Introduction

The 57 acres that comprise Cedar Ridge Farm are located in the beautiful rolling hills of South Central Kentucky. My wife, our four children, and I are on a homesteading adventure as we work toward increased self-sufficiency. We grow much of our own food and enjoy being in touch with the agrarian roots of our lives.

One of the major projects we have undertaken is the building of our own home. The house we're building has three major distinguishing features: 1. we're building it without incurring any debt; 2. it is a timber frame structure; and 3. the exterior walls will be plastered straw bales. We live debt and mortgage free, and building our house with that approach makes perfect sense. Large timbers in a home possess a beauty and project a sense of strength, stability, and warmth that we want in our home. Straw bale walls provide insulation and make ecological sense. This blog is a record of our home-building project.

Saturday, July 7, 2007

Figuring out how to cut a dove tail tenon for the floor joists

As I worked on the braces, I gave some thought to one of the next steps in the project: cutting the dove tailed tenons on the ends of the floor joists and purlins. Cutting the mortises for these tenons wasn't too difficult, but I hadn't given much thought to how to cut the tenons. I just knew that I would do so at some point.

The floor joists and the purlins will all be 4"x6" oak. One of the features I want to incorporate is an arc from the tenon into and toward the bottom of the joist/purlin. It will provide a nice aesthetic touch and should help mitigate some of the potential weakening caused by checking as the wood dries. As I considered my intentions, it became clear that I didn't have the right tools for this job. It seemed that a band saw would be a good choice, but a stationary one would present some challenges when working with 12 foot long pieces of oak that weigh 100 pounds or more (depending on how much they've dried while in storage).

Several companies make a portable band saw. Generally, these are used for cutting metal. Apparently, they do a pretty good job of that when equipped with the right band saw blade. I thought that if I had the right blade, this would be a good tool for my purposes. So, I searched on Ebay for one. I didn't want to spend the $260 or more that a new one costs. I eventually won an auction for a used Porter Cable portable band saw. I ordered some 6 tooth per inch blades from MK Morse. After receiving the saw and the blades, I had to try it out.

I marked the dovetail and a shallow arc on the end of a short piece of 4"x6" oak that I had in the shop. I then tried to cut it out. When I was done, there was a dove tail tenon on the end of the timber, but the cuts were a bit crooked and wavy. I marked the other end and tried again. Then, I chopped off the first end and tried a third time. By paying careful attention to the orientation of the saw and making sure I stay on the lines on both sides, I was able to cut out a decent dove tail tenon. I'll practice a bit more before I begin on the 100 joists and purlins that I'll need for the frame. But, at least it looks like my idea will work.

2 comments:

Anna said...

Hi Darryl,

I just read your introduction and am thrilled by the fact that you're going to use straw bales for the walls. Straw is a great choice and I'd really like to encourage you (just in case you should need any encouragement ;):

The walls in our house (16th century) consist of a mixture of clay and straw, plastered with clay. And these walls definitely provide the best "house-climate" I've ever experienced!

Which material are you going to use for plastering?

dp said...

I've wanted to have straw bale walls in the house for quite a few years for a variety of reasons. I appreciate your encouragement.

I'm planning on using a clay plaster on the bales. The interior will have three coats or so with the final one using a white clay. The exterior will have a good coat and then a wood shingle siding with an air gap between the plaster and the wood.