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Hello everyone, I have the following question.

I have a Tormek SJ-250 Japanese water stone (4000 grit) and Tormek - PA70 polishing paste (3000 grit, if I'm not mistaken). Does it make sense to use a coarser polishing paste after using the water stone with 4000 grit?

My take on this is "Yes, it does". The SJ leaves a burr that you'll have to remove, and the PA-70 does a really good job of it. In my experience it will not unpolish the edge left by the SJ. Plus you probably want to hone at +1/+2 dps compared to your grinding angle, so that won't show much.

That, exactly. And IMO the result after going DF -> DE -> SJ is underwhelming. The diamonds leave a rather sparse scratch pattern that's hard to get rid of entirely.

So if you really want to start with the DF, i would recommend DF->SG ungraded -> SG graded fine -> SJ.

I would second what Ken said, and maybe put it in a slightly different light : unless constrained by space or portability restrictions, go for the T8 : you'll get more mileage out of a stone (overall and in between truing sessions), grind profiles will be closer to a flat grind, and the wheel is 25% wider, resulting in more consistent results (less dishing) on wide blades.

Wow, this is so nice !!!!

For those of you who could be interested in this system, there is a baseplate variant called Clickfinity ReFined that allows for containers that click in place and won't budge without using magnets. Just don't print in PLA because it will creep. Thank you for the models !

I've never ground plane blades, but wouldn't the square trick help as well ?

That is, tracing a line on the top of the wheel, perpendicular to the side, and check that the plane blade is on the line and stays on it when moving the jig ? As shown by Wolfgang in this video....

As one person put it, in academia and many other careers the only purpose your body serves is to get your head to the next meeting.

If only you were right. Post-COVID zoom meetings have managed the feat to make this head-carrying thing totally optional...

But I digress, I'm impressed by the extent and quality of @andicugino's workmanship.

It might be unnecessary, but I would also smooth the concavity with a dremel on low speed to make sure it won't catch and chip again.

As John and Rick said, the stone will work just fine.

The ultimate advantage : due do the differences in heights and materials of the stones, what's left of your knife plays "Mary had a little lamb" when banging on the Sharpnado !

It would be easy to print such images then use the paper print-out as a template.

I used the tools themselves as templates for shaping ShadowFoam. It allows for cutting at different depths to match the depth of the tool/jig.

John, this is such an enlightening post !

I didn't know about Mohs hardness before reading it, and I've spent yesterday night reading/watching stuff related to it.

A quick newbie question though : if I understand the principle correctly, wouldn't just the MOHS hardness level 9 tester be sufficient to choose between CBN/Diamond or SG ? If I'm not mistaken, level 9 means "scratched by Al2O3 but not by topaz". So in short : before sharpening, get your corundum tester, if it scratches then use SG, if not use CBN/diamond ?

Better yet : could we not try and scratch the surface of the knife with the edge of the SG wheel, observe, and choose the wheel accordingly ? It seems the SG is precisely Al2O3...

Ooooh, damn, reviving a 10+ years old post as your first post here, along with a commercial link. Congratulations.

As a tongue in cheek answer though, there are plenty of posts on the finish given by the leather wheel with various compounds (diamond, chromium, standard Tormek). Also on felt wheels, paper wheels and such... I'm not sure carving tools require more than the finish given by the standard PA-70 which can be pretty fine.

Not much sticks to delrin (Polyoxymethylene), so if one were to try to glue it in place, it would need to be deeply grooved in an angular or lengthwise a way such that the dried glue would act as keys, locking the sleeve in place.  The circular grooves in the photo the OP showed may not be adequate. 

Rick

This is why I recommended PUR glue : it expands when setting and is waterproof. So it should work on a crosshatched/crisscrossed/rough surface, even made of POM.

Nice work !

I would 3D-print a piece of PETG with cross-hatched outer surface, as I wouldn't know where to procure POM with the proper dimensions, and don't know if I'd drill it dead center.


I'd use PUR glue.

Welcome to the forum, Malmosyd. We have always had some confusion with angle terminology. I think the clearest way to describe knife bevels is "degrees per side", sometimes abbreviated DPS).

As for tip grinding with the T1 (and T2, which uses the same knife jig), I understand the reservations, since the design does not allow raising the knife to sharpen the tip of the blade. Tormek has always preached the necessity of raising the knife to sharpen the tip of the blade WHEN USING THE TRADITIONAL SVM AND KJ KNIFE JIGS. However, I can not believe that Tormek engineers just ignored this in designing the T2 and T1. No mention is made of this in any of the online classes.
(I hope this will be addressed in detail in a future online class.)

Of the several critical posts about this, I do not recall any from T2 or T1 owners who have actually experienced this problem.

Ken

I am not rich enough (including in kitchen real estate) to buy a T1 in addition to the T8s. Yet I fail to see how owning one (nor Tormek engineers thinking real hard about this) would create a singularity in Euclidian mathematics to the point that a constant angle would give the same results as a variable angle method on every knife.

Widening of the bevel at the tip is a known concern with all constant angle sharpeners, whether belt-,rod- or wheel-based. I own a Global GS-3 where this phenomenon is quite clear, although for many kitchen knives the effect will be offset by the thinning of the knife at the tip. The T8 gives control over this, not the T1/T2.