Mike King
03-23-2019, 1:54 PM
Last fall, I started a set of chairs at Anderson Ranch in a 3 week intensive workshop with Adrian Ferrazzuti. What a wonderful experience! I had made only one chair before, a contemporary Windsor style chair that I made in an Anderson Ranch workshop led by Eliah Bizzarri. The chair I started with Adrian involved comparing steam bending and glue lamination of the legs as well as a coopered seat and back.
For the back, Adrian allowed me to experiment fairing the back with his Krenov-style coopering plane. It worked very well for the interior of the back, which has a curve based on a 15 inch radius. So, with only one back complete and the workshop over, I needed to acquire a coopering plane of my own.
I started with buying a round-bottom plane iron and chip breaker from Ron Hock. Ron also sells plans for making a Krenov-style round bottom plan, so I bought that as well. I followed the plans, and they recommended reading the section on making planes from Krenov's The Fine Art of Cabinetmaking, so I found a used copy cheap even though the book was in pristine condition.
I had a block of ebony that I could use for the body of the plane, although it appeared that the sides might wind up being a bit thinner than in Hock's plans. I emailed Adrian to get his advice, and he thought that my dimensions, though thinner than suggested by Hock, would be fine, so I proceeded to mill and glue up the parts. Hock suggests using a mouth insert that is shaped in the final stages of the assembly process. For the sole, I had some remnants of East Indian Rosewood that I used. I turned a piece of cherry for the cross piece and followed the layout on the plan as best I could.
But there was a problem. Because I was religiously following the plan, I did not allow quite enough room between the cross piece and the plane iron. The wedge was super thin. So, looking at Krenov's pictures of planes, I realized that many of his cross pieces were not round, but triangular in shape. So, I wedged the cross piece so it would not rotate, checked the tops of the side pieces of the plane to see that they were actually coplanar, and pulled out my router plane to cut a flat in the cross piece. Voilla! Enough clearance, and it appeared that the flat was coplanar with the ramp for the iron.
Next, I started rounding the bottom of the plane with little regard to the ultimate radius it would need to assume. I figured I'd just round it until the iron was properly revealed. But I soon realized that the mouth was perhaps going to be too short as the front block seemed to overlap the iron when it was at the level of the sole. I realized that if I took more off of the bottom, the plane iron when adjusted for cutting, would move back. But I was concerned about how much might need to be removed, and how to actually shape the mouth insert.
Much stewing. I decided to let it sit for a while. I filed the mouth insert to fit the front and sides tightly. Then I looked more carefully at the plans, and saw that the bottom should be curved to a 9" radius. This was not in the instructions, but was visible on the plan. I flattened the sole, made a template for a 9" radius, and got to work with my jack plane.
The result looked promising. So I placed the mouth insert in it's mortise in the sole of the plane and advanced the plane iron so it was just touching the insert. I then traced the plane iron's shape onto the inside of the mouth insert. I roughed out the shape on my edge sander and tested the shape against the iron. There were no instructions in the Hock plan or in Krenov's book on how to get this shape onto the mouth insert, but my method seemed to work relatively well.
I glued the result shape up and shaped the mouth insert, which was proud of the sole of the plane, to be the correct shape.
One thing I found was that the distance between the front and back ramps is critical. I think I might have made mine a bit too narrow, but I was able to file the front ramp back so that it did not overhang the mouth insert.
In any case, here's a few photos of the resulting plane. I'm pretty pleased with it. Making another would be much easier -- it's amazing how it takes working through the issues once to ease the whole process...
For the back, Adrian allowed me to experiment fairing the back with his Krenov-style coopering plane. It worked very well for the interior of the back, which has a curve based on a 15 inch radius. So, with only one back complete and the workshop over, I needed to acquire a coopering plane of my own.
I started with buying a round-bottom plane iron and chip breaker from Ron Hock. Ron also sells plans for making a Krenov-style round bottom plan, so I bought that as well. I followed the plans, and they recommended reading the section on making planes from Krenov's The Fine Art of Cabinetmaking, so I found a used copy cheap even though the book was in pristine condition.
I had a block of ebony that I could use for the body of the plane, although it appeared that the sides might wind up being a bit thinner than in Hock's plans. I emailed Adrian to get his advice, and he thought that my dimensions, though thinner than suggested by Hock, would be fine, so I proceeded to mill and glue up the parts. Hock suggests using a mouth insert that is shaped in the final stages of the assembly process. For the sole, I had some remnants of East Indian Rosewood that I used. I turned a piece of cherry for the cross piece and followed the layout on the plan as best I could.
But there was a problem. Because I was religiously following the plan, I did not allow quite enough room between the cross piece and the plane iron. The wedge was super thin. So, looking at Krenov's pictures of planes, I realized that many of his cross pieces were not round, but triangular in shape. So, I wedged the cross piece so it would not rotate, checked the tops of the side pieces of the plane to see that they were actually coplanar, and pulled out my router plane to cut a flat in the cross piece. Voilla! Enough clearance, and it appeared that the flat was coplanar with the ramp for the iron.
Next, I started rounding the bottom of the plane with little regard to the ultimate radius it would need to assume. I figured I'd just round it until the iron was properly revealed. But I soon realized that the mouth was perhaps going to be too short as the front block seemed to overlap the iron when it was at the level of the sole. I realized that if I took more off of the bottom, the plane iron when adjusted for cutting, would move back. But I was concerned about how much might need to be removed, and how to actually shape the mouth insert.
Much stewing. I decided to let it sit for a while. I filed the mouth insert to fit the front and sides tightly. Then I looked more carefully at the plans, and saw that the bottom should be curved to a 9" radius. This was not in the instructions, but was visible on the plan. I flattened the sole, made a template for a 9" radius, and got to work with my jack plane.
The result looked promising. So I placed the mouth insert in it's mortise in the sole of the plane and advanced the plane iron so it was just touching the insert. I then traced the plane iron's shape onto the inside of the mouth insert. I roughed out the shape on my edge sander and tested the shape against the iron. There were no instructions in the Hock plan or in Krenov's book on how to get this shape onto the mouth insert, but my method seemed to work relatively well.
I glued the result shape up and shaped the mouth insert, which was proud of the sole of the plane, to be the correct shape.
One thing I found was that the distance between the front and back ramps is critical. I think I might have made mine a bit too narrow, but I was able to file the front ramp back so that it did not overhang the mouth insert.
In any case, here's a few photos of the resulting plane. I'm pretty pleased with it. Making another would be much easier -- it's amazing how it takes working through the issues once to ease the whole process...