using SJ-250 after initial 200/1000 grind via SG-250

[eckorsberg]

First off I am new tormek T8 user and new to this forum and thus apologize in advance for any etiquette violations.

I wonder if the tormek SJ-250 Japanese water stone is worth it.  One concern I have is that with use, the standard SG-250 will decrease in diameter and will become smaller than the presumably lessor used SJ-250.  Thus when we sharpen on Sg-250 at 200 then 1000 grit and then change wheel to the new SJ-250, the diameter will likely be different enough that we are no longer simply refining the previous edge but will in fact have to reshape the edge according to the new 250 mm diameter SJ-250 wheel.  This seems to imply we might was well just do all the grinding on the SJ-250 which is clearly not the intended use.

Am I overthinking this issue?  But it seems to me regardless how we use the AngleMaster, in the limit the metal edge (chisel or knife) will have a radius according to the SG-250 wheel (lets assume 200 mm).  Then when we attempt to finish the honing with the 250 mm SJ-250 then the chisel front and back edges will touch the stone but the center will have a small gap.  We would have to continue grinding using the SJ-250 to completely hone to the new 250 mm circumference.

[cbwx34]

First off I am new tormek T8 user and new to this forum and thus apologize in advance for any etiquette violations.

I wonder if the tormek SJ-250 Japanese water stone is worth it.  One concern I have is that with use, the standard SG-250 will decrease in diameter and will become smaller than the presumably lessor used SJ-250.  Thus when we sharpen on Sg-250 at 200 then 1000 grit and then change wheel to the new SJ-250, the diameter will likely be different enough that we are no longer simply refining the previous edge but will in fact have to reshape the edge according to the new 250 mm diameter SJ-250 wheel.  This seems to imply we might was well just do all the grinding on the SJ-250 which is clearly not the intended use.

Am I overthinking this issue?  But it seems to me regardless how we use the AngleMaster, in the limit the metal edge (chisel or knife) will have a radius according to the SG-250 wheel (lets assume 200 mm).  Then when we attempt to finish the honing with the 250 mm SJ-250 then the chisel front and back edges will touch the stone but the center will have a small gap.  We would have to continue grinding using the SJ-250 to completely hone to the new 250 mm circumference.

You're right, although it would probably be a while before you had a real problem.  I think it also depends on if you're trying to polish the entire bevel, or just refine the cutting edge.  One would require what you said, the other just a simple angle adjustment.

You might find this thread interesting:  "Polishing Angle Calc"