Floor joists: step by step

In a previous post I discussed my ideas about how to cut a dovetail tenon and the arc I planned for the floor joists. At that point in time, all I had done was to try out my ideas with the portable band saw. Last Wednesday, August 15, Mark the Intern and I began putting my ideas into action on the floor joists. The frame has 33 first floor joists, 26 second floor joists, and 37 purlins. All of these are cut from 12 foot oak 4"x6"s. We started with the first floor joists since these wouldn't be seen. This gave us 33 to practice on. As I've mentioned earlier, we are only going to have one end completed before the raising. Once the frame is up, we can measure to make sure that the floor joists and purlins are the correct length. Some beams and rafters have a little bow to them and all the timbers' actual measurements don't correspond exactly with their nominal measurements.

Here are the steps we took for cutting the dovetail tenons and decorative arches on the joists and purlins:

First, we have the 4"x6"s in the garage on the saw horses. We worked with four at a time because this amount gave us enough room to move them around and work on them.

For the second-floor joists and the purlins, we planed the visible surfaces. We were able to run the two vertical sides through my 12" Powermatic planer, but because it can plane a 5" maximum thickness, we had to plane the bottom of each by hand. We didn't plane the first-floor joists because they won't be visible from inside the house. (Yes, that's me in the picture.)

After planing the joists/purlins, we marked and cut one end square. The other end will be cut square at the time it is finished. The next step was to mark the dovetail and the arc on the end using the templates I had previously made.

Once the end was marked, we cut the bottom of the tenon with the circular saw. We also cut across the bottom of the joist on the line next to the arc.

After making these two cuts with the circular saw, we knocked out the square at the bottom of the joist along the underside of the tenon and in front of the arc. The portable band saw doesn't have a deep enough throat to cut the arc without removing this block of wood.

Using the portable band saw, we next cut the arc. It's quite easy to cut this crooked until you get a feel for the saw as one side or the other cuts higher, lower, faster, or slower than the other side. It wasn't critical on the first-floor joists since they won't be seen. So, that gave us 33 to practice on.

After cutting the arc, we used the circular saw to cut the shoulders of the dovetail to the correct depth, and then we used the band saw to cut the angle from the corner to the shoulder.

After completing all these steps several times, we had a stack of floor joists ready for raising day.

Building the first bent

On Thursday of last week (7/26), Mark and I laid out the rafter set for the fourth bent and fit it together. We took our time, making sure that the mortises and tenons were properly sized and drilling holes for the pegs. We also needed to chisel the mortises on the tie beam for the rafter posts and the brace. I also needed to cut the birds mouth for the rafter foot on the front of the tie beam (I forgot to cut these when I completed the tie beams nearly 2.5 years ago). I didn't take any pictures, unfortunately.

Since my previous post in which I shared my raising ideas, I've changed my mind. We will not be raising the bents completely assembled to the rafters. I thought it would be simpler and safer to raise each bent completed to the tie beam. Then, after they are raised and attached together with connecting girts and braces, we can assemble and raise the rafter sets on top. I'll still use a gin pole, just not a 30' one. The raising may take longer, but safer and simpler is better.

On Friday morning (7/27), we began assembling the first bent. We laid out the three posts with their feet on the piers and the other ends supported on blocks (scraps from cutting the timbers to size). Things went pretty well. We made sure the mortises and tenons were properly sized. I've been amazed at how the mortises have shrunk over time. I expected they would enlarge.

I've been intending to draw bore all of the joints, but not all are to be done that way. We used a come-along to pull together the posts and some of the beams and then pegged. I decided to do it that way because of how tightly some of the joints fit together, and I didn't relish pulling it apart to drill the tenon. This photo is of the first pegs I've ever driven into a timber frame.

After the bottom beams were pegged, the front post had a pretty good twist visible at the top. It straightened out when we pulled the tie beam onto the tenon at the top of the post. It was pretty neat to watch it straighten out. The other end of the scarfed tie beam over the back post was twisted. It wouldn't straighten out. So, there's a bit of a gap between it and the post on one side. I don't think it'll matter any though.

Here are some photos of the assembled bent.

It was neat to see this piece of the house come together. We'll tackle the next bent tomorrow morning.

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.

Note-taking during the project

Building a house is a big project. I've tackled the job from conception to finish, and because of finances, I'm not paying someone else to do my thinking and planning for me. Just the timber framing aspect is a large undertaking, as I designed the frame and am completing all the joinery on my own. I'll also be directing the raising of the frame. In light of the immensity of the project, I knew that I needed to keep some notes as things progressed. There are a lot of things that I could potentially forget. So, I have a framing notebook in which to keep my notes all in one place. It may not be the best organized notebook, but it seems to serve my purposes.

When I first began the joinery, I didn't have the notion or the space to lay out all of the timbers I bought to determine where they each would go. I could've chosen which post timbers were to be which post, which beam timbers were to be which beam, etc. But, I didn't. I didn't even think about doing that. I began with the timber on the top of the pile and called it whatever I had in mind to work on next. I did have a method, completing the beams first, then the girts, then the posts, the rafters, the braces, and then floor joists and purlins. I kept notes on the timbers as I progressed.

I also made an assumption that I didn't realize until later wasn't true. I assumed that the timbers I had ordered to be 8"x8" were actually 8"x8" and that the timbers I ordered to be 6"x8" were actually that, 6"x8". they were close, usually, but few were actually as I had assumed. There were timbers that were 7-3/4" at one end and 7-1/2" at the other, or ones that were 8" at one end and 7-1/2" at the other. There were some that were consistent from one end to the other, and some that were truly the dimensions I assumed they would be.

When I realized that my timbers were only nominally sized, I knew that I needed to clearly record their measurements to help assure some degree of levelness for my floors. There are different approaches to timber framing, like scribe rule and square rule. I've worked with a modified square rule approach, meaning I've done what made sense to me. If I had known that the timbers were not truly sized, I would've done some things differently. But, I didn't, so I didn't. I cut the tenons on the ends of the beams and girts to the full depth of the timbers, whatever they were. I then noted the depth for each end for each timber. This allowed me to make sure the mortises on the posts were the right size and placed so that the floors would be level, not varying by up to 3/4" from one post to another. My reference point for each mortise was the side of the beam or girt that mattered, generally the floor side.

I've kept notes of other things, like spacing and location for floor joists and roof purlins. I've also noted the size, shape, and location of tenons and mortises. This has been important since the beams, girts, and posts have been completed with varying amounts of time in between, literally months or over a year for some of them. We'll see how well it all goes together. I suppose that will be the real test of my note taking.

Full Frame Fit-Up Has Begun

Last week, I was able to begin the full frame fit-up. We moved the beams and posts to a pile near the house site, organizing them for easy access. It became apparent that I would need to replace some of them because they twisted beyond the point of usability. Two 8x8 twisted and four 6x8s. I also discovered that I had cut one post 4 inches too short. I guess I forgot to measure twice and cut once on that one.

Since I needed to replace these timbers, I called Cub Run Hardwoods and had them cut me some replacements. I also had them cut 20 more 12' 4"x6"s for my floor joists and purlins. I'll need about 100 of them, which I have, but some of them will need to be culled because of various factors, including twisting while drying over the last two years. We hauled all of these timbers home on the trailer last Thursday. Being all green oak, the load weighed about 6,000 pounds. I forgot to take a picture of them stacked on the trailer to share here.

We (we is myself and the intern we have here this summer -- he's learning about homesteading in exchange for labor) worked two days on fitting-up last week. We started with the front wall of the house, making sure the braces and girts fit in the posts and that they are square. It went pretty well, actually.

This photo shows the front wall of the frame as we laid it out, minus the first post which you can't see in the picture. we laid things out on the foundation piers for the house, using 2x6s with support in the middle between them. I have to replace the two bottom girts for bays 1 and 3. That's why they are not present in the photo. I'll fit them up in their respective places this week after I remake them. There are two cedar girts in the middle bay, but only one will be visible from inside the house. The girts at the bottom of the posts will be below floor level.


Here's another view looking at the third post (counting from the left in the pictures). The lower portion of the posts from the mortises on down will not be visible from inside the house. So, they aren't planed. In the background you can see part of our garden.

We drilled the holes for pegging the frame as part of the fit-up process. I'll be draw-boring the joints.

The next day we fit-up the posts and girts for the center of the house. Tomorrow or the next day, we'll do the fit-up for the back wall of the frame. I want to complete the girt that needs to be replaced for that wall first. I'll take some more pictures and share them here.

Tools for Framing

Tools to do the job are important. After making the decision to build a timber frame house in which I would be doing all of the framing, I knew I would need some tools. One of the first things I could think of that was needed was a chisel. Well, actually, more than one chisel. I would need at least two: a 2" framing chisel and a 1.5" framing chisel. I also thought it would be nice to have a corner chisel. If you are unaware of the prices for good framing chisels, you ought to look sometime. These aren't your hardware or building supply store chisels. They not only have a much wider edge than regular wood chisels, they are much longer overall. They are also built heavier. They are made to do a big job.

My desire for good tools had to be tempered with the amount of money I was spending. There is no loan or credit card money fueling any of this project. I wanted good tools, and I wanted to keep it affordable (a loosely defined term associated with my aversion to spending money). So, I did what anyone familiar with the internet would do: I searched for chisels on Ebay! And, I found what I was looking for.

I bought three chisels: a 2", a 1.5", and a 1" corner chisel. There were a lot offered on Ebay, and I chose these three for a variety of reasons, all of which I don't remember now. The 2" chisel was listed as a slick. It's a Robert Sorby non-beveled edge chisel. It's the one I use the most. It has a nice length and nice weight to it. It's very well built, as far as I'm concerned. I use it with a mallet (like the one in the photo) or as a slick without the mallet. I have no idea about the maker of the corner chisel. It is nice for cleaning up the corners of a mortise. The 1.5" chisel is a Keen Cutter, about 13 inches long. Or, rather, it was about 13 inches long until Wednesday of this week. It suffered a major catastrophe, as the picture to the left shows. I don't know the age of this chisel or what its life experiences have been, but other than a little pitting in a few places, it seemed to be in good shape. It snapped cleanly about two inches from the cutting edge while I was using it to clean out a mortise. It didn't seem to be under any great stress, but it's broken now, nonetheless. I've already purchased another 1.5" chisel off of Ebay that ought to arrive next week sometime.

All of my chisels needed sharpened when I received them. They also occasionally need the edge touched up as I use them. I bought a sharpening jig into which the chisel can be locked that allows it to be held at the appropriate angle when sharpening it. I suppose I could sharpen them freehand, but it is a lot more consistent with the jig holding them at the correct angle. I sharpen them on wet/dry automotive sandpaper on a flat surface. I start with 180 grit, move to 300 grit, then 600, then 1200, and finish on 2500 grit. This sharpening applies to the flat chisels, not the corner chisel. I sharpened it once after I received it, taking out the angle on the edge to which it had been honed. I used a bastard mill file to sharpen it. It's much more of a challenge getting the two bevels on it clear into the corner.

In order to cut the beams accurately, I needed a dependable saw. I have an old circular saw that I've used for cutting wood, metal, and masonry materials during the last 16 years, but it has enough wobble in the blade that I didn't want to use it for the framing work I had to do. I wanted something accurate. Sure, a Beam Boss or another circular saw that could cut deeper than a regular 7-1/4" one would be nice, but money was a deterrent once again. So, I ended up buying a new Makita Hypoid saw. It has 15 amps and has done everything I've asked it to do. I just don't expect to cut all the way through an 8x8 or 6x8 or 4x6 in one cut.

Pictured with the saw is a high torque right angle drill. This is a Harbor Freight knock-off of the Milwaukee Hole Hawg. I didn't buy it from Harbor Freight -- I saved money by buying it from a place that sells Harbor Freight returns. It has one thing wrong with it -- the high speed doesn't work. That doesn't matter to me, because I bought it to use it's low speed, high torque setting. I use it for boring 2" and 1.5" holes with the Dewalt self-feed bits I purchased. These bits have been great because they remove a lot of material, but they put a lot of strain on the drill being used, especially the 2" bit. Before I bought the high-torque drill, I used a 9 amp Hitachi. It had a difficult time, and I had to keep giving it time to cool off between uses. I did end up burning out the brake on it. The drill I use for boring now powers on through knots and dry oak as long as the bits are sharp.

Here is an example of how I use the 2" bit to bore out material for a dovetail mortise. It removes a lot of wood. I then clean out the mortise with a chisel.

Since my hypoid saw is unable to cut all the way through one of the timbers, I have to finish cuts with a hand saw. If it's an end that needs squared up, I cut on all four sides with the Makita and then finish it with a crosscut saw I bought for $5 at a yard sale a few years ago. It's kerf is wider than the carbide-tipped blade in the circular saw, so I have to cut twice so that the crosscut saw won't get caught in the thinner kerf.

The smaller saw in this picture is a rip saw that belonged to my grandfather. I use it occasionally, but I've found ripping to be terribly slow. I think the crosscut saw rips faster than the rip saw.

When I started the joinery on the first timber in March of 2005, I attempted to plane it to furniture smoothness. That took a lot of planing. I bought a small 3.25" planer to help in this regard, but it has to move a lot of material to get rid of all the saw marks from when the timbers were milled. My wife and I decided that having the saw marks in the timbers doesn't detract from their looks. I still plane to smooth the timbers and take out a good bit of the saw marks. I've done a lot of the planing just with the two hand planes pictured here.

The other tools that I am using for this project are a 25' tape measure, a combination square, and a framing square. I've also made templates for some of the joints that are cut more than a couple of times. Pictured are templates for the scarf joints on the tie beams, templates for the rafter angles (8:12 and 3:12 -- the smallest one is 3:12), and the template for the dovetail joints. One other tool I use is a pencil. I've been using colored pencils that I've had in a zip lock bag for years and haven't used for anything else. The darker colors work best.

You can buy and use many different expensive tools for timber framing. You don't have to. You don't even have to use the tools I'm using. How many frames have been completed over the years without any power tools whatsoever? More than have been completed with the help of power tools, I bet. A chain mortiser or a Beam Boss or some other 'expensive' (this is a relative term, of course) tools would be nice, but I can't justify the expense of them for this project. One of the objects, afterall, is to pay for everything without going into debt.