The swivel base was in the "mid" position so that one could raise or lower the seat about the same distance. I decided to keep that setting but lower the seat somewhat by modifying the legs so that the bottom of the leg is flat.
I designed the top of the leg to have a cloud lift detail - a very Greene and Greene motif. The cloud lift has a sharp inside corner. I decided to define this inside corner with the table saw. I first band saw part of the front then cut the inside corner with the table saw:
That flat is not too appealing, but it will get rounded over with the template and flush trimming bit. Ok - so, I figure I'm pretty smart and I'll try to flush trim the tip without a backer by doing a very slight climb cut at the very tip. Ooops! Did not work!
Fortunately, I left quite a bit of extra wood on the other end. Oh yes, I had pre-drilled the holes for the wheels. Since I had to redraw the profile of the leg farther back I had to drill another hole for the wheel. This left the old hole in place which I plugged up with some maple. Hopefully no one will notice (except for everyone on the internet who happens to read this blog!)
On my second attempt I clamp an MDF backer board to the bottom, flush trim the tip, then remove the forward clamp to flush trim the remaining part of the top:
Notice the blue tape. I like to put tape on the template for the first pass to hog off most of the material which is likely to result in some burning, remove the tape and run a second pass where I am removing very little wood with no burning (hopefully).
The flush trim bit does a nice job but some wood is left on the inside corner which I remove with a shoulder plane and chisel making sure I go across the grain:
Next I cut the leg to final length and then cut the dovetail on the tablesaw. I figure that a 17 deg dovetail seems to do the trick:
I hand plane the sides of the legs and use a file and sand paper up to 180 grit on the top of the leg. Here is what they look like:
As you can see, the dovetails seem rather loose at the bottoms. However, the metal flares out at the bottom. The dovetails are actually pretty tight and I need to use a hammer to drive them home.
The next step is to install the quarter round pieces to hide the metal hub. Or at least I thought they would be quarter round pieces without thinking too much about the shape. As a test I glued 4 square blocks of cherry together with paper in between and turned them on the lathe. After separating the pieces I quickly discover that quarter round pieces will not work. I need circular arcs that are less than quarter round pieces. I take one of the blocks and use a hand plane and chisel to define the desired shape, which you can see below on the right:
Well, the lathe will not work. I guess its time for some hand work. So I grab the bubinga blocks and determine the desired arc:
These blocks are not long. The safest way to cut away most of the waste is with the band saw. I am making a 45 degree cut here:
Next I clamp the piece and use a rasp across the grain to hog off most of the waste, a hand plane with the grain to smooth the piece along its length, followed by a small file and sandpaper:
Now I glue the circular arcs onto the base. Note that I had hand planed the two reference sides before shaping so they are ready for glue up. The legs are about four inches wide. I glue the top 2.5 inches of the arc pieces since the grain is running in opposite directions. We need to allow for wood movement and I figure 2.5 inches is pretty common for tenon widths so it should be fine here.
The nice thing about those blocks is that they force the legs into 90 degree positions. After the glue dries I then screw on a bottom plate (not shown) with #14 screws that screw into the dovetails. I also screw into those dovetails from the top as well. Those screws from below and above secures everything very well.
Those legs are not moving!
When I am ready for finishing, I will round over the edges, wet the wood to raise the grain, then perform final sanding with 220 grit. However, I'll quit here. Time for a beer.
That flat is not too appealing, but it will get rounded over with the template and flush trimming bit. Ok - so, I figure I'm pretty smart and I'll try to flush trim the tip without a backer by doing a very slight climb cut at the very tip. Ooops! Did not work!
Fortunately, I left quite a bit of extra wood on the other end. Oh yes, I had pre-drilled the holes for the wheels. Since I had to redraw the profile of the leg farther back I had to drill another hole for the wheel. This left the old hole in place which I plugged up with some maple. Hopefully no one will notice (except for everyone on the internet who happens to read this blog!)
On my second attempt I clamp an MDF backer board to the bottom, flush trim the tip, then remove the forward clamp to flush trim the remaining part of the top:
Notice the blue tape. I like to put tape on the template for the first pass to hog off most of the material which is likely to result in some burning, remove the tape and run a second pass where I am removing very little wood with no burning (hopefully).
The flush trim bit does a nice job but some wood is left on the inside corner which I remove with a shoulder plane and chisel making sure I go across the grain:
Next I cut the leg to final length and then cut the dovetail on the tablesaw. I figure that a 17 deg dovetail seems to do the trick:
I hand plane the sides of the legs and use a file and sand paper up to 180 grit on the top of the leg. Here is what they look like:
As you can see, the dovetails seem rather loose at the bottoms. However, the metal flares out at the bottom. The dovetails are actually pretty tight and I need to use a hammer to drive them home.
The next step is to install the quarter round pieces to hide the metal hub. Or at least I thought they would be quarter round pieces without thinking too much about the shape. As a test I glued 4 square blocks of cherry together with paper in between and turned them on the lathe. After separating the pieces I quickly discover that quarter round pieces will not work. I need circular arcs that are less than quarter round pieces. I take one of the blocks and use a hand plane and chisel to define the desired shape, which you can see below on the right:
Well, the lathe will not work. I guess its time for some hand work. So I grab the bubinga blocks and determine the desired arc:
These blocks are not long. The safest way to cut away most of the waste is with the band saw. I am making a 45 degree cut here:
Next I clamp the piece and use a rasp across the grain to hog off most of the waste, a hand plane with the grain to smooth the piece along its length, followed by a small file and sandpaper:
Now I glue the circular arcs onto the base. Note that I had hand planed the two reference sides before shaping so they are ready for glue up. The legs are about four inches wide. I glue the top 2.5 inches of the arc pieces since the grain is running in opposite directions. We need to allow for wood movement and I figure 2.5 inches is pretty common for tenon widths so it should be fine here.
The nice thing about those blocks is that they force the legs into 90 degree positions. After the glue dries I then screw on a bottom plate (not shown) with #14 screws that screw into the dovetails. I also screw into those dovetails from the top as well. Those screws from below and above secures everything very well.
Those legs are not moving!
When I am ready for finishing, I will round over the edges, wet the wood to raise the grain, then perform final sanding with 220 grit. However, I'll quit here. Time for a beer.
Question, working on same type project. When cutting dovetails to fit hub, are they cut straight down leg or tapered to fit hub dovetail?
ReplyDeleteHi there! I cut the dovetails straight. The metal sides may have been tapered, but as I recall it seems that the one side was pretty straight and the other was more arc'd than tapered so as to push the dovetail against the straight side. But I may be wrong there. Next time I may try some tapered cuts but that would definitely complicate things and I suspect that each dovetail may have its own taper since those metal sides were definitely not to any exact tolerances. With the glue blocks and big screws the legs seem pretty solid. Thanks for looking! I've been out of woodworking for about two years but I am about to dive back in with another office chair.
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