Fettling: Making the Shop More Functional

I think beginning woodworkers (and I still consider myself a beginning woodworker) are challenged by all the setup required for the shop to work well. Many tools are sold looking like they are functional, but with serious flaws. And even those that don't have serious flaws need fettling to perform at their potential. These tasks often seem endless.

The router table pictured above came from an estate, complete with router, for about $25. I knew I needed a router table, and I also knew it would be a while before I make the one I have planned. This seemed like a good solution (still does), but the the stock fence, which was designed to look like would allow straight guided cuts as well as small scale jointing, had challenges.

Ryobi is the manufacturer, and the table and fence are made from aluminum. They look like they were cast and machined to be flat, but the fence itself curves significantly. When I placed a straightedge against it, there was a visible deflection of up to 1/8" at the center. Whether I used it with the plastic guide surfaces or without, the fence caused anything that ran over it to stall when it hit the gap, and the act of correcting this problem would put a wrinkle in the line of the routed groove.

I had to fix the router fence before I could route the slots on the cold frame lights. And to do that I needed to finish setting up the jointer (finally). I spent a night last week setting up the jointer, and about an hour and a half this weekend flattening a fence and setting it up to receive the bolts. Two more fettling tasks done. And the router table performed to the tolerances I required (something it would not have done before adding the new face to the fence).

It turns out that the new surface is not actually flat, and some day I may sink the bolts further in and run it over the jointer while it is attached to the fence. Today is not that day.

Learning to Cut to a Line

My friend Brian says that great woodworking requires cutting to a line accurately. I don't think it matters whether the accuracy is by hand or by machine, but I know that he was talking about hand work.

He suggested an exercise for learning accuracy with a handsaw, one I found similar to playing scales and arpeggios on the piano: deceptively simple, repetitive, but challenging to perfect. I've started doing this exercise whenever I have a few spare moments in the shop:

1. Mark a shoulder line 1" from one end of a wood scrap
   This length amplifies error enough that you can see even a small divergence from the line).
2. Using a square, mark lines from the shoulder line to the end of the board
   Make as many as you can fit across the scrap—Brian suggests putting them 1/8" apart, but I've been marking them further apart than that).
3. Wrap the lines onto the end
   This exercise leaves me wishing for a saddle square: I've found that error creeps into the intersection with almost every set of lines—it isn't obvious until I cut to the line, but then I can see that the two lines tend to be as much as 1/32" off.
4. Cut to the shoulder following the lines
   Check the resulting kerfs for square both across the top of the board and running down to the shoulder line. Initially I was cutting on the line and realized that this prevented me from judging how accurately I was cutting to the line. Then I tried cutting next to the line, which gave me enough visual feedback, but would require chisel work to complete a joint. So finally I conclude that I should strive to cut the line in half. This leaves enough pencil to judge accuracy, and when I'm accurate removes all of the waste.
5. Cut off the kerfed part of your and start again with #1
   Rinse and repeat. Brian's teacher was required to do this 200 times before being allowed to cut dovetails. I've only done it twice, and it seems like it might just take 200 times before I am accurate with this.

This exercise develops at least three skills required for cutting good dovetails:

1. Cutting square to the board end
   Tails need square cuts. And if you cut tails first, this allows you to cut matching tails at once.
   
2. Cutting to the shoulder line on both sides
   Cuts past the shoulder will show.
3. Following a line
   By following the layout lines exactly, you end up with tight joints that didn't require a lot of adjustment with a chisel.

I hope to find that this exercise has improved my dovetails next time I use them. First I'm learning the hard way how to flatten a board with a hand plane: lesson 764 in woodworking - S4S does not mean flat.

Thoughts on Mitered Corners

I've been thinking about ways to join wood at 90 degree angles. This is in part because I'm starting to think about making storm windows for the basement, and in part because there are picture frames in my near future. So I spent part of this week contemplating joints that have a miter on the show face.

Of course, the simplest way to do this is with a straight miter:

The matched angles of a miter provide some resistance to separation, but the primary benefit lies in the concealment of all the end grain. This is aesthetically pleasing, and can be advantageous in joints that need to endure weather, but nothing can change the fact that end grain to end grain provides a weak glue joint. So even with modern glues I always nail through with wire brads when making a frame.

Another way to strengthen the joint is to add some long grain to long grain contact. We can do this with a mitered half lap:

This has the added advantage of having more edge contact between the boards. You can also put a blind peg in from the back to keep these mated pieces snug. This does reveal some end grain on one side, but provides a much stronger joint. Although this joint looks simple enough, it can be hard to wrap your mind around the geometry: notice that one piece requires two cuts, but the other requires three. When I was drawing this, I kept trying to "cut" the wrong part of the the mating board, so before making any cuts I double check my layout.

You can take the long grain to long grain theme to another level with a mitered bridle joint. This joint starts to get complex.

Even with the increased complexity in the joint, this one is somewhat easier to understand in layout: each piece has one angled joint and one square joint, where the half lap has a more asymmetric structure, with one angled joint on on piece and both an angle and a square on the other.

While I was thinking on variants, I came up with the idea of adding a mechanical joint to the glue joint. I've never seen this done, but it must have been, and it seems that adding a single dovetail on each joint could be elegant and effective:

Properly done, this would be a great way to brag.

Another way to use a mechanical joint is to key the joint: I didn't have time to draw this one, but I hope to add it in the next few days...

Tails First or Pins First?

I've cut dovetails using both the tails-first and pins-first methods. When I was taught to do this, it was using the pins-first method, and although I was a beginner, the joints were very tight and accurate. They just required a lot of correction along the way.

Soon afterward, I saw a video by Rob Cosman on making dovetails and he cut the joint tails first. It looked to have many advantages for speeding the process and making it more accurate so I started experimenting. I soon found that a pencil was inadequate for marking the pins, where it worked just fine for marking the tails on a pins-first joint. This caused me a lot of grief as I didn't have a marking knife. I tried a number of solutions, including a sheetrock knife (don't try this at home, kids), but they all compromised the tightness of the joints. Finally, Fine Woodworking did a test on marking knives and included a $3.37 solution: the Xacto Knife. Problem solved, and my tails-first joints got much tighter.

Yesterday, Christopher Schwartz posted a list of reasons why he has adopted the tails-first method, and a couple of them are destined for my shop: gang cuts should be a real time saver, and I'll be trying the rabbetting trick soon after the moving fillester arrives in my shop.

Box Assembly

Yesterday night I returned to the shop. The bottom and insides of the cherry dovetailed box had been finished with two coats of Tung oil finish and a coat of wax. The finished cherry glowed almost golden, practically begging me to glue it together.

Having come this far without incident, I wanted to be sure to get the glue up right. I checked my labels, still visible on the outside of the box, and laid out the parts in relative position with the bottom in the center. I placed the sides with the bottom slots of each piece laid alongside the bottom. I had clamps ready if I should need them; also a 12" rule, a mallet, four pine blocks cut with fingers slightly thinner than the tails, glue spreaders and glue cup cut from a small paper cup, a spray bottle of water, paper towels, and scraps of cherry created when I cut the dovetails.

Surveying the scene, I ran through the process in my head. It seemed that everything I needed lay in front of me. I used some poster putty to temporarily attach the paper glue cup to the bench top (have you ever chased a glue cup under the bench while your open time was ticking away? I have.). Then I poured enough wood glue into the cup and started spreading glue on the long grain of the pin boards. Perhaps I should have also spread glue on the tail boards, but I chose not to do so. I knew the tails had a fairly tight fit, and I wanted to minimize squeeze out.
After adding glue to all the pins, I lightly inserted one set of tails into the corresponding sets of pins, first on one side and then the other. Using one of the pine blocks to protect the cherry side from the mallet, I tapped the end home, working alternately from one edge to the other. When that end was set, I turned the box over and slid the bottom into its slot, then repeated the process of inserting the tails and driving the second end home.

I now had a box. Using the 12' rule, I tested for square. Then I looked at the inside for squeeze out. At this point I realized two sections were not driven all the way home, so I applied the mallet just a little bit harder to drive them into place. The box was still square, and there was only one spot of squeeze out. Since the inside was already finished, cleaning this was no big deal. I sprayed a paper towel lightly with water and wiped away the glue spot.

At the last, I looked at the dovetails critically. Only one spot looked like it needed significant help, so I made a small wedge from one of the cherry scraps. I dipped this in glue and lightly tapped it into the gap (making sure to line up the grain so it would appear to be part of the pin – I think end grain hides better than edge grain and its easier to make the wedge that way). So now the assembly is done. My only worry is that I may have driven this wedge a little too far and deformed the tail enough to be noticeable. We'll see tonight when I trim it flush.

Thoughts on Dovetails

Since I've been making dovetails, I've thought a lot about why they are made the way they are. The first time I tried a dovetail, I automatically laid out the joint with half tails at the top and bottom. I soon learned that this was not recommended.

Tage Frid, in the first book of his excellent series Tage Frid Teaches Wooodworking stressed that dovetails should start and end with half pins and not half tails. I believe that the reason for pinning top and bottom is to provide a mechanical restriction should either board try to cup away from the joint.

Using half pins at top and bottom theoretically fixes the pinboard and tail board from cupping. The half tail offers no such restriction. Because the angle of the tail runs with the grain rather than across it. there is nothing preventing the edges of either the pinboard or tailboard from cupping away from the joint. The first such restriction will be the first pin. So the rule of starting and ending with half pins is a good one because it improves the chances of the joint staying tight.

Today I discovered that this good-sense rule was not always practiced in the past.
If you look at the section on Antique Dovetails in this Popular Woodworking blog entry, you'll see that only one of these follows Tage Frid's admonition. Instead, most started with a half pin at the top, and ended with a half tail at the bottom. As evidenced by the half pins at the top, these craftsman obviously knew that half pins offered an advantage. But why didn't they pin the bottom? At first I guessed that they wanted the top to stay absolutely flush with the drawer because the user was most likely to notice gaps there. But if they were willing to pin the top, was it so much more work to create a half pin at the bottom?


On further thought, I suspect there was some planned advantage to this layout: there must be a reason why leaving out the bottom half pin was faster and easier. I suspect that reason is the groove holding in the bottom of the drawer. I obviously can't see the interior of any of the drawers Glenn Huey showed us, but I suspect that both the sides and front have a channel for the bottom that runs right through area of the half tail. Laying out with a half tail at the bottom allows the maker to work without fear of accidentally exposing these channels with a misplaced saw cut or chisel (something that can easily happen with a half pin). This advantage probably justifies a gamble on the stability of bottom end of drawer.

Carving Knuckles and Volutes: Peter Galbert

Peter Galbert just finished posting a series of blog entries on carving the knuckles and volutes on Windsor chairs. He describes the process carefully and accompanies it with clarifying pictures like the one above. If you've ever wondered about the layout and carving of these elements, take a look at these:

• Knuckles (part 1)
• Knuckles (part 2)
• Knuckles (part 3)
• Drawing Volutes
• Knuckles (part 4)

Photo copyright and courtesy of Peter Galbert

Dovetail Error #2

No, this is not a mock up for next year's jack-o-lantern teeth, but a real life example of cutting the tail instead of the waste. This demonstrates why you should always mark the waste, on both visible edges, before starting to cut and chop.

It almost makes me feel better that this error is over a year old. And it was a mock-up using scrap wood. And I was hurrying.

My New Year's resolution? Work smarter, not faster. The speed will come, and going slowly once is still faster than going quickly twice.

Warning About Magnetic Switches

I've always unplugged machinery before working on the motor or changing the blade. It seemed a bit overzealous, but machinery can remove fingers and more. You know: "It slices, it dices, it julienne fries." This is not what you want done to parts of your body.

Today a friend sent me a link that suggests there is more to unplugging your machines before working on them than just paranoia. I could not corroborate this information elsewhere on the Web, but the article describes how machines with magnetic switches can be tripped just by being bumped or otherwise shaken adequately. It makes sense. You can bet I'll be extra careful to unplug before changing blades. And I'll be looking for other sources that describe this phenomenon.

Dovetail Error #1

Notice the chisel (my thinnest) and how it compares the the waste area next to it. If your thinnest chisel is a 1/4", you cannot cut pins that run to the width of the saw kerf: your chisel will be too wide to remove the waste.

Three Lists of Essential Tools

Over at Lumberjocks yesterday, Tim Dorcas put up a blog entry about what tools a beginning woodworker might want to buy if the spending limit was $1000. It is primarily a power tool list, but a great exercise in prioritizing shop tools. I posted a comment about what a more minimalist shop might look like, but in principle I agree that Tim listed a set of tools that allows a wide range of work and will get you started.

I always enjoy this kind of list because it gets me thinking. Another great example is a list that Christopher Schwartz posted a while back. This won't fit a $1000 limit, but it gives a sense of what might be important in a more blended shop.

Finally, while trying to dig up Chris's post, I found another from Robert Lang that you can ponder. Enjoy!

Photo of violin maker's tools courtesy of Wikimedia Commons and Just Plain Bill

17 Board Feet of Maple: Furniture Build-Off

What can you do with 17 board-feet of maple? The idea intrigues me. Could you build a bench like the one shown here? A glass topped coffee table? A side table? A bookshelf? A wall cabinet?

For those who don't know, the board foot is a rough wood measure of 12 inches x 12 inches x 1 inch of wood. You don't need to keep those dimensions, though. You can halve one dimension and double another, for example. So one board foot could be 12" x 12" x 1", or 24" x 6" x 1", or 12" x 6" x 2", or many other combinations with the same volume.

With that in mind, 17 board feet could be a 17-foot long, 12-inch wide, 1-inch thick plank, or a 16.5-foot long, 6-inch wide, 4-inch thick post. It sounds like quite a bit of wood, but you won't be building an armoire with it, or a chest of drawers, or a dining room table. This puzzle has infinite solutions, but limited size.

Why am I asking this today? Because I stumbled upon the Fine Woodworking Furniture Build-Off and it captured my imagination. This is a challenge I would love to meet. I'm adding it to the Someday Maybe section of my project list, and even if I don't participate I'll remember the principle: a limitation can be inspiration.

Photo courtesy of the Wikimedia commons and Aaron Morse