Thursday, July 26, 2012

Joint Decisions

I decided to move on from my Oliver 166 16" jointer, and have secured a purchase deposit from a buyer. I'm looking for a slightly wider jointer, a slightly longer jointer, and preferably a jointer with a 4-knife cutter head, ideally Tersa.

Now, at the moment in N. America there is somewhat of a dearth of machines fitting the above description. I look daily, and I look in all the usual spots, and in some not-so-usual spots. The average jointer for sale in North America is a 6" home-shop machine. There's a slightly smaller number of 8" jointers, usually designed in a similar way to the 6" machines, that is, not very well, and then there are a few 12" machines to be had. If I was to hazer a guess, I'd say that less than 5% of what's available are jointers larger than 12", and most of those are 16". A tiny number of 20", 24", and even 30" machines rounds out the picture. The vast majority of the 16" and larger jointers are old hunks of American 'arn ("iron"), some of which dating back 100 years or more, and often having had zillions of linear feet of stock run over them.

Now, once in a while, when I have drool to spare, I head on over to some German heavy metal sites, chock-a-block with ridiculous jointers. It's somewhat akin to a religious pilgrimage. In Germany, the typical jointer is 20", and machines in the 6"~12" size are a distinct minority. I get the impression that the hobby woodworker market there is somewhat small.

As i look through listings of a couple of hundred beautiful jointers, ranging from dirt-cheap to not-so-cheap, I noticed that jointer deisgns vary by more than one would think. After all, when you think about it, the jointer primarily does two basic things:

  1.  Flattens a surface on a board
  2.  With the first surface flat, an adjacent surface can be made flat and square to it

Not much going on really - one would think the physics of this machine had been long resolved. However, looking at jointer after jointer I notice interesting variations in all sorts of things, and not simply color or size. Take fence placement. On the Oliver, and a lot of the older American tanks, the jointer fence is a 100+lb. affair held onto the outfeed table with a pair of large heavy locking screws. Many of the German and Italian jointers also affix the fence to the outfeed table. Here's a couple examples:

Kölle:


Martin T-52:

Quite a few jointers however, have the fence connected to the infeed table side:

Hofmann AHW 500:


Rex:



I could list more makes yet - it appears that the fence attachment to the infeed is the most common one, which I found a surprise.

And then there are jointers in which the fence is supported independently of the tables, in which case the fence pivot mechanism is often centered, more or less, over the cutter head:

Ascom DE 410: 


Schelling A-41:


Panhans:


Kölle AH40:


Kölle seems to have changed their design philosophy from the one pictured at the top of this page with this newer machine. I wonder why?

Baeurle AS510:


Casadei DS510:


Dorna F500:


The monsterous Gubisch AL-4:


Olma:


 RGA FC410:


 Schneider AFK 5:


Now, I think the Japanese also make some sweet cast iron monsters too, you just really don't see them much outside of Japan. The typical Japanese jointer is slightly smaller than the average German machine, typically in the 300~350mm width zone.

How do they situate their jointer fences?

The Matsuda MNT-400 goes for the outfeed table position:


Many Japanese jointers place the fence on the infeed side:

Shimohira HA-300:


Shoda 300:


Love the cast iron 'door' on the left side pedestal on that one.

Takagi 250:


Yasuhara P-350LDX:


And then there are ones with the fence fixed to the chassis, not the tables, like this Taiyō RH-250A:


Though the fence does not attach to the outfeed table, the fence pivot point, the stiffest portion, is on the outfeed side.

So what to make of this? Which different theories are at work, and why? It's got to be something other than patents and limitations that arise that way.

It seems to me than the infeed table aligns the work for feeding to the cutter head, and the longer the infeed table the better. There are several German jointers, and one Japanese model that have 1.8m (6') infeed sides. The inffed table is the one which is adjusted up and down with frequency to change the depth of cut. The outfeed table is generally kept in the same place, which is a hair (a couple of thou) below T.D.C. of the cutter head's knife circle. It is the outfeed table which is most responsible, I think, for creating a flat reference on the stick. So, for the initial jointing of one board face, as the fence is not involved in the process, it really doesn't matter much where the fence attaches.

When performing the second jointing operation, jointing a 90˚ adjacent face to the first, that fence position makes a difference possibly. In this operation, the stick needs to be held closely against the fence, which may require some pressure if the stick is heavy and the board wants' to tilt away from the fence at top or bottom arris. Ideally, you don't want any deflection with the fence at this time, and this is where having the jointer fence attached to the infeed seems to make more sense. And I am jut now coming to this conclusion as I write this.

The disadvantage to having the jointer's fence connected to the infeed is that when you lower the infeed table for a deeper cut, the fence may bottom out on the outfeed table. So, either the fence has to be configured with a bunch of space under its edge along the outfeed portion, or the fence pivot mechanism needs to allow for the fence to be re-positioned. A similar problem happens with the fence attachment to the outfeed table - when the infeed is lowered for a heavier cut, the fence ends up with a fair amount of space under it at the infeed side, and this can cause problems in certain situations.

I think one definite advantage to having the fence attached to the chassis of the machine rather than either table is that the weight and position of the fence can have no effect upon the setting of either table. Depending upon how perfect the castings are for the jointer table supports, a little weight shift here and there can cause a table to slightly tilt or tip.

finally there is one other place in which jointer fences get attached: to the far end of either the infeed or outfeed table. This design is seen on most jointer-planer combo machines and is decidedly a drawback. Such fences, which are often aluminum extrusions come from a company called 'flexomatic', if you catch my drift. I'll never buy another jointer planer machine again for the simple reason that their fence system is crappy.

Thanks for coming by the Carpentry Way. I welcome hearing from readers in regards to which jointer fence design makes sense to them, once any drooling has subsided. Love those big jointers!

Monday, July 23, 2012

The Nest of the Lotus Flower (II)

This is a follow up to the previous post, specifically in regards to a question Ward Wilcox asked:
I have heard there are a two or more lines of Sigma Stones. The line sold by Lee Valley are different than the ones Chris purchased. Do you need to soak the Sigmas? The Sigma display on Lee Valley claims they are soft but cut very fast. DJY states the 1000 grit is too slow if I understand him correctly. How do Sigmas measure up to Shapton pros?

I asked Stuart Tierney of Tools from Japan to provide an answer, as he has a much better picture of the scene than I do, and here's what he wrote - detailed and long enough to merit a second post in this thread:


Hi Ward, Stu here.

There are indeed two 'full' lines of Sigma Power stones, plus a 'back catalog' of various others that nobody you know of (except me) has heard of.

The one LV have are 'Select II' from the updated original series. Let me explain...

Originally there were 2 'Select II' stones, the #1000 (grey) and the #10000 (yellow). About 2 years ago, give or take, Sigma Power expanded the 'Select II' line with a #240 (bright green), a #3000 (darker green) and a #6000 (orange/yellow).

These are singularly unique stones. All use Silicon Carbide as their abrasive and have NO binder. Every other manufactured stone has a binder of some kind to hold them together, these ones don't.

This is a double edged sword...

It's good because Silicon Carbide is very hard and will cut virtually any blade steel with ease, and because there's no binder the entire stone is 'good stuff'. So they'll cut anything and do it very quickly.

It's bad because a binder tends to allow the maker to adjust the 'friability' of the stone, in essence, how quickly the stone breaks down with use. With these 'no binder' stones, that 'adjustment' is lost to a large extent. It's very apparent in the 3 coarser stones (240, 1000, 3000), less so in the finer 2 (6000, 10000) because the finer stone's particles are smaller and in better contact with each other, they tend to 'hold together' a little better.

The funny thing is, this 'friability' is only a concern when the steel is relatively soft and easily abraded. These stones were specifically developed for High Speed Steel which is usually quite hard and very tough, both making it quite difficult to abrade with conventional sharpening stones. If you use hard HSS on these stones, they change significantly into stones that are actually quite 'flat', still fast and very effective. On 'normal' steel, they do tend to dish a little faster than I'm happy with, but they do work faster than almost any other stone so the dishing is less (because they work faster) than it might otherwise be. 

There are 3 additional stones with the 'Select II' label now, a #400, the #1200 Chris has here and the #13000 which is also shown here.

The #13000 has been around for many years, but Sigma Power have changed the label on it from 'ceramic' to 'Select II' as internationally, the Select II branding is more widely known and recognised. The stone is the same, the label has changed, nothing more.

The #400 originated late last year from a request for a stone that was coarse, but showed stronger dish resistance than the #240. 2 stones were produced, a silicon carbide stone similar to the existing #240 and a white alundum (WA) stone, with a binder in it. The SiC stone was an improvement over the #240, but still dished too quickly. The WA was not as fast as the SiC stone, but the dish resistance was excellent. As that was the desired property, the WA stone went into production. As it deals well with HSS, it was no concern to use the brand recognition of Select II on this stone, so that's what it got. A pink label no less...

(It was cheaper too. I still have both prototype stones and would like to see the SiC stone go into production as well. The knife sharpener folk will love it!)

The #1200 came into being from concerns about the Select II #1000 dishing too rapidly for many tool sharpeners when used with Western style tools. I asked for the same stone with some binder in it to 'firm it up' a little. The straw that broke the camels back was the FWW review where the ceramic #1000 did quite well, but the Select II #1000 did poorly.

The #1200 was the answer to that.

The Select II #1200 is again, a WA stone. The abrasive is finer (genuine #1200 grit), the ratio of binder to abrasive is changed toward more abrasive and the binder is a tougher, less likely to break down type.

As a result, the #1200 is very hard, has very strong dish resistance but still works quite quickly. Because of the high ratio of abrasive to binder, this stone still works well with HSS and also deals with 'normal' steel well.

Now here's where the line is blurred somewhat...

The #1200 has a Select II label on it, but it's closest relative is the older Sigma Power 'ceramic' line of stones, specifically the #1000 'hard' and not the Select II #1000.

The 'ceramic' line of Sigma Power stones have had sporadic availability outside of Japan for quite a few years. When I first started my little store, I made sure I was able to get these stones and make them available on a more consistent basis.

Not long after starting up the store, I contacted Sigma Power directly (previously through a dealer) and they decided to deal with me directly, which means I 'have their ear' when it comes to new products.

Their 'ceramic' line are more conventional stones with a binder in them, in this case it's a true 'ceramic' type binder and the name reflects this. In many other 'ceramic' type stones, the ceramic signifies the abrasive is a manufactured abrasive so is consistent and tougher than naturally occurring types. In the case of other 'ceramic' stones, the binder may be a ceramic material (fired at high temperature and fused together), a resin, a plastic or a baked binder. These binders allow the maker to fine tune the working characteristics of the 'stone' (is a plastic/WA concoction really a 'stone'?) to get what they want from it.

Anyway, the Sigma Power ceramic stones all have a binder in them and are available in #120, #1000 (hard and soft), #2000, #6000, #8000 and #10000 as well as the #13000. The #120 has SiC abrasive in it, the rest use WA (except the #2000 which has pink alundum. Long story but it's slightly different) and are fired in a kiln similar to a coffee cup.

They come from the same company, the labels are different but the ceramic were the 'original' stones, the Select II are newer and borrow from the 'ceramic' line when appropriate.

And the #6000 above?

It's from an even older line of stones, before there were 'lines' of stones. It got the 'ceramic' name when Sigma Power stuck a base on it.

So it's technically a 'ceramic' stone, just as the Select II #13000 is technically a 'ceramic' stone and the #1200 is in Sigma Power speak more a 'ceramic' than a 'Select II'.

I hope that's not too confusing, but with these two lines of stones borrowing from one another it never going to be an easy task to completely separate them.

Stu.

Friday, July 20, 2012

The Nest of the Lotus Flower

I seem to keep working my way through the sharpening stones, and it was time to order up so new ones. I had heard some good things about Sigma Select II stones, and tend to like ceramic stones a fair bit, so I ventured a contact to Stuart Tierney at Tools from Japan. Stu is one of those fellows who who will really take the time to answer your questions and writes quite detailed emails. i like that. I told Stu that I would wrote about these new whetstones, and he gave me the stones at a very reasonable price in some exchange for a plug here on Carpentry Way.

My recent stones were a mix of brands. A New Kent 1000, a KitaYama 2000, a Shapton Pro 5000, and a Naniwa (Ebi) 10,000 stone. The Naniwa has a bit of talc or something like that in it which gives it a feel I like fairly well, but the stone wears down fairly fast. I'm on my third one and was looking for an alternative.

I ended up getting three Sigma Stones, from left to right, a 1200 grit, a 6000 grit, and a 13,000 grit:


The 1200 is described on the box as a 'middle stone' (中砥) however I tend to think of stones under 2000 as more or less coarse. The 1200 is a decent size (210x75mm) and nice and thick at 25mm:


The 1200 is a ceramic designed for high speed steel and powdered metals, which other brands of ceramic stones can struggle with I have found.

The 6000 comes in a different box for some reason and is also a ceramic. The stone has fine pink dots on it and has some writing on one side:


Whatzit say? Well,  "人造蓮華巣板仕上砥", or jinzō-renge-suita-shiage-to", which is man-made (人造) lotus flower (蓮華) 'nest-plate' (巣板) finishing (仕上) stone (砥). Lotus flower presumably refers to the colored pattern on the stone. 'Nest plate' or suita is a word normally applied to natural stones and refers to stones which have streaks or dots of color in them, that is, incursions of other material, which might mean a soft stone substrate with little hard bits in it or other configurations. In this case, the term renge-suita (蓮華巣板)refers to the pattern of incursions looking like a lotus flower.

Here's a picture of a natural stone of the renge-suita type:


Next, the 13,000 Sigma Select II:


I have been running a variety of blades over these stones for the past few weeks, including white steel blades, blue steel blades, super blue steel, and western A2 steel as well. The results have been uniformly impressive, These stones are all fast cutting, do not dish quickly, and do not clog. A perfect world of artificial stones if there ever was one. These three are my new favorites and I have put my other stones away for the time being.

Just to give an idea, here are some pictures of a Funahiro paring chisel through the three grits.
First, after the 1200:


Then the 6000:


And the 13,000:


A little blurry that one as it was tricky getting the camera to focus on the mirror.

A few different chisels, of differing steels and makers, taken through the rounds with these three stones:



Another addition to the sharpening set in recent weeks has been a DMT DiaFlat sharpening plate:


This plate comes with a certificate guaranteeing flatness to within 0.0005", and the diamonds come mounted on a good size chunk of steel plate:


It's a hefty piece of metal, and needs no additional hand pressure to flatten stones:


This plate seems a tad coarse to begin with and leaves scratches on the stones, but like many diamond plates it settles down after awhile and isn't quite so aggressive. This plate replaces my sandpaper on granite plate method I've been using for the past year (after the failure of my Shapton Glassstone diamond plate). The sandpaper gets messy quickly, and the wet/dry sheets don't last all that long so eventually it isn't all that cheap a way to go. With a flat support plate for the paper, it can be very accurate however. I'll go with this diamond plate for a while. An advantage to the plate of course is its portability (in comparison to a 3" thick granite 12"x18" surface plate at least!).

Sharpening is one of those unglamorous but vital aspects of woodworking with hand tools and a rewarding activity in its own right. It's a bit sad that almost all of the western magazine articles one comes across about sharpening involve how to make it quick and easy, a chore to be overcome as quickly as possible. I would suggest that to truly progress in sharpening - or any skill-based activity - one must abandon the idea that is is some sort of burdensome task to be grudgingly got through, or gotten through with the aid of gadgets and little thought, and move to a place of being present and engaged with the activity. Sharpen, use the tool, observe, adapt, Repeat. In time you figure a few things out, and discover more things you didn't know. That's how it goes.

Thanks for coming by the Carpentry Way. I'll say in closing that if you are looking for some new sharpening stones, Stu at Tools from Japan is a great guy to deal with and will give you patient help and great advice. Highly recommended. On to part II of this rock talk.

Thursday, July 19, 2012

Holy Mackerel: Meet the Supersurfacer

Hopefully the logic of this post title will become apparent when you see this page on Kyōto Kitayama Lumberjack Sushi.

I really feel like 'posting' another link today: Kitayama Forestry Products

Isn't this gorgeous?:


That's one of the things that is great about Japan - the diverse selection of high quality wood and prepared architectural components - at a price of course. Respect for the beauty of a natural material, and a nice touch in how it is manipulated too.

I'll have a post tomorrow reviewing some new sharpening products that came my way recently, and will be following that up with another installment in the 'Chip off the Old Block" series-  thanks for visiting and hope to see you next time.

Wednesday, July 11, 2012

Chip off the Old Block (IV)

Towards the end of the last post in this thread I made mention of the point that a chipbreaker can allow a plane with a blade bedded at a low angle to deal with tear out. What is tear out exactly, at the level of interface between cutting edge and wood? Well, it is a condition in which the shaving, or chip, being lifted off the surface of the wood by the cutter does not break or sever as it is bent but rather is pulled, not unlike a thread being pulled from a garment. This can happen when the cutter is dull, and/or the wood fibers are resistant to being cut, and/or the wood fibers are long and not running in a direction conducive to easy cutting, or the angle of the cutter is not sufficient to break the shaving. As the cutter advances, the shaving is partially ridden over by the cutter and dragged, and as it is dragged the shaving fibers pull down into the wood and tearing begins. When planing against the grain, the lift of the chip can also propagate separation slightly ahead of the cutter, and down into the surface. As the cutter moves further along, the the dragged shaving fibers are pulled tighter and pressure increases at the cutter as more wood if fed into the edge, and the shaving either is torn across its fibers or severed imperfectly. The resulting surface is a bit like a garment with a thread teased out here and there, broken here and there, and since the fibers have uplifted and torn, the damage is slightly below the planed surface. This then necessitates taking several more shavings to flatten the surrounding surface down enough to clean up the site of the trouble, but if the grain or material is not cooperative, then getting down to the point where the mess can be cleaned up leads to yet more tear out. Eventually what is being torn out is one's hair, as these sorts of tear out event often occur just as one is dressing a surface down to final dimension.

The addition of a sub-blade atop of the primarily cutter lends a certain amount of stiffness to the blade edge, pre-tensioning it so that it is more resistant to deflection, but more critically the sub-blade can change what the shaving does and enable the chip to be broken so as to lessen or eliminate (ideally) tear out. Here's the layout of a Japanese smoothing plane with chipbreaker fitted:


A Japanese plane with sub-blade, osae-gane, is typically delivered to the user with the sub-blade ground to a 20˚~25˚ angle. Given a standard main blade bedding angle of 40˚, the effective angle produced by the 20˚ sub-blade is 60˚:



In some woods, 'friendly' woods we might perhaps call them, an effective angle of 60˚ is going to work fine. However the perfect walk in the friendly woods is more of a rarity than a norm. The wood grain direction often reverses on sticks cut tangentially from a log with a slight bow, and woods with interlocked grain are most uncooperative when dealing with vertical (radial) grain surfaces. For general purpose planing, the normal practice is to place a second bevel on the chip breaker. This second bevel is typically honed at 70~80˚, relative to the sharpening stone:


With this second chipper bevel, the effective angle the shaving will follow increases significantly, which concomitantly increases the leverage of the assembly to break the chip, thus reducing tear out:


This combination means that one can have a lower angled plane, and that helps in terms of taking a clean slice off the surface, while the osae-gane causes the shaving to soon bend back and break, thus mitigating tear out.

Now, how much of a secondary bevel to put on the osae-gane is another question, and opinions vary somewhat. I've seen some people show the bevel being put on with a single stroke of the blade on the stone, angling the sub-blade up to 80˚ in one stroke and that is it. Obviously that would put an extremely small secondary bevel on the blade, and my thinking is that such a bevel is not especially effective, if the purpose is to have a secondary bevel to increase the chip-breaking leverage. If you grind too much of a bevel, then the sub-blade needs to be pushed down further, and in concert with a tight mouth opening, the likelihood of chips jamming in the mouth increases. I take about a dozen passes on a medium stone followed by another dozen on a finishing stone, and a few swipes on the back to remove any wire-edge. This is done on the initial set up of course, and not every time you sharpen up! The secondary bevel is visible to the eye, and has a width of around 0.3~0.5mm. Ultra thin shavings, with the accompanying tight mouth and minimally set blade, might have a chipbreaker set with was secondary bevel width of 0.1~0.2mm. Obviously, it makes sense to have middle and finishing planes set up to reflect this.

I think in general, the tighter the mouth the smaller the secondary bevel must be to avoid chip jams. Tighter mouths help keep the shaving pressed down close to the cutting edge, and this helps also with tear out, but it isn't quite as large a factor in obtaining good planing as some would suggest. Those taking thicker shavings in the act of rough dimensioning can have a larger mouth opening and a larger secondary bevel on the sub-blade.

Another question is, how close to the cutting edge should the lead edge of the sub-blade be? If you've seen the planing video linked to in the first post in this thread, you can observe the results of setting the blade at 0.1mm, 0.2mm, and 0.3mm.  The conclusion reached in that demonstration was that setting the chipbreaker closer reduces tear out. What was not stated so well in that video was the relationship between cutting depth and chipbreaker setting. Imagine what would happen if you took a thick shaving, say 0.5mm, and had the chipper set at 0.2mm. The chipper would be buried in the cut and as the shaving rose up the main blade it would be broken backwards by the sub-blade right back into the wood. The plane would have a heavy pull and would perform poorly. The chip needs a place to go, so I tend to think that the lead edge of the chipbreaker should lie more or less on an equal depth with the edge of the dai's mouth opening - the furthest out it can stick without getting buried in the wood surface. That said, if it protrudes a hair beyond that in depth is not the end of the world as the chip will still be able to enter the mouth opening:


There's more to discuss yet, including setting the chipbreaker up on the kanna-mi, and one carpenter's explorations into alternative chipbreaker design. Stay tuned, and thanks for dropping by the Carpentry Way. --- on to post 5

Sunday, July 8, 2012

Gargoyle

Well, now that Wimbledon has wrapped up with a scintillating men's final I can devote some time to the blogging again. I don't generally watch sports much, however I make exemptions for the tennis Grand Slams and the Olympics. It's great that this is available streamed without commercials on my computer.

I will be returning shortly to those various loose ends in the threads I have started, but for the moment wanted to share some pictures of a sweet little gate located in Williamstown MA, about 45 minute's drive away: The Gargoyle Gate which guards the football grounds of Weston Field:


This gate was built, from what I have been able to determine, around 1904, and was a presentation to the town, the location of Williams College, by the Gargoyle Society. I gather it is some sort of secret society founded in 1895. NY Yankee GM George Steinbrenner was one alumni.

A cute li'l building, and very solidly made -  I wish I could find out more about it. This is a view of the front:


The back also has an eyebrow, and one could describe, I suppose, the gable end as having a form akin to a Japanese minoko:


One more:


All for now - should be back to more regular posts this week. Thanks for swinging by the Carpentry Way.