Making a Plow Plane


oldwolf

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First off I would like to confess I have had plow plane envy for quite a while. I want one, infact I want a wooden one. I am just too chicken to buy a wooden one off eBay and I have yet to find a decent one for a reasonable price around the antique stores and flea market opportunities around me. I have picked up a couple blades to use in such a beauty but alas she is still missing from my life. Thus I come to my desperate plan. . . I intend to build my own plow plane from scratch. I have the materials and a good idea of how I'm going to go about it, the thing I'm lacking is some of the specifics, I was hoping you guys out there could help with things like the proper angles involved in the mouth of the plane,

Thank you

Oldwolf

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Here are two good reference books: The Wooden Plane, Its History, Form, and Function, by John M. Whelan; and Wooden Plow Planes, A Celebration of the Planemaker's Art, by Donal Rosebrook & Dennis Fisher.

The first one gives you dimensions and line drawings (no photos) of a number of different types of planes, including plows. The second one has loads of photos of plow planes. No dimensions, but you might be able to figure out measurements from the photos. It would at least give you lots of ideas for design.

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There's a lot going on in a plow plane and a lot of things to get right. The biggest difficulty is getting irons. The irons are difficult because they all have to be the same in several ways. They need to have the same overall width where they enter the body. They all have to be precisely the same thickness and taper for the wedge to fit properly. There's a vee groove cut in the back of the iron and these need to all be of the same size and same angles. The bottoms of the grooves also need to be the the same distance from the face of the iron.

Irons were never standardized in the past and they were drop forged. Drop forging dies wear quickly when forging hot steel and makers were generally working with several drop hammers at once so even irons from one drop hammer set-up were slightly different than those made on a different hammer and in different dies. What this means is that sets need to stay together and the irons aren't really interchangeable.

Old plows were made to fit a specific set of irons. One of the things involved in fitting the irons is to create a convex vee on the bed of the skate so that it exactly matches the vee of the back of the irons. This creates a machinists type of taper that gives the iron lateral stability. If this fit isn't right the irons will be prone to chatter.

Then we get to the hard part of the irons. If you look at the back of old ones you'll see that shortly after the tang and close to where the bit starts there's a slow elliptical curve that begins making the iron effectively thicker where the cutting edge bevel begins. What this curve does is make sure the vee grooves are completely housed to give maximum stability. We machine the irons we make instead of forging them. The problem is that milling machines are great for milling straight lines but curved lines are outside the realm of milling machines unless one starts looking at CNC. It took me a few years to figure out how to do this without CNC and, frankly, I'm not going to tell you how I do it. It likely doesn't matter because I doubt many are going to invest thousands in a milling machine and then equip the rest of a machine shop so they can build the fixtures.

Making the plow plane itself is a challenging project. I suggest you obtain a matched set of old irons before you start. Most of the "sets" of irons I've seen for sale are assembled sets, not matched sets. John Whelan's book on making wooden planes has some information on making plow planes. I'm not a fan of a lot of Whelan's techniques because he goes to elaborate lengths to do tasks with machines that are simple, easy and straight forward with hand tools.

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  • 2 weeks later...
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First off I would like to confess I have had plow plane envy for quite a while. I want one, infact I want a wooden one. I am just too chicken to buy a wooden one off eBay and I have yet to find a decent one for a reasonable price around the antique stores and flea market opportunities around me. I have picked up a couple blades to use in such a beauty but alas she is still missing from my life. Thus I come to my desperate plan. . . I intend to build my own plow plane from scratch. I have the materials and a good idea of how I'm going to go about it, the thing I'm lacking is some of the specifics, I was hoping you guys out there could help with things like the proper angles involved in the mouth of the plane,

Thank you

Oldwolf

Oldwolf, I posted a comment back on Sept. 3rd. Actually, just look above this post. Since then I have been able to check this book out of the library. It has “plans” to make a two fence arm plow plane starting on page 86. It also shows two variations of that plane (page 100 and 103). The first plane has all of the main instructions, and is called “The Bridle Plow”. The fence arms are not threaded. They use a clamping system to hold it in place after adjusting the distance of the fence from the body of the plane. The second two plow planes are the “Toted Plow” and the “Ebony Plow”. The fence arms are threaded on both of those. On page 96 they discuss threading the arms.

Please keep in mind that this book is not like having a set of plans like you would find for making a piece of furniture. It’s a lot of reading, and quite a few line drawings with dimensions on the drawings. I don’t know how much they assume you’ve read (or have done) prior to page 86, but if you have a genuine interest in making a plow plane then this may be the only way to do it. If you’re interested in the book, I would check your library to see if they have it. I don’t know how your library system works, but mine has a main library and many branch libraries. I went on line and did a search for the book title and found 2 copies available at the main library. I reserved it and had it transferred to a branch library close to my location.

The plow plane that I’m interested in is the center wheel plow plane which has a center arm that is threaded and a large wheel that turns the threaded arm, with the two fence arms being non-threaded. I’ve tried to find plans for this type of plow plane but have found nothing so far. I guess for now it’s the book or nothing as far as I’ve been able to find out.

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