Plane soles should be mostly flat

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Blog entry by Paul Sellers posted 02-18-2012 09:07 PM 10100 reads 10 times favorited 14 comments Add to Favorites Watch

Here is a post I did recently and now want to show you how to do it through a short video. This is not the same plane shown below but it is all the same procedure I use for smoothing planes:

Something I have wanted to post on for a while. Next week I will be using a Stanley #4 at the Springfield New Jersey Show and the Fredericksburg Virginia Show Masterclasses I will be teaching for The Woodworking Shows show. It’s an eBay find for £8 – $12. This plane is and always was an amazing tool in and of itself with no retrofits of metal components at all.

Prepping your plane

Here is my technique for prepping a number four and other Bailey-pattern planes you may own. I hope that this knocks your socks off. No body’s done it before so watch carefully.

First off, how many of you know that you can easily bend most metal-cast planes by merely flexing the handles? This then changes the shape of the sole and many craftsmen I grew up with did this all the time when they were jointing the edges of boards. None of the planes were straight just as many new models made with heavy castings may not remain flat even though factory tested before being shipped. Truth is steel changes according to exchanges of heat and exposure to extreme temperatures is when the greatest change takes shape. Pun intended.

What we aim for is a general goal of flatness and then we work with our planes at a personal and relational level. That’s why it is a rare occurrence to pick up someone else’s plane and feel comfortable with it straight off. Now all of that should help you understand your own plane and the need to develop a thorough and insightful relationship directly through working it.

Following are the steps guaranteed to flatten the sole based on the fact that soles flex with even hand pressure. That is why, when Clifton flattens the soles of their planes they never apply more than 12 pounds of pressure to any part of the plane.

Flattening the sole needs to be done from time to time because they wear in different parts of the sole depending on use and user. This must be

Testing your plane for flex

If you want to test your planes flex, here is simple enough test I put together simply to show that they do. Suspend the extreme ends of the plane on two hard, non-compressing surfaces. Here, I am using two steel-stocked squares.


Cut a wedge that tapers shallowly and is wide enough to engage the under edge of the plane as shown. With no pressure, slide the wedge under the plane until you feel engagement and with a sharp pencil make a mark.


Now, having removed the wedge, press the plane in the centre and slide in the wedge. Now you can see that it doesn’t take a lot of pressure to alter you sole and you will understand why I am emphasizing this key point in both sole flattening and plane use.




 Actual flattening or lapping

The plane must be fully loaded with the cutting iron assembly and under the same general pressure you use in daily use. This varies from craftsman to craftsman so there is no torque-wrench test to govern you.

If necessary, clean off the surface of the sole using abrasive paper on a flat plate of thick, float glass or a dead flat tile. Here, I am using 120-grit paper, which is enough for flattening. I also use my diamond plates for this and they work well too as long as they are truly flat.


Mark the sole across its width and intermittently along the length with a sharpie and return to the abrasive.


Instead of gripping the fore-knob and the rear tote in a bulldog grip like this…


...hold it firmly at the fore part and rear of the sole. You can use the handles, but this must be done sensitively as the extra leverage from the extended handles will readily flex the sole. I learned this years ago when after flattening soles they all somehow seemed to be slightly hollow after checking with a straightedge.


Continue until the lines become so feint you can scarcely see them over the whole width.


Feathering the sole edges

Now if you read my earlier post you will know that older planes and new planes work best if the perimeter edge is well worn so that it feathers in to the flat face of the sole. This allows smooth transition over the surfaces of boards being trued and also where two or more adjacent surfaces intersect. The rim of a box or a framed door are good examples.

Here is the new step that gives the Paul Sellers’ ‘glide-slide’ you want in a plane sole.

Having flattened the sole as directed, tape a steel rule to the surface of the plate so that the plane’s sole glides on the duck tape and the plane sole is slightly angled into the abrasive paper. Keep the sole corner parallel to the ruler and simply move back and forth about twenty or so times. It’s also handy to remark the sole with the sharpie just to make certain you are working evenly.

Do the same to the fore end of the sole; Following the arc.


See now how the edges are gently chamfered uniformly.


File off the heel of the plane if this has not been done previously. This heel is notorious for damaging the corner edges of work on the reverse stroke of the plane in use. Sand off any unevenness from the file.

If you want to you can use finer grit of #240 to give an overall smoother finish, but this doesn’t add anything to the sole’s flatness.

I use furniture wax after abrading. When the surface is newly opened by abrasion it is highly prone to rusting.

-- Paul Sellers, UK

14 comments so far

View bfergie's profile


83 posts in 2398 days

#1 posted 02-18-2012 10:07 PM

Thank you Paul. I’m getting ready to tune up my planes, so this is timely for me. They have been stored for awhile and some I bought new awhile back and some are old ones I picked up. Time for me to get reacquainted and learn.

-- Fergie in CO

View Don W's profile (online now)

Don W

18873 posts in 2649 days

#2 posted 02-18-2012 10:16 PM

Interesting Paul. I’ve always softened the edges but never thought of doing it this way. I will have to give it a try. I’d also note your bevel didn’t go beyond the blade edges. It might be worth mentioning you would want to make sure it didn’t.

-- - Collecting is an investment in the past, and the future.

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Paul Sellers

278 posts in 2652 days

#3 posted 02-18-2012 10:25 PM

You are welcome. This method can be used on any plane. Many woodworkers think that because a plane is new the sole is flat r that plane soles always remain flat, but that’s far from true. Plane soles can 1) Change when temperatures change. 2) Wear down, especially if used mainly for jointed narrow edges of 1” and under. 3) Distort through overheating soles during the flattening process – excess heat easily builds up in non-coolant linishing or lapping machines. 4) Distort during the process through exerting high pressure on the plane body (sole).
These are just things I have seen over the years. One apprentice kept bulldogging the plane down and every time he tried it for true. it was because he was flexing the plane when he offered it to the abrasive.

-- Paul Sellers, UK

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Paul Sellers

278 posts in 2652 days

#4 posted 02-18-2012 10:28 PM

Hello DW,
I think that thats a good point. Thanks for pointing that out.

-- Paul Sellers, UK

View Mauricio's profile


7144 posts in 3233 days

#5 posted 02-19-2012 02:31 AM

Paul this is revolutionary! I have to admit its scares me to feather the edges of one of my planes. It makes logical sense to me for a smoother since it would help you get in to tighter hollows in the wood but wouldn’t it effectively shorten the length of the plane on say a jointer? Only a little I know but still…

By the way it looks like your not going to be Atlanta for the Woodworking show here. Sorry were going to miss you!

-- Mauricio - Woodstock, GA - "Confusion is the Womb of Learning, with utter conviction being it's Tomb" Prof. T.O. Nitsch

View Brandon's profile


4152 posts in 3033 days

#6 posted 02-19-2012 05:29 AM

Paul, great video, as always. I thought, “another video on flattening the sole, what’s there to learn?” But I really learned a lot from your ruler trick! I usually just softened the corners on the soles, but never really feathered them—it makes a lot of sense and I’ll have to give it a try. Thanks a ton! Keep the videos coming.

-- "hold fast to that which is good"

View nobuckle's profile


1120 posts in 2843 days

#7 posted 02-19-2012 06:56 AM

Thanks for the tip Paul. I have an old Stanley No.5 that needs a bit of work, I’ll keep your method in mnid.

-- Doug - Make an effort to live by the slogan "We try harder"

View MNWOODWORKER's profile


105 posts in 3667 days

#8 posted 02-19-2012 07:48 AM

Interesting, I guess I could see on carpentry were rough starting points are more acceptable but for even basic to average woodworking I don’t see it as a benefit. I mean no disrespect here but to me it seems very drastic for a small benefit. By using a few feathering passes to clear any high spot and then standard planing to smooth the surface any irregularities are removed, am I missing something or is it just different views?

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Paul Sellers

278 posts in 2652 days

#9 posted 02-19-2012 07:53 AM

Sorry Mauricio,

This year’s schedule won’t allow me to go to Atlanta.

As a point though, it’s not so necessary on longer planes to feather the edges. The only reason I suggest doing this in the first place is that that’s what has happened to older, well-used planes that make them glide so easily over undulated and uneven sections. If a sole is already flat, it’s only necessary to feather the edges and not reflatten the already flat. As you point out, feathering the edge is only really about 5mm (1/4”). So, its too minimal to be of concern.

-- Paul Sellers, UK

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Paul Sellers

278 posts in 2652 days

#10 posted 02-19-2012 07:58 AM

It may seem that way until you start chamfering or creating roundovers and then the corners of the plane regularly catch on the corners and ‘trip’ the plane and even when slight it still mars the wood. Doing this eliminates the problem for a lifetime of use et takes only a minute or two to do. It’s really just an option and the plane does operate much more smoothly even for smoothing wide surfaces.

-- Paul Sellers, UK

View MNWOODWORKER's profile


105 posts in 3667 days

#11 posted 02-19-2012 08:18 AM

I guess I have just never seen it as a problem when doing it but it is something to keep in the “bag o tricks” in case it ever does become an issue. Thanks for the reply and video, it always takes courage to put something out there that is new or different, so agree or disagree that is admirable. Look forward to more content

View stefang's profile


15881 posts in 3416 days

#12 posted 02-19-2012 10:52 AM

Thanks Paul. Your flattening procedure is all new to me, but I can certainly see the value in it. It’s wonderful to have the opportunity to learn these time tested skills from a generous craftsman of your abilities.

-- Mike, an American living in Norway.

View stefang's profile


15881 posts in 3416 days

#13 posted 02-19-2012 04:16 PM

In support of Pauls claim about the plane sole’s flexing, I came across this article in a 1923 Popular Science article in the link below. Wait until the cover loads and then click on contents, then scroll down to page 55. The test results will surprise you! Live and learn. The world never ceases to amaze you.

-- Mike, an American living in Norway.

View Paul Sellers's profile

Paul Sellers

278 posts in 2652 days

#14 posted 02-19-2012 04:53 PM

Thanks for this, Mike.

I always felt something would be out there with regards to this so thats a useful resource for my new plane book too.


-- Paul Sellers, UK

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