What's the difference between a smoothing plane and a polishing plane?

[Phil Harding]

I've seen polishing planes advertised in the Japan Woodworker catalog and was intrigued by the name. The name implies to me that this plane it will leave a smoother (e.g. polished) surface than I would normally get from a well set smoothing plane. So, while at the Milwaukee Woodworking Show last weekend I bought a small Mujingfang Polishing Plane from the Woodline booth. I've played with the plane a little but want to hone the edge before I try to compare it's performance to my LN #3 smoother.

BTW, the plane is advertised has having an A2 blade, but this blade is much harder than any A2 blade that I have from LN or LV. It's so hard that I'm having trouble flattening the back and honing the edge on ceramic waterstones. I'm getting there but it's taking much more time than I had expected.

So, my question - what makes this a "polishing" plane?

Thanks,

Phil

[David Weaver]

A diamond hone will bring the muji irons into order.

I don't know who got the idea they were A2, but they definitely are not. I've never seen a Muji plane with an A2 iron. The iron will feel "slick" or "gummy" on ceramic stones and clog the surface of them, generally, at least on the soakless ones. You can still use those stones to finish it off after you get it flat, but it's likely that you will need something with diamonds to get it properly flat unless you can tolerate hours of flattening. The diamond hone will come in handy later sharpening it.

if you don't have one already, the cheapest good option I know of is the duosharp on amazon. I got one with a base to give to buddy in kagawa for $60 a couple of weeks ago.

There are cheaper hones that are good, too, but they are not quite as consistent in flatness, and ultimately not that much cheaper - maybe 15 bucks, and less than that if shipping is free on the duosharp.

The iron really steep on the plane you're talking about?

Polishing is just one step further after smoothing. Smoothing means a lot of different things to different people. For some, it's going ultra fine after a machine tool, and for others, it's just removing marks or scallops left by coarser planes. "polishing" doesn't necessarily imply that a surface will be shinier, sharpness, the subject wood being planed, and the angle of attack of the plane ultimately determines that, but it does imply that you are not going to improve the surface further.

If that is one of the steep ironed mujis, you will very likely not be able to create appreciable tearout on anything with it - a handy little plane to have around where normal smoothing with a common pitch plane leaves tearout.

I think JWW might call them polishing planes, but i have seen other japanese sources use the term "finishing" plane after a smoothing plane. As just a fan of the japanese planes and not so excited about tradition (not against it, just indifferent about talking to wood and things like that), i couldn't tell you an exact definition for "finishing plane", just that I see the value in a second more finely set smoother sometimes, especially on a fine-finish surface that will not be taking a heavy dose of lacquer or shellac.

[Jim Koepke]

Phil,

You may be the one who will have to supply the answer to your own question.

Didn't see any mention of the A2 blades. Did see one reference to the blade being AA quality. Having not look at each one, it may have missed. There was mention of some of the blades being hardened to Rc66. That would be hard to hone.

From the Japan Woodworker web site, it looks like the main difference is the polishing planes have narrower blades than the smoothing planes.
The site also says the polishing planes are used for smaller areas.

jtk

[Johnny Kleso]

IMHO Diamonds bench stones are not the best thing for bringing out the sharpness of a blade.. Stropping is and proper prep to stropping is..

I never hard of a polishing plane but sounds like it would be a scraper of some sorts..

[john brenton]

David has said that the Mofochingchongs have HSS irons.

[David Weaver]

Johnny - the issue with muji planes is flattening the iron, which is what the diamond is needed for, not necessarily for the bevel side.

Flattening HSS is a nuisance on a ceramic stone, but the bevel can be sharpened on one and a reasonably good finish on the back can be gotten on them after the back has been flattened on something diamond.

Once everything is done, HSS is a nice target for a powered hone with a fine stropping compound on it, and it will subjectively be as sharp as anything else.

The high angle muji planes are obvious targets for HSS for two reasons:
1) they are high angle, so you can still have a strong final bevel (like 35 degrees) and still have a lot of relief angle. HSS isn't intended for 25 degree hollow hones, for certain.
2) carbon steel irons dull fast at 60+ degrees. HSS irons stay sharp for a lot lot longer than carbon steel at angles like that.

[David Weaver]

David has said that the Mofochingchongs have HSS irons.

Yeah, I would guess the hardness low 60s, like an HSS turning tool. They're not super glass hard like some of the japanese tools, but they are plenty hard and wear a really long time, longer than the japanese tools do, but a totally different animal. High carbon japanese tools work well at shallow angles, so it's an apples to oranges thing.

All of this talk lately really has me jonesing for another japanese plane. Gonna have to put more stuff in the classifieds to build up the kitty so's the wife doesn't see the transactions in the bank account.

[john brenton]

So what's your recommendation? Water stones?

I just finally found a use for my 220 and 1000 stones. I picked up the HSS turning chisels from HF to replace my older carbon steel chisels. The stones make quick work.


Yeah, I would guess the hardness low 60s, like an HSS turning tool. They're not super glass hard like some of the japanese tools, but they are plenty hard and wear a really long time, longer than the japanese tools do, but a totally different animal. High carbon japanese tools work well at shallow angles, so it's an apples to oranges thing.

All of this talk lately really has me jonesing for another japanese plane. Gonna have to put more stuff in the classifieds to build up the kitty so's the wife doesn't see the transactions in the bank account.

[David Weaver]

I haven't used an aluminum oxide clay-based waterstone on HSS, so I can't really comment whether not they can handle HSS. I know stu can. HF's HSS chisels are likely on the soft side. I have a "benjamin's best" gouge and it definitely doesn't last as long as the crown and sorby tools, though it's certainly usable.

I have been using a 1000 grit diamond hone to cut a microbevel on my mujis (or more accurately run off the wear on the bevel ), and then a shapton 15k to put a tiny third bevel. I lap the back on the shapton, too, which is a bear when you're first getting the scratches from the prior step, but with as little wear as it gets through use, it's tolerable.

There is still a bit of a wire edge after the 15k stone, I think. I whiz the iron quickly across a chrome oxide leather disc on a disc sander (which moves at an extremely high rate of speed and can burn an iron, but HSS it'll just burn your fingers instead when you feel it).

There are stones now that cut hss, but i don't like soaking stones. I'd rather flip the switch on a sander and take care of business in 15 seconds. The same disc could also lap the back of the iron if needed a lot more easily than a shapton can.

Loose diamonds would also be an option, but I just don't like the finish diamonds leave on an edge, even sub micron. They will make anything equally sharp, though.

(it's definitely a lot easier to work the bevel on a turning gouge than the back of a plane iron, i do the same thing with my turning tools - give them a few swipes after a grinder)

[Phil Harding]

David, I got the idea that the iron in the Mujingfang polishing plane is made from A2 steel from The Japan Woodworker catalog. I did finally use a extra coarse diamond stone to get the back flat. From the extra coarse I went to a coarse diamond stone and then through 220, 1000, and 8000 Shapton waterstones. I've never had to put this much work into any other blade I have. I still have to hone the bevel and I'll do that after I recover from the effort of flattening the back. The iron is step at about 60 degrees.

Thanks,

Phil

[Brian Kent]

The difference between the smooth plane and polish plane is the steep angle - about 62° on the polish plane. They are absolutely fantastic on strange grain, and the sharpened irons stay sharp for a really long time - and I use it on extremely hard woods. They really did well on a smooth plane test a few years ago but I don't have time to look for the article until late tonight.

[David Weaver]

Phil, i've seen that stock language before. Someone must've made a bad translation at one point in the past, and now it shows up in their listings everywhere.

The only thing I can say about it is the listing is wrong and the error is in your benefit when you find out what it really is. You'll be very pleased with its ability to hold an edge, especially if you ever use a carbon steel iron at that bevel angle.

[David Keller NC]

Personally speaking, my opinion is that a polishing plane and a smoothing plane is a matter of semantics - there is no difference. I most frequently see the reference in British and European literature and by craftsmen trained in those traditions. For example, I don't know too many American craftsmen that would refer to wood as "timber" unless they're referring to standing trees or possibly the extra-large pieces intended for a timber-frame structure, but many British websites do refer to "timber" in the same way we would use the terms "lumber".

[Johnny Kleso]

Johnny - the issue with muji planes is flattening the iron, which is what the diamond is needed for, not necessarily for the bevel side.

Flattening HSS is a nuisance on a ceramic stone, but the bevel can be sharpened on one and a reasonably good finish on the back can be gotten on them after the back has been flattened on something diamond.

Once everything is done, HSS is a nice target for a powered hone with a fine stropping compound on it, and it will subjectively be as sharp as anything else.

The high angle muji planes are obvious targets for HSS for two reasons:
1) they are high angle, so you can still have a strong final bevel (like 35 degrees) and still have a lot of relief angle. HSS isn't intended for 25 degree hollow hones, for certain.
2) carbon steel irons dull fast at 60+ degrees. HSS irons stay sharp for a lot lot longer than carbon steel at angles like that.

Hi David,
For a few years I was a foreman of a diamond tool company and diamonds are too hard for hard steel.. what works better is a friable grit that breaks down and exposes new cutting edges.. For flattening scarp sharp would work as you only need to do this one time.. Diamonds work just very expensive for same a few minutes..

[David Weaver]

Diamonds are not expensive, and for carbon tool steel, they may not be necessary, but nothing cuts high speed steel faster than diamonds. The notion that they are too hard for steel is outdated or misplaced when talking about abrading by hand, there is no abrasive that is "too hard" for something else when you're attempting to abrade material and not polish.

It costs about $15 for 20 carats of diamonds, maybe less. I would guesstimate that to be enough abrasive to do 50 irons if used properly. I haven't finished a 20 carat packet on 30 irons and many of them were badly pitted, several were HSS, which was so much faster than silicon carbide that I would say the savings was at least 15 or 20 minutes.

That statement by your foreman may be outdated or it may be more appropriate for very large volume work where a beancounter wants to shave a few cents on each job. Quite possibly it's also more appropriate for grinders, but we are talking about working by hand. The cost of manmade and industrial grade natural diamonds has come down *a lot*, especially at the retail level. I would go through far more 3x paper than $15 worth in those irons, i've been there and done it. I have also used silicon carbide loose grit with a lubricant as well as aluminum oxide loose grit. They would be appropriate at high speed, but they fracture too quickly when lapping with slow speed and high pressure (by hand), and create an unnecessarily large amount of swarf that is too fine to be useful when you really need to grind.

What you want for hand lapping is something that both:
1) does not fracture easily
2) stays sharp

The diamonds cut like fresh al-ox grit or like fresh 3x paper, but they do not slow down and break down quickly - they continue cutting at that speed. They do not create a large amount of swarf (the swarf is all metal instead of a lot of grit) that needs to be removed in the middle of the process and importantly they generally maintain their initial size to continue cutting fast.

A 2 pound bag of al-ox grit cost me ten dollars. I'll never use it all. Figure i probably use 10 or 15 cents of it if I flatten a high speed steel iron. At the same time, I will use probably less than 50 cents of diamonds, and at the same time will be on to the medium stone 15 or 20 minutes faster. I'm not willing to trade sweat work at 2 cents a minute.

[David Weaver]

Just looked it up, 100 carats of 80/100 grit diamond is now $22. Unless someone here sells tuned tools, if they use a pinch each time they do an iron, they will never use it all. It is money well spent, and possibly cheaper than other grits in the end, especially considering folks here aren't going to get those other grits 50 or 100 pounds at a time, which is where they're really cheap.

edit: I apologize if I come off a little bit too direct when this is the topic. Only because i screwed around with every method known to man, including power flattneing (which I never found to be matched well with hand flattening - though I haven't tried the WS3k, I think running scads of pitted irons out on it would create quite a large paper expense).

I did bunches of irons and chisels on norton 3x, which works well, but it wears smooth and you never feel like you got your money's worth with it when you go through more than a full sheet on a badly pitted iron. Plus, you have to screw around with adhesive.

Tried stones, never liked them. The ones coarse and hard enough to do the job are hard to flatten.

Tried al-ox and SiC, and both of those worked ok, but tons of swarf and they went fine too fast. Adding more grit just makes more and more swarf and makes it hard to see progress. The other obnoxious thing about them is that while the grit went finer, if you managed to run into some fresh grit on the corner of the plate right before you were done, you had a surface that was "fairly fine" but with a couple of big scratches on it, so if you wanted to get those out, you still couldn't go to a finer stone than you can the diamonds (which leave all big scratches)

Mild steel plate with a continuous surface - no relief cuts - (could be free, but at most about $25) mounted on a block of wood and a home-made (free) iron holder with just a sprinkle of diamonds and WD40 makes for a very easy to use and very fast and deep cutting abrader. The swarf is only the iron, basically, because the diamonds quickly settle into the steel plate and stick. A very very very bad iron is two or three small pinches of diamonds sprinkled on like a light snow flurry - part of a carat. I'm sure some people waste diamond and can make it expensive, but there is no need to. This is the way irons needing a lot of work should be lapped now.

[Mike Holbrook]

I have been studying the Muji and HNT Gordon Smoothing planes. Gordon's planes are at higher angles like many of the the Asian style planes. One can also reverse these blades and use them more like a scraper. Gordon supplies a TS blade as standard with his planes but suggests using a HSS blade if it is reversed and used as a scraper. Doesn't scraping as opposed to planing make a different finish? Could the scraper like finish be sometimes called a polished finish?

Are the HSS blades harder/tougher due to a higher carbon content or is the difference more of a treatment process thing?

[David Weaver]

HSS (M2) is alloyed with chromium, tungsten, molybdenum and vanadium.

Some of the additives add toughness at high hardness, wear resistance, and temperature resistance. I don't know which does which, a metallurgist would.

the carbon content of M2 is similar to O1.

Scraping definitely leaves a different finish - it is not as good as a planed finish where a plane doesn't tear out.

[Sam Takeuchi]

Are the HSS blades harder/tougher due to a higher carbon content or is the difference more of a treatment process thing?

The main differences come from ingredients. Various amount of tidbits like Chromium, Tungsten, Molybdenum and Vanadium are added to create different characteristics of steel. Even so called HSS, there are loads of different steels fall into that category and each offers different mix of those ingredients and have wear and heat resistance characteristics. So far, M2 seems to be the most popular HSS in plane and chisel blades. I have a good M2 blade made by Paul Williams of Academy Saw Works in Australia. It's a wonderful blade but without a grinder, it's a dreadful blade to work on. It resists being sharpened, too. Proper tools like grinder and/or diamond paste, it can be perfectly manageable, but without that, working with M2 or most other HSS can be a major struggle. So if you are planning to go with HSS blade, do reconsider your sharpening and grinding setup, research into stones or abrasive that can actually abrade HSS.

[Brian Kent]

Here is the comparison that I was referring to, where the high angle Mujingfang scored so high.

http://www.woodcentral.com/bparticles/haspc.pdf

In the Mujingfang terminology, the Polishing Plane is 63° and the Smoothing Plane is 45°. They are completely different tools in practice. The Smoothing Plane is nice for the price, but I could easily live without it. I would not give up my Polishing Plane. Quite often I have a hard wood with really nasty grain and the Polish Plane comes to the rescue every time.

Try it. Really!

The Jack plane is also very good, but I could use it or use something else.

If I am not supposed to post that link, just google:
High angle smoothing plane comparison
By Lyn J. Mangiameli

[Mike Holbrook]

Then this answers the question on the table and another one I have been struggling with. The higher angle planes are designed to make a "polished" finish more like a scraper which is a different type of finish than created by a plane with a 45-common angle. I thought I had seen that polished term being used with the "asian" high angle planes. In fact many of these plane makers take this whole process a step further by suggesting that their plane user might have occasion to reverse their blade to create a finish even more like a scraper.

The blades angled more like scrapers tend to take the wood off in something more like chips than fine ribbons I believe, more like scrapings from a scraper. I believe the common pitch blades are sort of lifting the grain up which is where tear out may occur. The higher pitched blades approach the grain of the wood at a different angle allowing them to sever the grain easier, but preventing the beloved fine ribbons of wood from forming. These plane designs might even beg the question of whether or not the goal of fine ribbons of wood rolling off our planes is as laudable as we have come to believe.

A quick look at a review of Gary Blum's planes done by Derek, in which he tests Gary's 50 degree fore plane against an HNT Gordon Asian style plane with a 60 degree pitch reveals that Derek has both of these planes producing shavings that are more chip like than ribbon like. Derek even seems to get this type of wood chips from the Lee Valley LA Jack which confused me a little until I found an explanation, with explicative drawings on HNT Gordon's site " Blade Angles". Gordon's site finally illustrated for me how cutting angle vs blade pitch is calculated with a bevel up plane blade.

Interesting stuff!