Great article on honing / stropping

[grepper]

With mention of the Tormek honing compound.  The results may surprise you.

http://www3.telus.net/BrentBeach/Sharpen/Stropping.html

[mike40]

I found this excellent article very interesting Grepper. Thanks for posting it. The author's conclusion seems to somewhat endorse Tormek diamond paste and the strop wheel method. The edges on my first chisel and plane iron seemed to benefit quite a bit from stropping on the leather wheel. I have had mixed results with stropping by hand on leather, but I did get better at it with time. I learned to be a lot more careful than when I first started because I ruined so many edges with bad technique. I find it interesting that one guy didn't like the Tormek diamond paste and was using the Lee valley green which was discussed in the article. I can't remember where I read that, but it was recently. Maybe a Tormek review, not sure.

[grepper]

I found that very interesting too, Mike.

The thing about the Tormek compound is that it is very fine, and pretty consistent in size, 1 – 3 microns, where other crayons have much greater variance in abrasive  particle size.  Considering that abrasives work at the largest grit size in their formulation, the Tormek honing compound is honing at about 8,000 grit.

It's interesting that even at 3 microns, under a 200X microscope, scratching, albeit very small,  is still apparent.   Practically, for our purposes, that's pretty meaningless, but I find it interesting nonetheless.  I'm getting a much better understanding of how  abrasive coarseness effects steel.

Mark

[Jeff Farris]

Particularly interesting about Tormek compound is that it contains nearly equal parts 1, 2, and 3 micron abrasive. When the 3 micron particles break down, the 2 micron particles take over, and when the 2 micron particles break down, the 1 micron particles take over. If you experiment with different compounds (I have...quite a bit) you'll find other compounds that will leave a surface as polished as Tormek compound, and you'll find some that cut as fast as Tormek compound, but you won't find the combination of fast cut and fine finish.

[Rob]

Test post

[grepper]

Well, isn't that just the coolest thing!

I've noticed that  when you first apply compound that it fees more "cutty", i.e., more resistance.  Then after honing for awhile, it's much smoother.  I had never really considered that what was actually happening was abrasive particulate breakdown.  I thought it was just getting worn away as it seems to end up on the bench.

Nor had I considered that could actually be advantageous.  Cutting to polishing in one squirt of compound!

My, you are a veritable cornucopia of useful information Jeff.    Thanks.

[Rob]

Are we reading the same article?

The conclusion of this "very objective and scientific approach" is that the experimenter REFUTES stropping as a useful technique after sharpening. He says it changes both the edge geometry and the steel integrity. Here's a quote from his conclusion
---__-------------------------
The second case often cited is stropping of a freshly honed tool. That is, as the last step of sharpening people strop the tool. If you use the abrasives and the jig I do, honing produces exactly the edge profile you want and steel condition you want. Further abrasion, particularly freehand abrasion, can only begin the wear process! You would notice no benefit. In fact, you would notice reduced edge sharpness and durability.
--------------------------------

He goes on to discuss any opinion to the contrary (since his tests prove otherwise) is either "magic thinking" or an accidental improvement in sharpness due to correcting poor original grinding (which he calls honing). So boys, either I'm misreading this or Mr scientist is rejecting stropping of plane blades and chisels??

[Rob]

And incidentally, I might be misreading it cos I'm in the emergency room of hospital doing this on an iPhone!!

[Rob]

Here's a quote of his final conclusion:

------------------

Conclusions

What conclusions should you draw from these tests?
If you are using 3M microfinishing abrasives you should not strop using any of these compounds on a maple board.
If you are using some other abrasive or blade holding method, and if stropping is improving the sharpness of your blades, then your previous honing step is producing a bad profile. You should investigate other honing techniques - in particular, the techniques discussed in these pages.

-------------------------------------------

He's trying to demystify stropping isn't he?

[grepper]

I agree Rob.  I found it confusing too.  The key to understanding what he is sayilng is:

"...in all cases stropping left a worse edge than I was getting after the 0.5 micron 3M abrasive sheet.

So, he's honing to something like 30K-60K grit, with 3M Micron abrasive film, and then comparing that to stropping with compound.

Like I mentioned, "Practically, for our purposes, that's pretty meaningless, but I find it interesting nonetheless."

It does howver give some perspective on exactly what is happing when you strop with compound, and how that compares to fine abrasives.

BTW, hope everything goes well!  Sitting in the ER ain't no fun!

[Rob]

Last test at 10:30 tonight. If all well I go home. Chest pain this morning while cutting cherry bowl blanks from a tree I was given yesterday

Personally I think it's a fuss over nothing. Been here all blinking day while my blanks need waxing!!

Bored bored bored!!

[grepper]

Here's some more stuff you can read whilst being bored!

http://www3.telus.net/BrentBeach/Sharpen/sitemap.html

He's into planer blades.  I'll bet the blades he sharpens are the sharpest you would ever use.

He hand sharpens at 15,5,0.5 micron abrasives on glass.

A lot of interesting info on his site.  Might help reduce bordom for an hour or two. 

[Rob]

Cheers old son :-)

[Rob]

Blimey......and I thought we (on this forum) were anal about sharpening. This guys in the stratosphere!!

[Ken S]

Thanks for posting the article, grepper.  I printed it out and found it interesting.  I believe the author is heading in the right direction, although I would not consider the article definitive.

I liked the idea of using the jig for consistency.

I was less impressed that he used several types of blades to test the different compounds.  He probably did not want to end up with an unusably short blade at the end.  I understand this.  However, adding blade variables does not help substantiate the research.

I know nothing about the author's background or credentials.  I use both terms because someone like our own Jeff, while he might not have a PhD in forestry from Yale, does have a very extensive amount of field experience.  I appreciate both the academic rigor of Dr. R Bruce Hoadley (author of Understanding Wood) and the "in the trenches" experience Jeff has developed over the years.  We need both.

I would be curious to know how fine diamond paste would compare.  I would also like to know more about the effect of using 90 grit valve grinding compound.

What about the effect of abrasives breaking down with use into finer grits?

Jeff exaggerates the effect of the Tormek compound.  The US Forestry Service, after a multimillion dollar ten year study, that the use of the Tormek compound and leather wheel was only 94.327% as effective as an 8000 grit flat water stone. (Just kidding, Jeff.....) Seriously, I think Jeff's comment deserves some serious consideration.  Any process which can offer results so close to a longer process in a fraction of the time warrants thought.  In the machine trades, operations are not done for perfection ("dead nuts" perfect).  Well established standards of tolerance for different applications are used.  While 95% at one fifth the labor cost might not suffice for the most rigorous laboratory standards, it would probably exceed the requirements for almost all other work. 

One question, Jeff:  How long would you guess it took you to reach a level of high proficiency with the leather honing wheel? 

Thanks,

Ken