Building a Traditional Coffin Smoother


Building a Coffin Smoother using traditional methods...

I go through the steps I took in building this:

Follow the links below:

Building a Traditional Coffin Smoother

I've been meaning to build myself a traditional smoother, and while I was going to wait until other projects were completed, but decided I would forego some other projects and give it a whirl now.  The photo below is what I'm building on the next several pages - be warned, I tend to write in a "stream of consciousness" style, so forgive any rambling that might occur.
The plane built on these pages reflect closely a classic coffin smoother documented in an instructional pamphlet  titled "How to Make Wooden Planes", authored by David G. Perch and Leonard G. Lee (of Lee Valley and Veritas Fame).  Unfortunately this pamphlet is no longer available (inserted edit - Garrett Wade might have a few copies left).  Another good text on building wooden planes where a similar plane is constructed is John Whelan's excellent book "Making Traditional Wooden Planes", available from the Astragal Press.
David Perch has authored another book along with Robert Lee which might interest the reader, titled "Wooden Planes and How to Make Them", available through Lee Valley.  I've not read it myself, but it' my understanding it is a well written book.
Note: Notes formatted in this fashion were made later. in hindsight when I had a chance to reflect back on what had gone right or wrong.  I thought it would serve both myself and anyone else reading this better to learn from my mistakes and comment on them, than just to pass over them.  This seems like the easiest way to accomplish that.
I am assuming, with this documentation, that you the reader is familiar with the shape of the opening to be cut into the plane if you are interested in making one yourself.  If not, the shape is common to most wooden planes, and should be studied first hand before attempting your own.  But if there is one thing I have learned about woodworking, it's to jump in with both feet, and not be afraid of making a mistake.  The worst that can happen is you end up with some heavily worked firewood, but even that would have to include the learning and experience acquired during it's execution.  
Also remember, I am no "expert" (easily seen in the forthcoming work)- these are just my experiences in building this plane.
Collecting the Material and Preparing the Blank
The first thing I dug up in preparation for this little project was a double iron from a Stanley Handyman #4 size plane.  I've never been too happy with that old plane, but always figured I could use the iron for a project like this. 
Note:  The iron mentioned here did not end up being the iron I used for this plane.  This is because they proved to be quite worthless in the end, and it ended up being a mistake to use it here because of its low quality, and have now proved to myself why I was never happy with that particular plane.  But more on that later.
Next was to find some wood for the wedge. I found a blank of walnut about 2" x 6" that was perfect - contrasted with the maple and was a bit softer - just the right thing for it.
Next was to find a suitable block of wood for the body.  I had nothing on hand of substantial thickness, and as it was my purpose to spend absolutely nothing to build this smoother, I dug up some scraps of hard maple I had on hand, and glued them together to make a block of the proper depth. I then squared the block to 2-1/2" square and 8" in length.  I tried to orient the grain while gluing up the blanks and consequently while marking out the plane so the outer portion of the tree was to the bottom, and so the grain dived towards the back of the plane.
I mark the plane T for top, S for side, making sure to check for optimum grain direction.  I then scribe a line 3" back from the front of the block, followed by a line at 50 degrees to mark out the bed of the iron.  I then place the assembled iron against this line to determine the base line of the wedge that will be fit later:
Note:  It is very important that you make the marks telling you the side from the top and front from back.  This was actually the latest round of mark making on the blank because I caught myself doing it backwards...  Twice.  First I had the side on top - then the back at the front.  WHAT A PUTZ!  
As the wedge will be made at an angle of 12-1/2 degrees, this line is added to the blank using an angle printed out from a cad program on a piece of paper, then cut out to make it easier to mark out:
A similar one could be drawn out on a piece of paper using a simple compass.  To be most effective, the point of the wedge should end up about half way between the hump of the chip breaker and the bottom of the plane, which is why it the point does not quite reach the bottom in the picture above..

Preparing the Blank


Preparing the Blank cont'd.

The front of the mouth is drawn on the bottom of the plane 3/8" in front of the line drawn previously at 3" - in other words, at 2-5/8". 

Note:  Now that I'm done building it, I can see this was a mistake to make the mouth quite this wide.  Doing it again, I would simply continue the line made from the front line of the iron assembly, something closer to 1/4".

The front of the mouth is drawn at 75 degrees, and is carried to 1-1/8" above the bottom, where it intersects a 55 degree line that defines the front of the opening in the plane:

These lines are carried across the top of the plane, where they define the opening to be cut in the body of the plane, shown marked out by pencil.  The outside parallel lines are the width of the iron plus 1/16",  and define the outside edge of the wedge pocket.  The inside lines are 1/4" inside of each outside line and define the inside edge of the wedge pocket.  The wedge will register against these when installed.

To try make it easier to envision the final shape of the opening, I drew up this diagram that shows a cutaway view of a smoother next to a complete one:

Notice how there are several angles that need to be worked within the opening, which can be hard to keep straight in your head - I'll refer to this diagram again.


To prevent tear out when the chisel begins to reach the bottom of the pocket, I remove about an 1/8" of material from the mouth on the bottom of the plane.  I try to stay within the finished line of the mouth, and am extremely careful to only remove material at an angle that does not interfere with the design of the mouth, as shown by the angled lines drawn on the side of the plane.

I then turn the blank over again and remove a large portion of the material through some rapid chopping with a bench chisel, again being careful to stay well within the lines drawn out previously:

Don't worry, I'll clean it up in just a bit.  The object here is just to remove as much material as quickly as possible - I'm simply getting the biggest portion of the material out of my way.


Finishing up the mortising

Having removed as much material as I dare, as quickly as I can, it's time now to clean up the mortise and start to define it with some light tapping and paring:

I try to always keep an eye on the angles drawn on the side.  Some use a jig such as a board cut at the proper angle - I just freehand it.  The next picture gives a better idea of what I'm talking about, and starts showing the change in angle at the front of the mouth, which will lead me shortly to the shallow mortise made previously on the bottom of the plane.  I also make sure to leave between 1/32" and 1/16" that will be smoothed out later.

Success! Here is where I start breaking through to the mortise made underneath earlier:

Before attempting to chop out the mortise wedge, a couple of saw cuts help to define the front and back of the pocket, and reduce tear out while chiseling it out.

I used a razor saw - specifically a "Zona" saw for these cuts, and was wholly unsatisfied with it.  I have a cheap compass saw that cost something like $4.25 - but I might as well have tried cutting it with a butter knife.  Ack, the garbage they sell nowadays.  I think the best solution, though I don't have one, might be a flush cutting saw.  Actually, I've got an old saw that's lived past its useable lifetime - it might make for a good keyhole saw that would...  oh, that's another project.  Carry on...


Cleaning Up the Pocket

Finishing up the mortising

Having removed as much material as I dare, as quickly as I can, it's time now to clean up the mortise and start to define the edges of the openings as they were drawn on the side.  The two floats I made are starting to really prove their worth here.

When I get the opening to a satisfactory finish, I mark out the ears where they widen to make it easier to pull out shavings, then start carving them out.  I had to watch out for tear out here (the maple I chose was in the scrap pile for a reason) so you can see how I did it to avoid that here:

I then finished it up using the bed float to get it smooth.  For all surfaces, I leave some final finishing for later (like 1/32" to 1/16" left to finished height), not wanting to take too much off.  It's easier to take more wood off than it is to put the wood back on...  But I take the sides of the wedge pocket to finish depth, as that's what I'm doing next, and the wedge and iron need to fit to finish the plane.  Let's refer back to that diagram from a couple pages ago and make sure I'm shaping it correctly:

Notice the portion in front of the wedge pocket where it widens the "ear" to the same width as the mouth - can't forget to do that little bit, and now's the time!  I accomplished it here with a bed float.

Slotting  for the Chipbreaker's Nut

The next step is to mark out the pocket that will accept the nut that holds the chipbreaker to the iron. I marked it at the point where the bottom of the chipbreaker was just sticking out below the mouth of the plane.  Then, using a forstner bit that was about 1/8" larger than the nut, drilled a hole to about 1/8" deeper than the nut.  Using some chisels, I then extended the slot upwards to the top of the body.

 Note:  I ended up extending the slot about 1/4" further down to fit a different iron assembly.  More on that later.

You can see the end result in the inset photo above.  Next, it's on to the wedge.

Making the Wedge

Making the Wedge

For contrast, for a wood that isn't as hard as the wood used in the body of the plane, and because I had some - I chose a piece of walnut to make the wedge.  It should be 5/8" thick, 6" long, and about the same width as the opening, so you can plane it down to fit.  I started by marking it out with the same paper I used to mark it out on the side of the plane, then roughed in the angle on the bandsaw, staying about 1/8" proud of the line.  That allows me to bring it to final depth with my trusty old block plane, a lowly Stanley 220 (it was the first plane I ever owned, bought it new over 20 years ago):

I test fit the wedge in the opening with the iron in place to make sure I'm getting the angle right, and that the shoulders in the plane are even as well:

I then mark half the depth of the angle portion of the wedge and cut out  the center of the  wedge, leaving about 1/4" on each side. 

After chopping off most of the waste with a chisel, I use rasps and files to file out the remaining portion of the center of the wedge so it forms an angle twice as steep as the rest of the wedge or about 25 degrees next to the 12 1/2 degrees of the two "tongues":

This is a design feature that allows greater room for the shavings to escape that's been done on these old woodies since long ago.  Without it, the shavings would pile up in the bottom of the mouth and clog it up.  I then chamfer the top of the wedge, cutting about a 1/4" x 3/4" chamfer off of the top.  Then, using a wood file, I chamfer the ends of the "tongues".   The best way to show it might be a diagram, so here's one of the wedges final dimensions:

These are starting dimensions for the wedge - the finished dimension may change when tuning the plane for performance.  Next, Ill do the final fit of the wedge into the plane, and dress it up a bit.

The Finishing Touches

The First Finishing Touches, or Will the Craftsman Win Out?

Now, I'm starting to get something that resembles a plane:

Now's the time to do any tune up, to get it working as good as possible.  I didn't do that here - I should have, but now I was too close to seeing a finished product to worry about if it worked well or not.  Plus, I was in way too much of a rush - you can see if you look closely, there is some grease on the front of the plane.  It seems the mower decided it didn't want to start this day, like I'd hoped, so my shop time for the day was cut in half.  In interest of saving some time, I decided to forego the fitting and just make a run straight for the end zone.  Ack, what a dummy I can be, as these pages will soon bear out.  In any case, I can tell you now that working on a wooden plane in short, heated spurts between battling a craftsman riding lawn mower for world dominance is not the greatest recipe for success.  Success did finally come, but only at the cost of some humility.  Oh, yes - and some gasoline to replace what went bad in the can.  And a couple of sodas to wash that lovely taste out, after having to siphon the bad gas out of the mowers tank...  but I'm getting off track, here.

First, it was time to rough out the final shape of the plane to that of a "coffin" smoother.  To do this, I just marked a point 1/4" in at the toe, and 3/8" in from the heel like in the diagram below:

Then, using a 6" steel ruler, I bent an approximate shape as shown above and marked it with a pencil.  Over at the bandsaw, I cut it out, staying proud of the line by about an 1/8".  I didn't want to thin out the walls of the mortise too much, so I simply avoided them.  Then, to smooth it out, I took a belt sander on it's side after it:

I actually built a jig for this belt sander (another Craftsman - what wonderful tools - I'm just so happy with them can't you tell?) so that I can use it more like a stationary tool - but alas, the price one pays for having a small shop means jigs such as that are stuck way up behind and under fourteen other things... oh,  I'm wandering off subject again.  Fortunately, this one has a pretty flat side to rest on the bench that's close enough to perpendicular to actually work. 


Once I get the shape I want, I round all of the outside corners of the plane that are rounded off, and make a few other cosmetic touches.

Note:  Here is a good place to stop and tune the plane, before the cosmetic touches are added.  I know I said it before, above - I just want to make sure I drive this point home.

Everything below the notch made in the side is left square.

Next, I'll talk about tuning the thing, what I should have done before the mad rush to the end...  Have I made clear the point about how I shouldn't have rushed through this part, yet?  Do I seem repetitious about it?  Am I annoying anyone with it yet?

Tuning the Plane


Tuning the plane

Now, I had the plane complete - but it wouldn't work worth squat. The iron wouldn't stay in place like it should, and as a result I couldn't get it to work decently at all.  My rushing at the last minute, combined with the euphoria created from winning the battle of Ragnarok with the riding lawn mower had done it's damage.  It was time to do some diagnostics and some tuning.

First thing I noticed was the iron was sharpened just a bit off of perpendicular. Not enough for me to notice by eye, but put a square to it, and it was obvious. I had sharpened this iron by hand a long time ago, and the plane it came out of had enough adjustment to make up for its off-kiltered sharpening, but not this one. I had noticed I needed to keep knocking the side to get it to line up, and it would go, but I think this was loosening the grip just enough on one side of the wedge to be an issue. Then, I re-trued the shoulder the wedge fits against - turned out that one side was just a tad higher than the other - not much, but enough so the pressure the wedge would exert on the iron was just a little less on one side that the other - this is more of a problem when combined with the previous one.

Then, I added a bit more "spring" to the chipbreaker. Now I could get the plane to hold its set better, but it was still a bit difficult to get it to plane evenly. I also noticed I had made the wedge too long. It was going over the hump of the chip breaker too far and serving as a catch point for shavings - they would build up in a corner of the mouth and force the iron up after a while.

Next, I stuck the iron in the plane with its nice new sharpening, held the plane up to the light and pulled the iron back, looking to see light coming from between the iron and the bed. I noticed I had just the *slightest* crown in the center of the bed for the iron, about 1/4" - 1/2" up from the mouth. It would have been better had it been the opposite, with a slight dip in the center rather than a hump - as now it actually has to bend the iron slightly across it's width (just barely - but enough when in combination with the other factors that it wouldn't hold it's set). It would have been handy to have a bed float that was about 3/4" to 1" wide for its full length - it was the pointed bed float that got me into trouble here. That one is really better for doing the sides of the iron pocket rather than the bed itself. When I made those, I was thinking of a side escapement or molding plane, not a smoother, and then decided to do a smoother first. Typical process for me, there.  But - the bed for the iron needs to be dead flat:

Now I had the plane so it would pull shavings off easily and not go out of adjustment - but the mouth would plug up almost immediately with shavings, especially at the sides.  I puzzled over this for the longest time, and tried re-shaping the bottom of the wedge, smoothing the opening of the mouth  at the sides just a bit - nothing worked.  I almost gave up, when I decided to try a different iron assembly in the plane.  So I grabbed a #4 Bailey I have (one of my favorites),  robbed the iron and chipbreaker out of it and stuck it in this plane.  WHOOSH!  Shaving after shaving of wood flying out of the mouth, all paper thin, and no clogging!

All that time messing with trying to get this thing working right and it was mostly the iron assembly out of that cheap old Stanley Handyman that was giving me the headaches.  SHEESH, what a dummy.  Should have known better.

Anyhow -  two or three coats of boiled linseed oil and it's finished.

Final Thoughts

One thing that is wrong with this plane is the size of the mouth.  I won't start with a 3/8" opening next time - that's just too big.  When I draw in the front of the iron, that will be the front of the mouth, which would be closer to 1/4" rather than 3/8".

I'll tell you what - this has been a real learning experience, and absolutely tons of fun. What a great challenge!  I would recommend making a wooden smoother like this one to anyone interested in wooden planes. Making this quickie as a trial first has shown me a lot of what to look out for, and what to do better on the next - and tons of respect for planemakers of old.

Added 7/12/04 - Because I have been asked quite a bit about the iron assembly I used for this plane - I will add here that I would not again attempt to build a wooden plane and use an iron assembly from a Bailey style plane.  I would search out the iron from an old wooden plane first instead of that style ( with the possible exception of a Lie-Nielsen aftermarket style assembly).  I might also consider using a single iron made from 1/4" tool steel, with no chipbreaker - similar to Clark & William's approach.  
While the plane in this article does work, it would have saved me a lot of hassle had I went this route rather than try the bailey iron.  The plane built in this article was done as a prototype - to see what was involved, so in that regards, it was successful - but as a user...  it could be better, as the curved portion of the chipbreaker does not lend itself to easy adjustment in this style of plane.
I've finished another smoothing plane that, if you've read this all the way to the end, might interest you...  You can find documentation on it here.

I hope you've found this interesting, and of some worth.  Thanks for reading!