Friday, 9 July 2010


A few months ago - while attending a Lie Nielsen sponsored hand-tool show, I think I formally busted a myth. The event was held at Exotic Woods in Burlington and we were surrounded by wood, glorious wood. I was talking with a gentleman who was very interested in infill planes and wanted to review some of their features and to get my opinion on why they work the way they do. He rattled off the usuals; they are heavy - requiring less downward pressure, have a really thick iron which reduced chatter, few moving parts - fewer “tolerances” that can add up to movement (chatter), dense woods that dampens vibration, a closed tote which gives a much more responsive feedback than an open tote. As I was standing there - with a clear view of the instrument parts room over his shoulder, I blurted out;

“well... I am not really convinced that dense woods like rosewood are absorbing vibration. In actual fact, they are the worst choice for reducing vibration... they are tone woods, and highly prized for their ability to vibrate.”

There was a very long, awkward silence, and as I stood there pondering what I might have let out of the bag, I realized I had been thinking about this for some time, but had never articulated it that clearly before. And certainly not in public. The conversation continued for at least another 40 minutes and ended after he had happily tried every plane on the bench. So there it was - out in the open. And lightning did not strike me down and the earths axis appears to be unaltered.

In hindsight - it felt pretty good to toss the monkey wrench... but it did get me thinking more seriously about why infills work the way they do.

Another often quoted advantage of an infill is their weight. I am not entirely sure about this one either. I think there is some confusion between “weight” and how solid the plane feels in use. One of the true advantages of an infill plane is the lack of moving parts as they relate to the blade. The blade is fixed (crushed actually) against a wooden bed that is permanently, mechanically fastened to the frame of the plane - the metal body. The lever cap exerts an incredible amount of pressure against the blade leaving it with only once choice - to cut wood. Contrast this with planes where the blade can be moved by way of a mechanical mechanism to move it up and down, and left and right while the lever cap is deployed. Then factor in the frog being able to move forward and back at the same time. These are all great features - but they do add up to “tolerances or gaps” that reduce how rigidly the blade is held when it is presented with challenging timber. I think people experience how solid an infill feels more than the actual weight. This weight vs solid issue also explains why a Clark & Williams plane feels so great to use. Like an infill - they have no moving parts. The blade is held firmly against the bed and the iron does not have a choice but to take a shaving. The first time I tried a C&W smoother - I nearly tossed it across the room because it was so much lighter... but I very quickly adapted to it, and while it is very different from an infill plane - it does “feel” quite similar - like pushing a rock that spits out shavings.

Those of you that use or have tried both - I would love to hear your thoughts and opinions.


Blogger matt@thuja said...

As a piano researcher (and a former acoustical engineer) I'd have to agree with you Konrad! One easy way to think about vibration is to imagine something really stiff like a piece of metal and something really floppy like a piece of cardboard. Now imagine holding each in your hand and hitting them with a hammer. The stiffer object will transmit the energy without absorbing much of it, while the floppy object will absorb a lot of energy and won't transmit much. Generally speaking denser woods are stiffer than less dense woods, so theoretically a balsa infill plane would probably be the best at absorbing vibrations. That said, in the long run your arm, hand, and muscles are going to be a lot less stiff than even a balsa infill, and its probably mostly at this point that most of the chatter would be absorbed regardless of the plane type.


12 July 2010 at 16:34  
Blogger David Weaver said...

I have only tried planes that I've built vs. bench planes. One of my smoothers has a brazilian rosewood infill, and it feels more solid than the LN 4 1/2 that I had until I finished it, even though the LN weighs more by a couple of ounces (it is 3/8ths wider than the infill in cutting width, though).

I think the advantage in an infill is the tightness of the tolerance around the mouth, it's fixed there, and the attention given to the bed and the fit of the lever cap - nothing moves at all - especially on a plane without an adjuster. The whole plane is a unit and everything is gripped tightly.

If the wood was that good at reducing vibration, we would project it past the back of the mouth at the bottom of the bed and never let the iron touch a metal bedding block at the bottom or the sole of the plane.

I think you're absolutely right.

13 July 2010 at 06:46  
Anonymous JeffB said...

There is a big difference between the vibrations in a thin piece of wood (as used in a string instrument) and those in a big honking chunk as used in an infill plane. Even if the big chunk vibrated in any appreciable way, I doubt it would have any effect given all the other parts of the plane/cutting operation involved. The infill makers used rosewood and other exotics because they looked nice, end of story.

It is interesting to note that Norris switched to ebonized beech later on when rosewood became too expensive. I can't say I have ever heard people complain that the later Norrises perform worse than the older ones. They don't look as nice though.

When discussion of infill weight comes up, it is usually in respect to momentum -- once you get it going it is more likely to keep going. No idea if this really confers any advantage.

13 July 2010 at 15:05  
Blogger Konrad said...

Thanks for the feedback Matt and mentioning ones arm and hands as a dampening device - I would have never thought of that! I wonder if ones arms and hands are enough to eliminate the issue of vibration altogether... regardless of the way the plane is built?


15 July 2010 at 08:28  
Blogger Konrad said...

Thanks David,

First off - congratulations on building your own plane. I am sure it was tremendously rewarding and then using it for your own work is likely pure bliss.

Thanks too for mentioning the fixed mouth - I agree that it is another key to an infills success.

On the adjuster front - one of the reasons many of the original Norris adjusters are in such terrible shape, it that if just one person forgets to relieve the tension of the lever cap while using the adjuster - it will sustain damage. I realize this is essentially a design flaw with the adjuster (that it cannot withstand that type of abuse), but it is amazing how quickly the threads become damaged. Many of my personal planes have been damaged at various shows because people do not bother to ask how to use the plane before they try it. This also speaks to the incredible holding strength of the lever cap design.


15 July 2010 at 08:35  
Blogger Konrad said...

Hi Jeff,

Thanks for your comments. I agree that the reason true Rosewoods were used for infill material was because of their beauty - but they also have some other very important characteristics. Once properly seasoned - they are incredibly stable. In my opinion - this fact actually overrides their aesthetic qualities. The other factor is they are quite easy to work - something hand tool workers would have appreciated.

I have heard many Norris users comment that the functional quality of the pre-war Norris planes (the Rosewood filled ones) is significantly higher than those filled with beech. I am sure there are more factors at play other than the change in infill material - but there seems to be a noticeable difference between them. I have not had a chance to compare them back to back, but many of my customers have and they have all concluded they are wildly different.

Thanks for mentioning the momentum issue - it also plays a role in all this.


15 July 2010 at 08:43  
Anonymous JeffB said...

I agree that the reason true Rosewoods were used for infill material was because of their beauty - but they also have some other very important characteristics. Once properly seasoned - they are incredibly stable. In my opinion - this fact actually overrides their aesthetic qualities. The other factor is they are quite easy to work - something hand tool workers would have appreciated.

Agreed. I was intentionally oversimplifying things to make a point. The fact is that all the infill makers were making a premium product and in turn charging premium prices. It would simply be hard to stay in business if you are charging premium prices for something using run-of-the-mill wood. If you look at the costs of making an infill plane, the largest part (by a huge amount) is the cost of labor. The cost of materials certainly factors in but if you look at the cost of a good chunk of wood versus some standard species, that difference is minuscule compared to the cost of labor. Given, as you said, that some of the exotics are easier to work and more stable once worked (both of which lead to less labor) one could argue that using an exotic species might actually save money for the builder.

I have heard many Norris users comment that the functional quality of the pre-war Norris planes (the Rosewood filled ones) is significantly higher than those filled with beech.

Interesting. I have not heard anyone claim that but you certainly would be in a better position to hear such things. There were a number of changes other than wood species so it would be interesting to figure out what is actually affecting performance. Someone else will have to figure it out though as I won't touch a postwar Norris -- ebonized beech just looks cheesy ;-)

15 July 2010 at 10:10  
Blogger Konrad said...

Hi Jeff,

Thanks for your continued input.You are totally correct that labor is the majority of the cost. That being said - one can easily use $200 of Brazilian Rosewood to get a single smoother infill set. Most of the exotics are not available in perfect board form - there are often inclusions or defects to work around which results in in expensive waste.But yes - labor is still the largest part of the cost.

Yeah - Ebonized beech is pretty horrid. I gotta think it must have made those early makers crazy - knowing where they started and where they were ending up.


16 July 2010 at 09:32  
Anonymous JeffB said...

$200 is more than I was expecting but you are using some special wood for your planes. Is that for a smoother or is that for a larger plane? A jointer obviously requires a ton of wood and getting a single piece big enough (especially nowadays) can't be cheap.

I would expect that getting large pieces of rosewood was easier during the early days of Spiers and Norris but I have never really seen any articles or books speak directly to the issue. It would be interesting to read about the trade and what pressures (cost, availability, or both) caused Norris to make a switch.

17 July 2010 at 20:36  
Anonymous Anonymous said...

If Rosewoods are a tone wood that can induce vibration (which they do, at least in thinner pieces) doesn't that apply to the infill bedding on an infill plane?

And yet in thicker pieces I think there is literally no vibration (or harmonic qualities) present. There is mass and weight, though. I think this is why the infill that uses such a wood as the infill "still works". At least as long as the mechanism that affixes the blade to the bed can create and maintain firm contact.

The issue of creating and maintaining firm contact between the blade and bed also applies to how one affixes a board to their bench to plane it.

If a board is thick and stiff enough, clamping between bench stops is "fine." Once a piece is thin enough to flex slightly due to perhaps too much clamping force, the piece, while looking flat on the bench, will not plane as easily as one that is using something pressing the piece into the bench like holdfasts.

The holdfasts create a fit between work piece and work holding device akin to a plane blade being held to the bed.

Ok. Not enough coffee and too much thinking.

Take care, Mike

21 July 2010 at 09:29  
Blogger Konrad said...

Hi Jeff,

Some of these timbers are frightfully expensive - but they should be. As another point of reference, a mediocre Brazilian Rosewood guitar set sells for $1,000.

I would also love to know how much the cost of timber factored into Spiers and Norris planes. I suspect more than we think. I am reading a book on John and Thomas Seymour right now, and there are many references to the fact they invested heavily in the finest timbers they could find and use them as a business advantage. Wise guys those Seymours.


22 July 2010 at 07:52  
Blogger Konrad said...

Hi Mike,

Two great comments back to back - keep drinking the coffee my friend.

Interesting question - does the volume of rosewood lessen or negate its tonal qualities? That might be something for Matt to answer - I will check with him.

I do totally agree that a big part of an infills overall functionality is the manner in which it is put together. Mechanical fasteners that are not designed to move.

Thanks too for the comparison to planing a thin board. It has been so long since I have held a board between bench dogs, I had forgotten about this effect. It also gives insight into why planing against a single dog or stop works so well regardless of the thickness of the material.


22 July 2010 at 08:07  
Anonymous carlinsand@gmail said...

A little over a year ago I created an infill plane, a big one, with a really steep angle. Think I used Macasar Ebony and overstuffed it, 1/4" steel sole, and 3/16" brass sides, the thing is near nine pounds, there's a 1/4" thick 2" wide Bresse iron with no need for a "chip breaker", no lateral adjustment, no adjustable mouth, gotta hit it with a hammer.
Takes a couple minutes to set it up, but once it's there, I have yet to find a piece of wood it will not turn to glass.
There is NOTHING like an infill, I don't care what amount of tech you throw at it.

8 August 2010 at 21:37  
Blogger JW said...

So, this thread has been banging around inside my brain for a while now.

I think your point about damaged mechanisms is an interesting one. It led me to think about how the traditional stanley 'lever cap' with the little snap lever at the top, doesn't tighten very well without a screwdriver, and seems more designed to allow free movement of the blade when the adjustment knob is turned, or the lateral adjust lever... mechanisms which would otherwise be damaged.

It's to the point where I'm considering trying to retro-fit a "real" lever cap to my L-N #4, drilled through the sides and all.

Konrad, any advice on home-brewing a nice lever cap? I'm half tempted to strip one out of an old Mathieson that I've had kicking around for a while, since it was crookedly installed, and has made lateral adjustments essentially impossible...

13 August 2010 at 10:59  

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