An informal review of using Congress Tools triangle Moldmaster sharpening stones with Sharpmaker (SM). The goal was to experiment and try to find improved sharpening options for high vanadium steels compared to the add-on SM diamond and CBN rods. These rods are fragile, are only offered in a single grit (about 400 mesh), and have bumpy surfaces due to the coated abrasives. I know a lot of folks like them, but I never did, so I was curious to experiment and see if there are alternatives that could sharpen these hard steels, would offer a range of grit options, and would also provide a smoother, more manageable sharpening stroke.
Stones: purchased from Congress Tools
I tested the following progression of grits on a Spyderco Mule Team knife in 20CV, and a Benchmade in S30v: 240, 400, 600.
Observations:
Are there downsides:
Recommendations:
Stones: purchased from Congress Tools
- Moldmaster silicon carbide (SiC) stones. These will cut the high vanadium super steels. Available in these grits: 80, 120, 150, 240, 320, 400, 600. I tried the 240, 320, 400, and 600. My logic here in not getting lower grits is it's VERY difficult to do serious blade profiling on a tool like SM due to the narrow width of the stones and the v-crock design. For me, I wouldn't try to bother with serious edge profiling on SM. If I need that, I'd go to a bench stone. I just wanted grits coarse enough to do moderate edge repair, maybe reset my edge without a total reprofile, and give me a good toothy edge. For that, I found the 240 grit worked great as a starting point. Somebody might want to go lower and try the grits in the 100's. I wanted to work up through their highest grit, 600, so I could test and see if they had a good "fine" finishing option that would be better than what's available on SM today.
- Flex AlOx stones. The Flex 600 grit, also the highest grit available in that stone, is supposed to be a polishing stone. I tried it and it did add some polish to the edge after sharpening on the other grits. However: AlOx is probably not optimal as a finishing material for high vanadium steels. This has been discussed elsewhere. Also, using this stone did not in any way improve the sharpness or observable cutting performance above what I could get on the 600 grit Moldmaster stone. So IMHO, this stone doesn't add a lot to the equation if you are sharpening modern super steels on SM.
I tested the following progression of grits on a Spyderco Mule Team knife in 20CV, and a Benchmade in S30v: 240, 400, 600.
Observations:
- Sharpening on these stones was easier to manage the stroke, and noticeably smoother, than sharpening on the Spyderco diamond rods (which I have). I'd prefer using these stones if using SM to sharpen super steel blades.
- The 240 grit cuts reasonably fast and I was able to reset the Mule Team edge in minutes. It would be a reasonable coarse grit to work with on the SM, but if you want to really go for it and try to profile edges on SM a lot, I'd go for the 150 or 120.
- After doing only about 5 strokes per side on the 400 grit, and then the 600 grit, I had a nice clean consistent looking edge on both knives. It was extremely sharp and would push cut all the way through newsprint from top to bottom without stopping in the page. These SiC stones got amazing results on this hard 20CV blade, and fast!
- I don't see the 320 as adding much here, unless you were just trying to get a "tweener" grit that would do it all so you don't need as many stones. Which is fine, but if you do that, you may as well stick with the SM diamond or CBN stones which are 400 mesh. But again, subject to individual needs.
Are there downsides:
- Sure, always, with every option. I have only tested these on 2 blades, S30v and 20cv. So this review is limited in scope and I don't know how they'd do on ALL modern super steels, or on tool steels. Sorry, I only have so much time, money for buying stones, and test blades to mess with.
- The stones are SiC, and will likely wear fast. So you'd need to buy an inexpensive diamond plate or something to lap them and keep them flat. And eventually buy new stones, as well.
- They would cost extra $$ over your included SM stones. Say you bought a pair each of the 240, 400, 600 Moldmasters I suggested. Total cost for those 6 stones: $36.60, plus shipping. I also don't know how long they'd last or how well they hold up, since I just got mine.
Recommendations:
- After trying this, if I was going to use my SM to do a lot of sharpening of super steels, I would personally get a pair of Congress Tools 1/2" triangle Moldmaster stones in each of these grits: 240, 400, 600. For ordinary maintenance sharpening, I'd use the 400 and finish on the 600. You get phenomenal results, fast, on only 2 grits. For significant grinding on the edge, I'd add a pair of 240, or perhaps 150 grit, stones to the equation.
- If you want some kind of polishing stone to finish, I'd use a few SUPER light strokes per side on your Spyderco fine or better yet the Ultrafine ceramic rods to finish after sharpening on the Moldmasters. IMHO, this step is not necessary though for sharpness and adds little. I would personally view the Moldmaster 600 grit as a perfectly fine finish stone, it gets great sharpening results and the edge looks fine as you can see from the pics below.
- Bottom line: These are a really interesting alternative to the Spyderco stones, that would address SOME of their limitations, and give you a way to sharpen modern super steels effectively on SM. I'm not going to recommend people should go buy these, as I haven't used mine long enough to figure out all the limitations. However, they do work super well, and if I used my SM a lot, I would definitely invest in these Moldmaster stones and use them. In fact, though I've gone almost totally freehand sharpening, I plan to round out my set so I have a pair each of the 240, 400, and 600 as I suggested.
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