Making a moulding plane: Step 5 – Bedding the iron and fitting the wedge

This is the fifth part in a series on making a moulding plane.  You can read the previous posts using these links:  Making a moulding plane: Step 1 – The blankMaking a moulding plane: Step 2 – LayoutMaking a moulding plane: Step 3 – Making the grip and escapement, and Making a moulding plane: Step 4 – Boring (the Wedge Mortise).

We left off in the last post with the wedge mortise cut and squared up.  Now it is time to bed the iron and fit the wedge.

Bedding the iron is fairly straight-forward.  The first step is to put the blank iron (which can be purchased from Lie-Nielson Toolworks) into the mouth of the plane so that the tang (the long skinny part of the iron) is against the blind side of the escapement and runs up through the wedge mortise. The first time you do this, the result should look something like the photo below.  IMG_2969

At this point, the mouth of the plane should be too narrow for the iron to fit against the bed of the escapement.  The next few steps are to use a float to open up the mouth slightly so that the blade will fit against the bed.  Opening up the mouth will create a slight angle on the front of the escapement (the breast angle) that is called the “wear”.


Go slow when cutting the wear angle.  Only open the mouth a tiny bit at a time and check your progress by inserting the iron after every few cuts with the float.  At this point, you don’t want the wear to look like the photo above, You just want the iron to fit against the bed.

Once the iron will fit against the bed, you want need to start the process of fitting the wedge.  You will have to have the wedge inserted to make sure the iron is properly bedded.  To start, you will need a piece of stock just slightly thicker than the width of your wedge mortise.  For a # 6 plane, we are shooting for 3/16″  The wedge should be cut from this stock so that the grain runs down the length of the wedge.  The angle of the wedge should be 10º.    The wedge doesn’t need to be angled down its full length.IMG_2970

Once you have the wedge blank a little thicker than the mortise, you will start removing a little bit of the thickness at a time until the wedge just fits and takes a little effort to pull out.  To remove this material, you can use a finely set smoothing plane, a float, sand paper, or any other method to remove small amounts of material in a controlled manner.  I prefer to use my crank-neck float.  Remove a little material, test the wedge in the mortise for the proper fit, rinse and repeat.


Once the wedge is the right thickness to get a good fit in the mortise, you will need to work on fitting the angled edges to the bed and breast angles of the mortise and escapement.  To do this, insert the iron blank into the plane body as you did earlier when opening up the mouth of the plane.  Insert the wedge into the mortise and give it a tap with a wooden, plastic, or rubber mallet.  Metal hammers should only be used on the wedge with VERY light taps.  Otherwise, you may end up disfiguring or breaking the wedge.  Look at where the wedge meets the top of the mortise and check out where it comes out of the mortise into the escapement.  When the wedge is well fitted, there shouldn’t be any gaps at the top of the mortise and its front and back edges should be in contact with both the iron and the breast of the escapement.  Unless you are skilled or lucky, you will probably have to make some adjustments to the wedge to get this kind of fit.  If the wedge fits without gaps at the top of the mortise, but there is a gap in the escapement between the wedge and the iron or the wedge and the breast of the escapement, some material will need to be removed from the top part of the wedge where it seats into the mortise.  If the wedge is tight against the iron and breast of the escapement, but there are gaps at the mortise, some material needs to be removed from the tip of the wedge.  Ultimately, you will want to keep both sides of the wedge straight, so when you’re making these adjustments, you are really trying to make small tweaks to the angle of the wedge.

Once the wedge is fit, you can check the bedding of the iron.  Insert the iron into the plane body and tap in the wedge so that the fit is snug.  Check to make sure that the tang of the iron is contacting both the back of the wedge mortise and the wedge.  Then check to make sure that the iron is contacting the bed of the escapement.  If there are any gaps, which there probably will be, you will have to do some more float work to get the bed good and straight.

One way to do this is to color the side of the iron that rests against the bed with a dry-erase marker.  Insert the iron and wedge as described above and tap on the tang of the iron with a small hammer to push it out of the plane.  If you look at the back of the iron, you will get an idea of where any high spots in the bed are because the dry-erase marker will have been rubbed away.  If you look into the mortise with a light, you should be able to see the high spots because of the color from the marker that rubbed of on them.  Use a float to remove these high spots.

Take your time and repeat the process of coloring the iron and testing for and removing high spots until the nearly all of the dry-erase marker is removed.  This will let you know that the iron is well bedded.

I will have to put the rest of this series on hold for a few weeks until I get a grinder and the equipment I need to heat treat the plane irons.  Once I have those in place, I’ll show how to profile the sole of the plane and the iron.

Until next time. . .

3 thoughts on “Making a moulding plane: Step 5 – Bedding the iron and fitting the wedge

  1. Andre

    Great plane build, thanks for sharing your take on making moulding planes, i plan on making a half set of hollow and rounds, i live in east europe there are no used vintage moulding plane on the market, the cost of shipping to my country is very high so i am left with making my own, i have acces to good steel and qs beech, i found the numering sistem online ex #4 has 1/4 radius, but i can find how the wedge and the body sizes of the plane do the body and wedge also grows with 1/16 increments?

    1. Phil Day Post author

      Hi Andre,

      Thanks for your comment.Hollows and rounds are a lot of fun to make. I’ve only made two of the so far, and I need to finish the series on the build on the blog. Your question is a very good one, and the only place I have been able to find sizing for grips and wedges is from the DVD by Larry Williams that I mentioned. There is a PDF with a table of sizes for the wooden bodies of the planes, including the overall thickness of the blank, the width of the grip, and the width of the wedge. Since this is copyrighted material in the U.S.A., I won’t post the information here. That said, hopefully I can get you started in the right direction.

      First of all, there are two parts of the iron on a moulding plane: the cutter (the wide part that will end up being the same width as the radius of the circle you want to profile) and the tang (the thinner part that fits through the body of the plane and is held in place by the wedge). Traditionally, the tang of these irons get wider as the cutter gets wider. So the wedge of the plane will have to get wider as well. You will want the wedge to be slightly larger – maybe 3/64″ – 1/16″ (around 1 to 2 mm) – than the tang of the iron. This will help to make sure you can adjust the iron side to side in the mouth of the plane if necessary. That should help you figure out the width of the wedge mortise and the thickness of the wedge itself.

      The grip should be around 3 times wider than the wedge, but I wouldn’t let the walls of the wedge mortise get any smaller than around 1/8″ (around 3 to 4 mm). If the outsides got to be any smaller, then the wedge mortise might fail. As the planes get larger, you don’t need as much extra width to the grip. Around 1/4″ (about 6 mm) on each side of the wedge should be more than enough. You want to make sure the grip doesn’t get too wide and become uncomfortable to use.

      I hope this helps. Please let me know if you have any other questions.


    2. Salko Safic

      The USA is a land of plenty to satisfy everyones desires, Europe and Australia decides to limit products available to its people and while Australia hasn’t introduced a fee for imports yet, Europe has, and it keeps Europe’s money circulating with in its borders. Instead of adopting the mindset of the US they would rather force you to adopt the products they want you to have. But they forgot one thing, we are craftsman and even if we were not man will always devise a work around and build it for himself. I am forced to pay ridiculous money to import O1 tool steel which is a crying shame, especially that woodworking has become fasting growing hobby in the world. Which is another crying shame, once upon a time it was considered a trade, a means to earn a living but just like horses used to be the only mode of transport is nothing a hobby and an expensive hobby which I might add so is woodworking.


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