Uh oh - this can't be good...

[texaspro]

Fired up the Jap stone today and after polishing for about 3 - 4 mins, I noticed of my marker mark was not being removed on the heel of the knife, but was everywhere else. I checked the truing and the right side was out of true. I've only used this stone one knife...So, I looked in this forum to make sure the truing tool can be used on the Jap stone and saw Mr. Farris had said, "yes". So, I took a tiny bit off the top. Once I got to that side of the stone, I could hear and feel the raised portion much more. It was working great, but at the end, there was a pop and I saw chunks come off. This is what it looks like now...What now?

[texaspro]

Quick update: I'm returning the stone and ordering a new one. Something must not have been right from the start...

[RichColvin]

Not uncommon.  I've seen that it happens when you take off too much too fast.

Kind regards,
Rich

[Ken S]

I am a great believer that you should be completely satisfied with every Tormek accessory. As you have lost cinfidence in your SJ-250, you should return it.

When you have your replacement wheel, I highly recommend the "slow and steady" truing method that I use. I set the TT-50 such that the first pass barely kisses only the highest point of the grinding wheel. If, by chance, no part of the wheel touches the diamond, that is OK.

For the second pass, lower the diamond only HALF of a number on the microadjust. Advance the diamond slowly, taking at least ninety seconds for each pass. Continue lowering the diamond only half a number on subsequent passes. Watch the grind pattern. When you reach the point where you grind a little away from the entire width and circumference of your grinding sheel, stop. Continuing beyond this point will only waste wheel.

I prefer to true gently and often. I don't think frequent light truing uses any more wheel diameter then infrequent heavy truing, plus your wheel will run more true. I have not chipped a wheel using this method.

Keep us posted.

Ken

ps I don't think it would be unreasonable if, because of the small size of the chipping, your dealer suggested that you try truing the wheel (very gently) again. If you don't experience any further chipping, the wheel is probably OK. The suggestion should include a promise to exchange the wheel if you experience any more chipping.

[cbwx34]

There's been a couple of threads that talk about the SJ wheel chipping while truing.  I found one HERE... I thought there was another, but can't find it right now.  But may have to be something to solve before  you true another SJ stone...

Also, I suggest chamfering the edges... just like done on a regular waterstone.

[Ken S]

Good thought, CB. I like youe edge chamfering idea.

Ken

[GKC]

There's been a couple of threads that talk about the SJ wheel chipping while truing.  I found one HERE... I thought there was another, but can't find it right now. 

The link that CB provides above takes you to a thread with a post from Wootz that itself has two further links, including one to a typically detailed post by Wootz himself.

By the way, from picture that texaspro posted, I think that the stone has only lost a millimetre or so in diameter, I think it could be fully restored with the sort of slow and gentle approach discussed in this thread and with the special care discussed in the threads that CB linked to.

Gord

[texaspro]

There's been a couple of threads that talk about the SJ wheel chipping while truing.  I found one HERE... I thought there was another, but can't find it right now.  But may have to be something to solve before  you true another SJ stone...

Also, I suggest chamfering the edges... just like done on a regular waterstone.

Thank you. Good info there. Thanks again Tormek Community!!

I also had someone tell me on another forum to let it either run on the wheel or soak in water for an hour before truing. Seems excessive, but for a $400 stone, I'll try it.

BTW, I went super slow.

Also, I see now that it is not uncommon. Fortunately, it was a quick exchange. New stone should be here later today. If it happens again, I'll chamfer it. That could actually be useful on some exotic blade shapes, now that I think about it.

[Ken S]

The hour run or soak time seems overkill to me, HOWEVER, I always leave my Tormek long enough for the stone to complete its absorbtion. I fill the water trough first and let the Tormek idle while placing the tool in the jig. Two minutes should do the trick, adding more water gradually as needed.

Incidentally, in case you have not already encountered it, get a turkey baster and a couple empty plastic jars. (I use peanut butter jars.) The baster makes removing water from the trough "a treat" as our UK friends might say. This simple trick will eliminate most of your water spillage. It's an idea from another forum member.

Ken

[RichColvin]

Chad,

I agree with Ken, and especially in regards to the SJ stone.  I've not found that it absorbs much water anyway. 

Kind regards,
Rich

[texaspro]

The hour run or soak time seems overkill to me, HOWEVER, I always leave my Tormek long enough for the stone to complete its absorbtion. I fill the water trough first and let the Tormek idle while placing the tool in the jig. Two minutes should do the trick, adding more water gradually as needed.

Incidentally, in case you have not already encountered it, get a turkey baster and a couple empty plastic jars. (I use peanut butter jars.) The baster makes removing water from the trough "a treat" as our UK friends might say. This simple trick will eliminate most of your water spillage. It's an idea from another forum member.

Ken

So you're taking the "stone" water out with the baster and re-applying it onto the stone? I have heard of guys keeping the "slurry" and using it for preservation of the SJ.

BTW, fellas, thanks a ton for all your help. This community is fantastic. I'm obviously a newb and you guy have treated me with dignity and grace. A+

[Ken S]

The baster is used when you are cleaning up at the end of the sharpening session. I have found that dumping the water from the trough is when most of the water spillage occurs. Using the turkey baster eliminates the mess. Evacuating most of the (clear) water leaves only the sludge in the trough, which is easily wiped out with a paper towel and discarded, thus keeping the drain clear.

Ken

[RichColvin]

To elaborate on Ken's answer a bit, for the T-2000 and T-7, the water trough hangs on tabs.  To remove the trough, you have to lift it first.  If it is full, the water will easily spill out.  That is the beauty of using the turkey baster to remove some of the water first.

I'm not familiar with the T-8's hold on the water trough :  may not be a problem for that machine.

Kind regards,
Rich

[Ken S]

To add to Rich's reply:

The water trough on the T8 is held in place by magnets. It is released by pivoting the bottom away from the frame. It is a good design. With a turkey baster, it is a better design.

Ken

[bisonbladesharpening]

I find that puzzling.  I have a T-8 and the only magnet is on the scraper.
The water bin is held in place by 2 tabs that come out of the frame and is raised
or lowered by a knob.  Was there a change made to later models T-8's ?