioApexing
Sharpener
- Joined
- Apr 17, 2018
- Messages
- 235
I recently picked up some Poltava Diamond Tools metallic-bond diamond and metallic-bond CBN stones, in addition to some resin-bond CBN stones. They were purchased with ease and great customer service from Practical Sharpening. They're all fantastic, but I truly love the metallic-bonded CBN stones and promptly ordered four more to add to my rotation.
The common practice for lapping/refreshing the metallic-bond stones seems to be an etch with ferric chloride, which kept me away from trying them until I began using FC to acid/stonewash knives for clients. It is a really straightforward process, but I digress.
The ferric chloride does an excellent job of exposing fresh abrasive but I became concerned with flatness over time, especially as I was looking to mount the stones on EP blanks (the metallic-bonded stones come unmounted from Practical Sharpening so that each side of the stone can be used, the resin bonded stones are mounted).
I did a bit of digging on Poltava’s website and found that they recommend vitrified-bonded silicon carbide to dress/true their metallic-bonded wheels:
https://pdtools.com.ua/en/inform_po...he-use-truing-and-dressing-of-diamond-wheels/
Not having vitrified-bonded SiC at my disposal, I decided to try loose silicon carbide on glass in an even, fairly heavy application. I expected it to be an extremely arduous process but was very pleasantly surprised.
I decided to go after the 100-grit (JIS) metallic-bonded diamond, the 150-grit (JIS) metallic-bonded CBN, and the 300-grit (JIS) CBN.
For the 100 and 150 grit, I used 60-grit (FEPA) and worked it until the grains had broken down into an even, relatively fine layer across the glass. I did the same for the 300-grit stone but finished with 120-grit (FEPA) SiC to finish the surface. I spent maybe 60 seconds on each side of the stones. Here are before/after results -- the uneven coloration in the last photo is due to the stone not yet being completely dry:
Conclusion: I have yet to sharpen with them since lapping, but I got them mounted to Gritomatic blanks. The stones feel great to the touch and seemed very flat when placed on the back of my Atoma 400 bench stone. I wish I had gotten the before/after measurements with my calipers to see what kind of material loss I incurred but eye-test says that it was nominal at best. I noticed no appreciable loss. I'll try to remember to follow up after use. For now, I see loose SiC on glass as being a viable alternative to ferric chloride etching as a means of truing the stones. I may use continue to use FC to expose fresh abrasive as needed (as I would use a nagura on resin-bonded stones) and SiC to bring them back flat as needed.
The common practice for lapping/refreshing the metallic-bond stones seems to be an etch with ferric chloride, which kept me away from trying them until I began using FC to acid/stonewash knives for clients. It is a really straightforward process, but I digress.
The ferric chloride does an excellent job of exposing fresh abrasive but I became concerned with flatness over time, especially as I was looking to mount the stones on EP blanks (the metallic-bonded stones come unmounted from Practical Sharpening so that each side of the stone can be used, the resin bonded stones are mounted).
I did a bit of digging on Poltava’s website and found that they recommend vitrified-bonded silicon carbide to dress/true their metallic-bonded wheels:
https://pdtools.com.ua/en/inform_po...he-use-truing-and-dressing-of-diamond-wheels/
Not having vitrified-bonded SiC at my disposal, I decided to try loose silicon carbide on glass in an even, fairly heavy application. I expected it to be an extremely arduous process but was very pleasantly surprised.
I decided to go after the 100-grit (JIS) metallic-bonded diamond, the 150-grit (JIS) metallic-bonded CBN, and the 300-grit (JIS) CBN.
For the 100 and 150 grit, I used 60-grit (FEPA) and worked it until the grains had broken down into an even, relatively fine layer across the glass. I did the same for the 300-grit stone but finished with 120-grit (FEPA) SiC to finish the surface. I spent maybe 60 seconds on each side of the stones. Here are before/after results -- the uneven coloration in the last photo is due to the stone not yet being completely dry:
Conclusion: I have yet to sharpen with them since lapping, but I got them mounted to Gritomatic blanks. The stones feel great to the touch and seemed very flat when placed on the back of my Atoma 400 bench stone. I wish I had gotten the before/after measurements with my calipers to see what kind of material loss I incurred but eye-test says that it was nominal at best. I noticed no appreciable loss. I'll try to remember to follow up after use. For now, I see loose SiC on glass as being a viable alternative to ferric chloride etching as a means of truing the stones. I may use continue to use FC to expose fresh abrasive as needed (as I would use a nagura on resin-bonded stones) and SiC to bring them back flat as needed.
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