Archive for the Category ◊ Techniques ◊

Author:
• Wednesday, September 30th, 2020
joinery

Disclaimer: Or what they do tell you but you might not notice.

Perfection is not the fundamental quality or even the goal of good joinery. Instructional promises of “perfect” joints, and especially “perfect every time,” are missing the point.

The skillful craftsperson is always is working within a sensitively understood range of tolerance. Understanding that range, and what lies beyond each end of it, are the keys to excellent work. You practice and refine your skills to develop that understanding and feel. You do not practice with an eye on perfection. The pursuit of “perfect every time” is naive and counterproductive because it misses the point. 

This is generally true in any field. The mason knows the idea is to make a good wall despite the imperfections inherent in every brick. The violinist continually makes tiny variances in the intonation of notes depending on the musical circumstances. I think if you ask a pitcher what is the perfect curve ball, he would say the one that ends up in the catcher’s mitt after the batter swings. 

And yet woodworking joinery seems to often be taught, and woodworking machinery promoted, as if the idea is to make, if you could, a 9000-micron tenon to fit into a 9000-micron mortise. And when you inevitably fail, you are supposed to keep practicing with that perfection as your target. 

I suggest instead that you practice to learn how much deviation to tolerate from flat, straight, square, on the line, etc. Learn how fit can vary and still function and look great. This is not to license sloppy work! Your work can and should be excellent. But learn when and how variance matters. Learn tricks to make small deviations cancel through the building process. Understand the concept of one-sided tolerance. (Please see this post.)

Appreciate too, that wood is compressible and this varies with the species so you must adjust your tolerances. Consider that the ideal (I don’t mean perfect) tenon fit where you gently and evenly swoosh, not force, the tenon into the mortise, and then it stays when you hold the assembly upside down. That involves slight wood compression, and you have to work with that. 

There’s another thing “they don’t tell you.” It is fine to practice making an individual joint such as a mortise and tenon but you have not mastered the joint until you can make it in context such as eight of them working together in a table. The same is true for case joints like dovetails. So, by all means, practice, but practice intelligently, and don’t forget that you have to also practice by making things.

Do not get distracted by perfection. Aim for excellence

Category: Techniques  | Tags:  | 5 Comments
Author:
• Monday, September 28th, 2020
understanding wood

Disclaimer: Or what they do tell you but you might not notice.

Unless you get really good at understanding wood, you cannot be a really good woodworker.

A chef without a deep appreciation for the ingredients will always be at a loss for making outstanding food. You’re a woodworker. You make useful, beautiful things. Wood is your medium. It offers the infinite variability of the biological world, which gives it profound potential in your hands. 

Read the books. Start with Understanding Wood, by the late Bruce Hoadley, and Wood, by Eric Meier. Use the Wood Handbook produced by the U.S. Forest Products Laboratory for reference. Here are some resources.

Observe wood “in the wild” in furniture everywhere. Develop a discriminating eye and taste. See how wood ages. To develop a healthy obsession would not be overdoing it. 

Most of all, get lots of different wood in your shop and mess around with it. See how different species and different boards react to planing, joinery, being four-squared, finishing, and so forth. Understand grain and figure, and how to make the best structural and aesthetic use of them. Be aware of the options in manufactured boards – that’s wood too. 

But Rob”, you say, “Chill out, I just want to make nice bookcases and house stuff in plain old pine that I pick up at the home center. I don’t need curly maple.” OK, great, good work, but which boards do you select? All flatsawn, or should you search through the stack for some rift or quartered stock? What is the moisture content of the wood in the store, and what will happen later? Why is the pine you bought this time acting differently from the stuff you bought last time at the same store?

Bottom line: you must know wood and know it really well. 

The next time you look at a project article in one of the magazines, the wood will probably get passing mention at most. Most woodworking publications, unless specifically on the topic of wood, discuss little about it. But if you want to build something and make it good, think carefully about the wood. Use your knowledge, search widely if necessary, buy carefully, and think it through

A corollary of this imperative is that what works structurally and aesthetically in one wood may not work in another. The wood selection should be integrated into the design and construction plan. The hands-on techniques employed will differ depending on the wood. Except for the design itself, wood selection is the most important stage of a project. 

One more thing: wood can and will disappoint you – sometimes, but more than you might expect. Maybe it turns out to have weird defects, it dresses too thin, or it just doesn’t look like you thought it would next to that other wood, and on and on. 

Don’t just buy more, learn more.

So, yea, get your tools, your shop, your designs, your joinery skills, and even your super-sharp edges, but it cannot be overemphasized: don’t forget to get really good with the wood, and always continue discovering more about it.

Author:
• Sunday, September 27th, 2020
woodworking insights

Disclaimer: Or what they do tell you but you might not notice.

Learning in any field takes place on at least two levels. First, there are the overt knowledge and skills that necessarily dominate the instructional material and the student’s efforts. Yet, there are always the unwritten, perhaps even unsaid, insights without which we never feel truly in command of the field. This is “Oh, now I get the idea . . .” — on the road to mastery. 

With all due respect for the many wonderful woodworking teachers out there, it is difficult to transmit these key points in the environment of most formal instruction, especially written. In fact, these essentials may more often be “discovered” by the student in the quiet reflections of “putting it all together.”

These are the sorts of things that despite all your training, you realize six months into the job. Or that the instructor casually mentions in conversation after class when he sees what an eager student you are. Or that dawn on you during a long nighttime drive back home. These are synthesis ideas.

There is a simple continuing theme of this weblog: I greatly enjoy woodworking and find it meaningful. I want to help you do the same, particularly by discussing matters from a viewpoint that is typically neglected in most woodworking publications. With that in mind, I offer this series of posts to present what I think are pivotal nuggets in the various aspects of woodworking. I hope they help you leap ahead to better woodworking or at least reinforce your woodworking mindset. 

Hey, I’m not so foolish as to think I know it all, so please do comment to share your insights on each of the topics as we go through them. The first topic will be, of course, wood. 

Author:
• Saturday, June 27th, 2020
long-grain shooting board

My new jig for long-grain shooting accommodates workpieces up to 36″, a big increase from the old jig’s capacity of 24″. I was motivated by a few occasions when I had to use the somewhat awkward setup of clamping a long workpiece to a support board and running the plane on the benchtop. 

I have found that shooting a three-foot long piece is really not a problem with a good setup. And the big jig imposes no disadvantages for shooting much shorter pieces. 

My 10/31/19 post is a discussion of long-grain shooting. 

Construction is simple from 3/4″ MDF: The workpiece platform is 6″ wide on top of the base, which is 9″ wide, to make a 3″-wide plane runway that is covered with thick PSA UHMW plastic. I like the Lie-Nielsen #9 but any bench plane would work.

The workpiece is controlled from the front by the end stop, and from the side with clamped scraps. I find no need for an elaborate, screw-mounted permanent lateral clamp board because while it would offer some convenience, it would also limit the functional range of the jig. Top (downward) control is supplied by your hand. 

long-grain shooting board

When shooting a narrow workpiece, such as a door stile, which might temporarily have a convex or concave non-working edge, there is the danger of the workpiece flexing against the straight edge of the lateral control board. The solution, shown above, is to use two separate lateral control boards, each butted against a section of the (non-straight or suspect) non-working edge of the workpiece. 

The cleat at the right end of the jig is an afterthought (you know what I mean: “Doh!”) that allows the jig to be clamped with dogs with a conveniently minimal opening of the tail vise, which is then tightened. 

It works beautifully.

Category: Jigs and Fixtures, Techniques  | Tags:  | 6 Comments
Author:
• Sunday, May 31st, 2020
setting hand plane cutting depth
Click on the photo to see a larger version.

It is not surprising that setting the depth of cut in a hand plane can be difficult to learn. After all, we are dealing with differences of as little as a thou or two with a smoothing plane, and even a heavy cut with a jack plane should have a balanced, efficient setting. 

Ultimately, the best gauge of the proper blade projection is the performance of the plane. You sense the bite of the blade, observe the shavings, and make adjustments.

Nonetheless, you want a good initial setting before the plane is brought to the workpiece to avoid lots of trial and error adjustments after starting to plane. Both the left-right balance and the overall depth of cut must be set. These initial adjustments can be made in two ways: visual and tactile.

To see the blade projection, sight down from the front of the sole at a very low angle with a lamp positioned in front of your forehead. The light will be diffusely reflected from the sole (metal or wood) but not from the protruding blade, which thus appears black. Subtly shift your viewing angle to see the thin black strip of the blade. (As a further optional visual aid, note that light will probably also be reflected from a neatly filed tiny wall at the back of the throat at the extreme sides of the mouth where the curve of the blade camber reveals it.)

The photo at top shows a moderately cambered jack plane blade projection. Click on it to see a larger version.

Adjust the blade for lateral balance with the lever, Norris style adjuster, or hammer, depending on the type of plane. Usually, this is easier to observe and manage with a substantial overall blade projection, which you can then back off to a shallow cutting depth. For a smoothing plane, I make this depth almost nothing and then increase it as needed when I start planing. For jack plane work, I usually go directly to a more aggressive cutting depth. 

For tactile confirmation of the visual adjustment or instead of it, use a small block of wood about 5/32″ thick as shown here. I learned this method from David Charlesworth. I prefer to use the edge, not the corner, of the block to pull shavings from each side and then from the center of the blade. 

testing plane blade depth

As with the visual method, get the lateral balance correct first, then go for a good overall depth of cut. The difference with the tactile method, however, is that it is easier to start with a minimal depth of cut to make the lateral adjustment. The assessment is made by feeling the pull of the cutting edge as it takes a shaving from the little block of wood.

Below is an example of the result. Note that this is to illustrate the principle. In practice, I do not usually bother to turn the plane over to look at the tiny shavings. The assessment is done by feel. You can see that this blade has a nice small camber but the lateral adjustment is not correct. The cutting edge pulled almost nothing on the left side in the photo. 

testing plane blade projection

For smoothing plane work, I’m more likely to use the tactile method because it directly gauges precise small adjustments that may be hard to see. For jack plane work with a moderately cambered blade, I’m more likely to use the visual method because the more prominent blade silhouette makes an adequate adjustment fast and easy.

For planes with a straight-edged blade, such as a rabbet block plane, the same methods apply but you are trying to get an even blade projection across the full width of the mouth.

Category: Techniques  | 6 Comments
Author:
• Tuesday, March 31st, 2020
dovetail transfer tools

A critical step in hand-cut dovetailing is accurately marking out the second piece – usually the pin board – from the completed first piece – usually the tailboard. 

Sure, to make a good dovetail joint, you have to be able to reliably saw to a line and chisel to a line. You also have to understand the mechanics of the joint to appreciate how to tweak the contact surfaces and where you have a bit of tolerance and where you don’t. But if the transfer step is inaccurate, it’s all a losing battle.

So, let’s look at several options

Keep in mind that all of this depends on several variables including pin width, the texture of the wood, and your personal eyesight, lighting, type of saw, and technique. An effective marking out in cherry using a ripcut dozuki may be difficult in red oak using a Western backsaw. 

chisel point drafting pencil

A plain old pencil seems too crude for the precision required in dovetailing and yet it can work well for some. All of the pencil mark is in the keeper wood, so you have to saw to one side of it without touching it at all. A very clean, consistent line gives the best chance for success. A 2mm drafting lead sharpened on 320-grit sandpaper to a chisel point (above) can produce an almost knife-quality line, especially with 2H lead on a diffuse-porous wood like cherry. That said, a pencil is not my preference. 

Starrett scriber

I’ve used a scriber more than anything else for this job, perhaps because that is what I used long ago while learning (first learning, that is). I prefer the type of point on the Starrett scriber (above), which ends in a small, straight conical taper. Unlike a gradual curved taper, I can clearly tell when the scriber is or is not up against the wall of the tail wood. 

Used properly, the scriber point hugs the wall of the tail wood as it bites into the endgrain of the pin board, without any chance of it cutting into the side grain of the tail as a knife might. Thus, the bottom of the tiny V groove created by the scribe point is exactly under the tail wood wall. 

This works best if the sawn (and possibly pared) surface of the tail is straight and clean. Otherwise, the scribed line will be not straight and therefore probably confusing to follow with the saw.  

I have found the scriber effective in ring porous woods like red oak as well as fine, diffuse-porous woods like pear. The downside is the scribed line is not quite as clean and fine as a knife line. 

Next: a look at different marking knives and more.

By the way, go here for my free 42-page Dovetail Instruction Guide that I wrote several years ago for Craftsy. It really gets down to the sawdust and shavings to lead you to success. 

Category: Techniques  | Tags:  | 2 Comments
Author:
• Sunday, February 23rd, 2020
levelling table legs

In theory, the bottom tips of all four legs of a table should be in the same plane so it can sit on a flat floor without wobbling. Remember, however, the words of Yogi Berra, “In theory, there is no difference between theory and practice. In practice, there is.”

Now, if you made uniform leg lengths and mortise-and-tenon positions, you should have a flat base after assembly that requires no adjustment but stealth gremlins almost always prevent such perfection. 

On the other hand, consider that rarely is a floor flat over the area on which the table stands, so making the four legs true is really just playing the odds. Furthermore, a table, especially a large one, may flex when you place it on the floor to produce an automatic correction. The same goes for chairs. Therefore, all of this is often of no concern at all – in practice. 

For a small table though, this issue may be a significant concern. The small area of floor on which it stands may indeed be flat, the table may not flex much, and it feels creepy when it wobbles a lot. So, let’s look at how to assess this. 

It is best to do this with the top attached in its final configuration, which contains any flex in the frame induced by the top piece.

The simplest method is to put the small table on a true flat surface such as the table saw. If such as surface is not available, you can turn the table upside down and use winding sticks on the tips of the legs. Note that this may introduce error if the frame of a larger table flexes a bit differently than when it is right side up. In any case, for a larger table, I do not go hunting for a very flat floor, which probably does not exist; I just do not worry about the whole matter.

For small tables, I do like to get it pretty close. You can take off the error from the one long leg, as determined by how the table pivots on the flat reference surface, but I prefer to take off half that amount from each of the two long legs.

OK, if you have done everything just right in the shop and now place the table on the floor where it will live, which is not likely to be flat, and it wobbles enough to be annoying, what do you do? Shim it. A layer or two or more of tape such as duct tape is just fine – in theory and in practice.

Category: Techniques  | 4 Comments
Author:
• Tuesday, December 17th, 2019
cross-rail joint

For rails that cross over their widths, this joint is very doable, strong, and neat. It has several advantages over other options for this situation. (Note this is distinct from rails crossing over their thicknesses, face to face, where the familiar half-lap is a good choice.)

Let’s take a look.

Each crossing member has strength distributed over nearly its full width, and there is no unsupported portion of the width. Furthermore, there is mechanical resistance to twisting in all directions. This is superior to a cross-halving (or “cross-lap”) joint, which is just a vertically oriented half-lap.

This is a strong joint with substantial long grain-to-long grain glue surface – more than 8 square inches. Note that the five dowels are long and continuous from one side to the other side of the joint. Cross-halving joints yield minimal long grain apposition.

It is much easier to conceptualize and execute this joint the than refined but elaborate cross-halving designs that involve stepped notches, sliding double-dovetails, or tapered notches. They make my head hurt. 

For an enduring neat appearance as well as strength, the pieces entering the dado have outside shoulders. This differs from some versions of the cross-halving joint that are designed to correct the problem of unsupported width, and involve a dado that houses the full width of the entering piece, which can leave gaps when the housed member shrinks in thickness.

cross-rail joint finished

Woodworkers of all stripes will be pleased to know that this joint can be executed by hand, by machine, or a combination of both. In fact, you will see that a single shop-made jig can be easily adapted for use with various workpiece thicknesses and even various widths. 

Full disclosure: a disadvantage is that it must be clamped from the ends. This could be awkward for very long pieces, though that is not a likely application. 

Next: How to make it. As with all woodworking, it’s a matter of being accurate when it counts.

Category: Techniques  | Tags:  | 4 Comments
Author:
• Sunday, December 15th, 2019
dovetail markers

Here are the dovetail angles that I use. There is more than one good way to do almost everything in woodworking, and there are many situational exceptions, so these are not absolute. I do, however, know that they work. For the most part, they conform to what is usually written and taught, but here I also offer explanations for the various options.

My go-to angle for through dovetails in most hardwoods is 7:1 (8.1°), such as for a carcase or box in cherry, maple, or walnut with stock thickness of 9/16″-13/16″. It has enough angle to form a strong mechanical lock but not too much to produce fragile tail corners or overly fussy fitting. Vulnerable tail corners can be annoying in the making stage even though they are shielded after assembly. 

carcase dovetails

For more brittle, harder woods such as the curly oak shown below, I prefer 8:1 (7.1°). This helps to prevent chipping at the corners of the tails but still provides enough mechanical lock because the wood is less compressible. For the ovangkol small chest shown in the second photo below, I used 7:1 but the wood proved to be harder and more brittle than I first thought, so maybe I should have used 8:1.

red oak dovetails
ovangkol dovetails

For softer, more compressible woods such as pine or aspen, 6:1 (9.5°) works well. The steeper angle produces more mechanical lock, and chipping is not a concern.

Half-blind dovetails are a different matter. The shorter length of the tails usually requires a little more slope to create a good mechanical lock. 5:1 (11.3°) works well in most cases. It also just looks right to my eye. This study drawer with poplar sides and pear front that I keep in my shop is a good example. Using a harder wood for the sides and/or a thicker front (longer tails), I would consider 6:1, ultimately going with what looks right.

half-blind dovetails

Through dovetails in thin stock deserve similar consideration. Very generally, for thin pin stock (shorter tails) consider using a bit more slope than for similar circumstances in thick stock.

Interestingly, in all of this, the mechanics and the aesthetics seem to dictate the same answer, and not, I think, by coincidence. 

I have been using the shop-made bubinga markers shown in the photo at the top for many years. Unlike most commercially produced markers, they allow you to mark the entire length of the line on the face grain and end grain with one positioning. I detailed their construction in an article in Popular Woodworking, November 2009, issue #179.

Category: Techniques  | 5 Comments
Author:
• Sunday, December 01st, 2019
shooting tips

Another question from a reader: “My trouble in shooting is (I guess) in advancing the wood.  I often find myself in a situation where I’m feel like I’m pushing the wood very firmly against the toe of the plane and still not getting any bite from the blade.  This problem seems to come and go and I have yet to diagnose what I’m doing wrong.”

There are at least two possible reasons for this.

1. The blade may not be sharp enough, causing it to skid on the wood rather than cut it. The whole system (workpiece, plane travel, blade edge) may be deflecting, preventing the blade edge from engaging the wood. 

Of course, end grain is harder to cut than long grain. Paring end grain is how many woodworkers test an edge. However, there is another reason why sharpness is so critical that is peculiar to shooting. 

Planing in the usual manner with a bench plane, we intuitively sense that we can extend the working life of a gradually dulling edge by pressing down harder with the plane. Related to this, we find that it is necessary to advance the blade further (depth of cut adjustment) to get it to take the same shavings as when it was sharper, though with more effort. Eventually, we head back to the sharpening bench.  

Brent Beach offers a technical discussion relevant to this. The basic idea is that the extremely narrow lower wear bevel in a sharp blade has less area against the wood, and so is able to generate more pressure (force per unit area) on the wood than does a dull blade with a wider lower wear bevel. The sharp blade compresses the wood and bites into it.       

In shooting, the plane does not ride on the wood, it rides on the edge of the track, and so you cannot regulate the edge pressure against the wood as you can with ordinary planing. The blade has to be sharp enough to cut without your “help,” so to speak. Actually, I have found myself intuitively trying to shove the workpiece toward the plane as the blade dulls, but that is awkward at best, and tends to produce inaccuracies.  

Furthermore, end grain is less compressible than side grain. 

2. Another possibility is that the fence is set slightly greater than 90°. This will cause the workpiece to register against the sole of the plane near the fence but not reach the sole where the cut begins. It only takes, say, a couple thou of error for this to happen. Furthermore, as an insufficiently sharp blade moves along to eventually meet the workpiece, it might push it away rather than cutting into it. (This is another example of the general principle that a tool, hand or power, given the opportunity, will move the workpiece instead of cutting it, and/or move the tool itself.)

The shooting board fence may start out dead-on at 90°, but if it is not very firmly set, it is easy for it to eventually get pushed to greater than 90° because that is the direction of your force on it in use. 

In summary:

1. Sharp – wicked sharp – is a must for shooting!

2. The shooting setup has to be not only statically accurate, but also dynamically stable in use.

Category: Jigs and Fixtures, Techniques  | Tags:  | 4 Comments