# Corrugated bottom on plane?



## RussellAP (Feb 21, 2012)

Can someone tell me the advantages or lack, for having a plane with a corrugated bottom?


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## jacob34 (Mar 14, 2012)

I just watched a video on hand planes http://www.woodworkingonline.com/2009/04/17/podcast-40-three-hand-planes-every-shop-should-have/ where at the end the question was asked and he felt that it was a marketing ploy that serves no real purpose. Although I do not think he was an expert on the subject and I am not either.


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## BTimmons (Aug 6, 2011)

The grooves mean that there's less material that's contacting the board surface that the plane rides on. That means a little less friction, and it also means less time is spent flattening the sole since you don't have remove so much metal. You see hollows and grooves cut into the backs of Japanese chisels and plane blades, too. For one thing, the steel they use is extremely hard so it makes sense to have less surface area to flatten while sharpening.


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## HillbillyShooter (Feb 15, 2012)

The corrugated bottom reduces drag and is more beneficial in the larger planes, i.e. 5-1/2 and above.


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## Dwain (Nov 1, 2007)

I would agree with the marketing idea. It seems that after building a pretty good plane, Stanley (Bailey) needed to find a reason for us to buy other planes. I agree with every said above, but I don't think those reasons are really appreciable. I know all of my type 11's are corrugated. I just like them more…


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## ShipWreck (Feb 16, 2008)

I have two "C" planes in the collection so far. They do smooth alot easier.


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## RussellAP (Feb 21, 2012)

So the C designation means corrugated.


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## BillWhite (Jul 23, 2007)

Russell, I've got both. I can't see any difference in performance. There might be an argument as to whether the "c" planes are easier to flatten (if needed), but I don't know of anyone who has whined about not having "c" soles.
To me it is kinda like which pasta do ya like best.
Bill


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## donwilwol (May 16, 2011)

A lot of experts agree its was a marketing stint. I agree with Bill, I've tried to tell the difference and can not.


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## cabmaker (Sep 16, 2010)

For me, I prefer a smooth sole simply because it is easier for me to sight the iron alighnment. I do have a few C s however but that is not by desighn. A C sole will function with a bit less resistance but not enough to loose any sleep over. Jacob, your observation is accurate, there are many, many videos on the subject and some are conflicting. Best to talk to someone that have used the things professionally.


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## donwilwol (May 16, 2011)

I believe it was Paul Sellers that didn't like the corrugated soles because he thought they would get clogged. I actually prefer a smooth sole on a jointer, although both my #8 and #608 are corrugated.


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## Smitty_Cabinetshop (Mar 26, 2011)

In use, there is none.


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## Smile_n_Nod (Jan 20, 2011)

It may seem counter-intuitive, but grooves shouldn't have any affect on the amount of friction that a plane experiences when it's pushed across a board.

Friction force is equal to the downward force (due to gravity plus the force you are exerting on it) times a coefficient that depends only on two materials in contact. For cast iron and oak, that coefficient is 0.49. So, if your plane weighs 7 lbs (like a jointer) and you add 3 pounds of downward force to it, the friction force as the cast iron plane is pushed over an oak board is 4.9 lbs. It doesn't matter how much or how little contact area there is between the cast iron and wood; the only things that are important are the downward force (10 lbs) and the coefficient of friction. If you put paraffin or a light oil on the sold of your plane, the coefficient will go down, perhaps to as little as 0.075, which means your friction force would be 0.75 lbs.

(Whew-that's enough geek talk for one day.)


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## davidmicraig (Nov 21, 2009)

Personally, I would think the chief advantage would be in flattening the plane itself. Corrugation would translate to less material to be removed from the plane body.


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## TopamaxSurvivor (May 2, 2008)

A friend of mine hand planed a truck load of walnut stock blanks. He told me the corrugated was much easier to push.


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## ShipWreck (Feb 16, 2008)

To be honest, I feel no difference in resistance/friction on the shaving stroke between the smooth and the corrugated.


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## lwllms (Jun 1, 2009)

There are disadvantages to corrugated soles. If you're working the edges of stock that's thinner than the corrugations are wide, you can end up with the stock trapped in a corrugation. I only had this happen once but then I didn't use corrugated soles on thin stock after that.

The biggest issue is the wear pattern that develops. Look at the sole of a corrugated vintage plane that's seen much use and you'll find wear streaming off the ends of the corrugations. In severe cases, like the 607 below, the wear pattern can cause grooves through the mouth. In this case it would take significant lapping to remove the grooves that stream from the ends of the corrugations.


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## TopamaxSurvivor (May 2, 2008)

Wonder what causes that wear in line with the corrugations?


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## RussellAP (Feb 21, 2012)

There is a void in the corrugation which allows the wood to be higher,then when it comes out of the corrugation it wears.


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## Loren (May 30, 2008)

In resinous woods like pine it gives less surface for the resin
to gum up the sole. This in my opinion is the friction factor
thing. In hardwoods it's possible there's less drag due to
suction as the board becomes very flat, but this is difficult
to prove one way or the other I think. With the sappy 
softwoods though the corrugations help the waxed plane 
slide better in my experience.


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## Martyroc (Feb 1, 2012)

Hi Russ, I have 2 planes, both types I use them equally, I have never noticed a difference but I will try to pay more attention now. I know as long as I keep them razor sharp, I get a good smooth surface and some lovely wooden ribbons.


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## TopamaxSurvivor (May 2, 2008)

I suppose my buddy was using a jack plane to flatten his roughed out walnut stock blanks, but I don't know for sure. He talked to quite a few people to get ideas and said the corrugated plane made a world of difference. He was offered $100,000 for his pile of stock blanks and turned it down. When I say truck load of walnut, it was truly a truck load. He had a lot of experience. I asked him why he didn't get a planer. He said he was getting too fat ;-)


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## russde (Aug 17, 2010)

Remember how a lot of young folks with import cars had wings on their trunks a few years back? Why? They didn't go fast enough to create any down force to speak of…
Same idea with the corrugated soles. Looks cool (I've got 2, I like 'em, can't tell any performance difference, but, I like 'em), that's it.
My three cents…
Russel


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## affyx (Jan 1, 2008)

Brett's friction math is cool!

just spent 40 minutes scraping old paint and pitch and who knows what out of the 'C' in the 6C I'm rehabbing… at the moment I prefer flat soles


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