Anyone have a SG250 stone with about 200 mm left?

[John S]

I am looking for a stone to replace my badly chipped SG200. Mine cannot be saved.  Contact me off list and we can work something out.  I'm im Ohio.

[RichColvin]

Contact Steve Bottorff. His web site is SharpeningMadeEasy.com.  Steve lives in Northern Ohio and may be able to hook you up.

[Ken S]

I think this is an excellent idea. A 250mm wheel worn to 200 mm has used its best days with a larger Tormek, but is just coming into its own with a T4.

Ken

[Nosetotail]

How does it fit?  It is 2" and the 200 is 1.5".

[cbwx34]

How does it fit?  It is 2" and the 200 is 1.5".

I didn't think it would fit,,, but it does without any issues.

https://forum.tormek.com/index.php?topic=3344.msg20259#msg20259

[Ken S]

The side indent of the 250mm wheel is greater than the side indent of the 200 mm wheel. Between the indent difference and a little extra length of the threads on the shaft, either size wheel can be mounted on any of the Tormek models.

Ken

[RichColvin]

Here are some details:  http://sharpeninghandbook.info/Grindstones-StoneLife.html


Kind regards,
Rich

[Ken S]

Rich,

Your Sharpening Handbook is a valuable resource for us. And, your entry about Tormek wheels is useful, as far as it goes.  However, I believe it leaves out some key information.

I became aware of the interchangeability of 200 mm and 250 mm grinding wheels when I first purchased my BBN wheels from D-Way. All of the D-Way CBN wheels in all sizes share a common bore diameter of one inch. D-Way manufactures several nicely machined steel reducing bushings. This allows one wheel to be used with grinders with different bores.

I was surprised to see that the same steel reducing bushing worked with both diameters of Tormek wheels. With your dimensions, it would be useful to note that sizes of Tormek models have shafts which share a common length of shaft for the section which holds the grinding wheel and the same thread length. The thread length is long enough to compensate for the slight difference in thickness between the two wheel sizes.

The majority of the difference is absorbed by the difference in the inset of the one side of the wheel. This can be problematic with non Tormek wheels with the recess; the shaft is not long enough to thread well with non standard wheels.

I disagree with trying to use up the last millimeter of wheel size. This is not just my opinion. In this video, Tormek expert, Terry Beach, discusses why he only uses his wheels down to 220mm.  (last minute of the video) Here is the link:

https://youtu.be/8zQDmQ_n7wg

Personally, I would not want to pay for a knife sharpening with so much hollow in the grind.

Ken

[cbwx34]

...
I disagree with trying to use up the last millimeter of wheel size. This is not just my opinion. In this video, Tormek expert, Terry Beach, discusses why he only uses his wheels down to 220mm.  (last minute of the video) Here is the link:

https://youtu.be/8zQDmQ_n7wg

Personally, I would not want to pay for a knife sharpening with so much hollow in the grind.

Ken

He actually says down to 200mm (at 7:40).

Considering a T-4 wheel starts at 200mm... it seems a bit of a conflict?  I think on chisels etc. with wider bevels it might matter... but on knives, the hollow is pretty slight, IMO.  Lately, I've been using the Tormek (T-4 at around 198mm) to just set the bevel, finishing them on bench stones, and if I use a coarse stone, I'll see scratches across the entire bevel under magnification, after just a little sharpening.  (By comparison, with a fine stone, they're mainly at the top and bottom of the bevel).  So the hollow is there, but I'm not sure how to practically test to see an actual influence?... although I'm pretty happy with the results at this point... if anything, my theory is, the hollow just behind the bevel could improve performance... (but haven't made any actual direct comparison or testing).

[Ken S]

CB,
You are correct about the 200mm.  (Oops......)

I have thought about combining the 250 and 200 mm wheels during sharpening. I have not formulated any conclusions. I'm basically a chisel sharpener.

Ken

[RichColvin]

When I sharpen on grindstones that are 180-200 mm on my T-2000, I use them on turning tools, both wood turning and metal, and on my pocket knives.  I find that the small amount of concavity in the grind is not a real issue.  What is more of an issue is not sharpening often enough.


Rich

[John S]

Bump.  I'm still looking for a tired SG250 if anyone is willing to sell.

John

[RichColvin]

John,


Ping me in about 5 yrs.  Retiring in 3.5, so should have my new one used up by then.


Kind regards,
Rich

[John S]

Rich,

I think we live close to each other.  Do you only sharpen woodworking tools? I am learning knife sharpening.  My latest quest is to learn serrated knives.  If you have tons of experience how might I arrange a lesson from you?

John

[John S]

I have acquired a SG200 wheel. I am no longer in need if a wheel for my T4.

Thank you,
John