Chromium oxide bars, or not?

[D_W]

He did at least attempt an answer. I retired defeated.

If it's clarity and brevity and a tangible conclusion that you want, you'll never get it

 

[matthewwh]

It's just an extension of the answer you would give if someone asked you "why do you sharpen your tools?"

A sharper edge requires less effort / pressure to push it through the wood, the less pressure you need the more control you have. It isn't necessary all the time, but in situations where you need a lot of control or are working in very hard timbers, having a very sharp edge really does help.

Once you have availed yourself of the kit and techniques to achieve really sharp edges you start doing it all the time because it's not really any extra effort.

Then you start finding the limits of different steel compositions and heat treatments, and start to get just a little bit geeky about the whole thing.

Before you know it you're on here discussing the shape of chromium oxide particles with people on the other side of the planet.

 

[D_W]

I guess the follow-on question then is what situations in most work really require it. I'm not heckling, I shave every morning with a straight razor and have been so far down this road that my bench has in it tenth micron diamonds in it and .09 micron iron oxide from kremer pigments.

but I found that the ideal situation for razors is actually a genuine linen and broken in horse butt (cordovan is fine, and works sooner than horse butt, but the ultimate result after broken in for both is the same), right off of a stone. The edge cuts hair just as easily, but has less bite on skin, and so all of my pigments and bits and bobs sit.

I spent the weekend dimensioning wood, and capped it off in the evening sawing 4/4 out of 8/4 (when your wood stock gets desperate, you do this kind of thing - I needed 1.75" rails for a wide kitchen cabinet, but I have no 4/4 stock remaining long enough), and then finishing the remnants off after thicknessing them (by hand of course).

I used a cheap smiths oilstone (but one that they call hard, though it's not nearly as fine as a true hard) and I chased off the wire edge with a cheap piece of jasper. The two cost $25 together.

This wood would cause a beginner fits to plane. The equalizer was the cap iron. I still have all of the expensive sharpening stuff, but when the sweat starts, simple is the order. I use the same setup for paring and carving chisels, with the exception of using slips when necessary, except I usually use a better stone in place of the smiths, I just wanted to try the bargain stone for curiosity. It's usually a washita.

https://s13.postimg.org/6f3n5bpxj/IMG_2 ... 2520_1.jpg

https://s16.postimg.org/v9xwg7ktx/IMG_2 ... 7604_1.jpg

And the level of finish off of an 11" board that I also resawed by hand (from the cheap oilstone) - sorry about the quality of the picture - I think the phones have software in them that prevents them from wanting to see reflection or glare on anything and it makes it very hard to see the reflection and focus on the wood as we would with naked eyes:

https://s15.postimg.org/51mhte7zf/IMG_2 ... 5780_1.jpg

(doing this work would've been a holy terror in my formative days where I refused to use anything that wasn't at least shapton 15k pro sharpened, and I didn't know how to set a cap iron)

 

[No skills]

I think everybody has their own trigger point for diminishing returns no matter what the subject or task.

I find the odd thread like this interesting reading (from a barbaric wood murderers perspective), I have a bar of green possibly non-descript polishing compound being delivered this week - a first for me but boring humdrum for others.

 

[D_W]

I have a bar of green possibly non-descript polishing compound being delivered this week - a first for me but boring humdrum for others.

We've all gotta see it for ourselves and in person. Me included!

 

[No skills]

Yes indeed. Human nature.

8)

 

[Biliphuster]

Hmm. If it's not removing metal then it's doing something very clever indeed, probably at the atomic or subatomic level by rearranging the atoms of the blade without removing them. I think a Physics Nobel prize is in the works!

Some polishing compounds work by chemical action, for example Cerium oxide is commonly used to polish glass and works by partially dissolving the surface of the glass which will smooth out ridges and bumps.. Colloidal silica is another common polishing media that works at least partly chemically.

I agree the Chromium oxide is probably only acting as an abrasive but this is not true for all polishing compounds.

 

[matthewwh]

There are several factors involved in hand planing other than just having a sharp iron, on reversing grain a steep effective pitch, achieved by whatever means, is at least as significant a factor as edge condition. This makes it a poor example of a situation where sharpness itself is critical.

Paring endgrain with a chisel is the traditional example of a situation where a sharper edge is desirable, indeed the ability to pare softwood endgrain cleanly without separating the fibres is often used as an imperfect measure or means of comparing sharpness.

 

[profchris]

Hmm. If it's not removing metal then it's doing something very clever indeed, probably at the atomic or subatomic level by rearranging the atoms of the blade without removing them. I think a Physics Nobel prize is in the works!

Some polishing compounds work by chemical action, for example Cerium oxide is commonly used to polish glass and works by partially dissolving the surface of the glass which will smooth out ridges and bumps.. Colloidal silica is another common polishing media that works at least partly chemically.

I agree the Chromium oxide is probably only acting as an abrasive but this is not true for all polishing compounds.

I had to look up colloidal silica, which seems to work in part by reacting with the thing being polished to form a compound which is easily rubbed off. But that's removing material, as is the glass example, though not by abrasion as you say.

I couldn't think of any way to polish without removing material.

 

[jlawford]

Veritas green honing compound works great. 1200 grit diamond stone straight to a leather strop with compound rubbed on. You can see carbon from the steel and fine reflective flecks of burr in the leather. Diamond gets the edge, hinting polishes and refines.

 

[D_W]

There are several factors involved in hand planing other than just having a sharp iron, on reversing grain a steep effective pitch, achieved by whatever means, is at least as significant a factor as edge condition. This makes it a poor example of a situation where sharpness itself is critical.

that's correct, though certainly more important than just a steep effective pitch is being able to work it efficiently. Using a cap iron will do this efficiently. Anything else will take significantly longer and much more effort (because a lot of the work is rough work in quartered wood).

Paring endgrain with a chisel is the traditional example of a situation where a sharper edge is desirable, indeed the ability to pare softwood endgrain cleanly without separating the fibres is often used as an imperfect measure or means of comparing sharpness.

This is always given as an example, but the times we pare a show surface are fairly rare. Carving would be a good substitution. The sharpness needed to carve cleanly is pretty common in any finishing regimen, though. Autosol, compound, 3 micron stones, hard arkansas slips and a strop, etc. Most of the stuff that we pare, like tenon shoulders, is a bit of an exercise in force (often done faster malleting, anyway).

I guess what I'm getting at is when we start to sweat, the wood show stuff falls by the wayside and what shows merit appears pretty quickly. For 80-90% of the planing, that's getting clearance quickly, and for most of the rest of it, it's uniformity with decent sharpness (but getting there quickly).

 

[Andy Kev.]

Genuine question: I've read that if you sharpen up into the higher thousands, the edge you achieve is good for a few passes of the plane then it goes into a slow decline during which it will continue to cut perfectly well. That seems fairly logical and so you rehone when experience tells you you need to or when you are finishing a piece of wood and you want the lovely surface that a newly sharpened blade gives (well that's my modus operandii, at least). So my question is: having identified the need or wish to use various compounds to achieve a super-duper sharp edge at the higher end of what is achievable, isn't the key question about how long that edge is retained while planing a particular type of wood (edge retention must vary from species to species)?

Therefore if we have sharpened at, say 8,000, then used whatever oxide compound before working on e.g. cherry, don't we need a table where we can look up cherry against sharpening regime in order to find out that we can manage 12 passes before needing to rehone? Otherwise we have surely done no more than delay the slight dulling of the edge to what we could call normal working sharpness.

Or am I just theorising wildly?

 

[AJB Temple]

The Japanese knife aficionados use a diamond stropping solution that can be bought in a range of sizes down to 0.1 micron I believe. I was given some 0.3 micron diamond solution by a US friend (just because I expressed curiosity) but have been unable to ascertain any difference in edge sharpness as compared with my normal stropping method which uses a German made waxy stropping paste, on a leather strop. (Balsa is often used by the diamond solution people).

I also have a 12000 water stone, (again just for interest) but going beyond around 8000 for a kitchen knife yields no benefit in my experience even for very fine sashimi knives. The razor guys may well have an entirely different perspective. I have never tried an open razor: too scared!

 

[Trafalgar]

.05 micron optical polishing powders, not sure if there's anything finer, if it's good enough (quality control, etc., etc.) for a $3MM electron microscope it'll work on $30 chisel:

https://www.emsdiasum.com/microscopy/pr ... plies.aspx

There's nothing more mission critical than polishing glass on very expensive optical devices.

Scroll down at the link; lots of interesting products - diamond pastes, sprays, other slurries in a huge variety of grit sizes.

 

[woodpig]

I doubt there are any products made specifically for honing. More likely they are just polishing compounds.

https://www.menzerna.com/products/solid ... steel/333/

http://www.thepolishingshop.co.uk/acata ... ar-p1.html

 

[Trafalgar]

If it's polish one is after, with very little cutting of metal (surely a little will take place no matter what), it seems to me one would find the absolute finest grit product available, of very high quality grade and without contamination, and be done with it. If it'll polish glass then it will put a shine on tool steel.

Why beat around the bush? What's the point in 'trialling' products that are coarser by multiples of 10 if not 100? Otherwise, and if you're of the type, it will be a constant nag on your conscience. What are you leaving on the table? It would be like a fly picking its own wings off - self flagellation.

 

[D_W]

I doubt there are any products made specifically for honing. More likely they are just polishing compounds.

https://www.menzerna.com/products/solid ... steel/333/

http://www.thepolishingshop.co.uk/acata ... ar-p1.html

There are progressive razor pastes made for honing razors without stones (by dovo). I don't think they'd be that practical, though. Four of the progression are abrasive, but only the finest is as fine as the things being discussed here.

 

[Cheshirechappie]

Out of passing interest, anybody know the particle size of Jeweller's Rouge?

I know it's basically haematite - an oxide of iron - sometimes supplied as a powder, sometimes mixed with wax or grease in a stick to apply to polishing mops, and I know it's used as a final polishing compound on softer metals, leaving a high shine. However, a brief rummage in the interwebs didn't give me a grit size.

I've had a block of it for years - bought it from Axminster's. It leaves a lovely polish on a cutting iron bevel when used on a leather strop, but I've never really been convinced that it sharpens an edge better than a polishing stone does. It doesn't seem to do any harm, but apart from a shiny bevel, I'm not really convinced it does much good either. I'm more inclined to used a bare strop (or palm of hand, or scrap of wood, or whatever else happens to be handy) to chase off the wire edge from a fine India, or use the edge from a slate polishing stone without stropping when I want maximum sharpness.

 

[matthewwh]

I believe it's similar in size to chromox and again ball shaped particles but not as hard.

I don't know if this adds anything to the debate, but 9 times out of 10 I use a strop to rejuvenate an edge that just beginning to go off instead of honing it. Obviously there comes a point where stropping isn't enough or is taking too long and it's time to re-polish the secondary bevel, but for me the main function of a strop is as a lazy way to extend the working life of an edge between proper sharpenings.

Stropping on the palm of your hand works if you don't have anything else, but it's can come at a price. I now have an irritating persistent lump of hard skin on my left hand that I believe is caused by a deeply embedded metal splinter from doing just that. It's hardly life threatening but I wouldn't recommend it.

 

[D_W]

Stropping on the palm of your hand works if you don't have anything else, but it's can come at a price. I now have an irritating persistent lump of hard skin on my left hand that I believe is caused by a deeply embedded metal splinter from doing just that. It's hardly life threatening but I wouldn't recommend it.

It leads to a filthy palm if you do it enough times in a session, too. Eventually the filth ends up on wood.