using the SB-250 and SG-250

[Ken S]

I recently used my SB-250 grinding wheel to sharpen my kitchen knives. I was pleased with the way it worked. It was my first positive experience with the blackstone.

Today I ground a long bevel on the piece of steel I am using to make a jig to help set knife angles. I needed to grind a bevel with an angle more acute than fifteen degrees on a piece of steel one inch (25mm) wide. The steel was "welding steel", I suspect just regular carbon steel. I found the SG-250 cut much more quickly than the SB-250. This was not a surprise; Tormek has always said the SG is the preferred grinding wheel for regular steel, the SB being designed for harder steels.

I will continue to use the SB for knives and harder steels. It is nice to have a choice.

Ken

[That Sharpening Guy]

It is time for me to buy a new stone. I am wanting to get the SB-250 because I sharpen a variety of knives both hard steel and and regular stainless.

Do you notice a big difference on how quickly you get a bur using the SB-250 compared to the SG-250?

Will the SB-250 clog up when sharpening soft metals?

Will it last longer than the original stone?

I do not use jigs only freehand when sharpening knives.

Thanks!!

[OBR]

I've been sharpening knives every Saturday at our local farmers' market using a new SB-250 that I installed this June. Since then I've sharpened 935 knives and a couple dozen pairs of scissors. The SB-250 has worn to a SB-195, and I will probably have enough left to continue until the market ends right after Christmas. I use the knife jigs and sharpen both stainless and non stainless knives. I keep the SB at the 1000 grit stage, and at that grit I've been able to even regrind knives that have nicks. I do have to retrue the SB after every 75 to 100 knives because it starts to go out of round. I keep wondering if I have some flaw in my technique that causes the stone to go out of round, but I'm pleased to be able to sharpen a 1000 +/- knives from one stone.

[Ken S]

Excellent post, OBR.

Sharpening Guy,

I would suggest adding the SB-250 before you reach the end of the useful life of the SG-250. That would allow some side by side comparison. I have heard a lot of good comments about using the SB with knives.

On the other hand, when I ground the bevel on my new angle tool (regular carbon steel), the SG was noticeably faster. (Another reason to add the SB while you still have some life left in the SG.)

Ken

[That Sharpening Guy]

Thank you for the feedback!

[Herman Trivilino]

I have used nothing but the SG. However, I have watched closely to see what others have reported on the use of the SB (and the SJ, too).

Based on what I've seen, the best reason to choose the SB (or the SJ) is if there is something specific about the SG that you're not happy with and you think the issue can be addressed by switching.

The SB will likely last longer, but I don't think it will offer the same level of versatility. For example, switching between coarse and find grades takes longer.

[Herman Trivilino]

I keep the SB at the 1000 grit stage, and at that grit I've been able to even regrind knives that have nicks.

So, you never apply apply the coarse side of the stone grader to your SB grindstone? How do you keep it clear of steel particles? I would think it would clog up doing that.

And, how do you restore it to the 1000 grit stage after truing? Don't you find it very coarse until after you've reshaped a chisel or the like?

[OBR]

I usually retrue the stone during the first half hour of our market before customers start bringing knives in. The sound of the truing reminds early customers that I am open for business. Once the stone is true again, I make a very SLOW very LIGHT final pass. Generally I'm set to sharpen at that point; but if the stone still feels rough, I'll lightly dress with the stone grader. I've never experienced any difficulties caused by metal particles. Next Saturday I'll bring a magnet to the market and check periodically for metal particles. What kinds of problems do you think metal particles might cause?

Curt

[Herman Trivilino]

My only experience is with the SG grindstone. Metal particles clog it up and it won't grind anymore. It needs to be refreshed with the coarse side of the stone grader. Follow that with the fine side and it's good for only a short time. I have to keep refreshing it.

[That Sharpening Guy]

Thank you for the the advice. I just went with the SG-250 stone. When I am financially able I may purchase the SB-250 also for when I really need it.

[Ken S]

I don't think the SG-250 original, general purpose wheel is ever a bad choice. In some instances, the SB-250 blackstone may be a better choice.

Ken