Whenever possible, I would much rather use parallel clamps than long F clamps for gluing up work. With parallel clamps, pressure can be applied more accurately and, if needed, readjusted more reliably. That also means faster, which is important when the “pressure is on” during glue up.

However, little of my work is fully rectilinear with nice flat contact points and with all the surfaces at 90° angles. Therefore, a key additional ingredient is usually required to use parallel clamps: glue blocks. I consider glue blocks to be a standard work component of most projects. Because almost all of my work is one-of-a-kind, the glue blocks usually get discarded when the project is done, but that’s OK, they are still well worth the effort.

This approach is easier than trying to guess where the swivel-head sliding jaw and fixed jaw should contact opposing curved surfaces to properly direct pressure across the joints. Even after a dry assembly trial, there are likely to be too many uncertain adjustments to deal with during glue up crunch time when the meter is running. For similar reasons, F clamps are far inferior to parallel clamps for edge joint glue up.

The bottom line is that for table legs, curved case components, and so forth, I’ll do whatever I have to do to make the glue up a more predictable operation. Most clamp blocks are easily made from the bandsaw cutoffs produced during building the piece.

When a moderately long F clamp is useful, it is usually in support of parallel clamps or when the vault of the jaws is helpful to clear an element of the piece. For those occasions, the economical and widely available Jorgensen #3700 series work well enough. They also make the heavier duty but much more expensive 4500 series.

For long F clamps, I like the clutch system on the Jorgensens. When the head is set in place, it is sure to stay there throughout all the maneuvers during glue up that precede final placement of the clamp on the work.

I replaced the orange Jorgensen pads with red Bessey pads that fit perfectly on the swivel end of the sliding jaw. Bessey pads do not snugly fit the fixed jaw so there I attach thin cork sheet.

More to come on clamps.

For the other clamps in my shop, I’ve taken down one of each from the racks and have offered comments on their utility. These choices are largely matters of personal preference and very dependent upon the work being done, but hopefully readers will find some useful information and ideas.

These little 2″ and 2 1/2″-deep Bessey F clamps, 4″ and 6″ length capacity, respectively, are used almost exclusively for stop blocks, fences, jig setups, and the like. Sometimes the clutch type is easier to place precisely. Almost any decently made brand will do for these tasks.

The Bessey Varioclippix 4″ spring clamp has a sliding arm that greatly expands its capacity, flat pads that make clear contact with the work, and hand-friendly grippy inserts. These features make them preferable to the original Pony steel spring clamps. I store them gripped to pieces of brass sheet screwed to the bottom of a clamp rack.

The 2″ C clamp is sometimes just the ticket for tight quarters in jig setups. The Japanese mini bar clamp is useful for very small work where a parallel clamp is needed.

The Bessey 4″ deep x 8″ long F clamp (TG4.008 “Tradesman” 1″ x 5/16″ bar), below left, is a sturdy, reliable workhorse for a thousand tasks. The replaceable pads have never marred a work piece in my shop but they are not squishy and they stay in place. The key rigidity features are the I-beam bar and the corrugations in the malleable cast jaws. They are available in many sizes with different force ratings and handle features.

The very heavy and strong Gross-Stabil 12″ parallel clamp gives a broad, ultra-reliable hold down force. The lightweight Bessey UniKlamp is useful when the precision of a parallel clamp is needed on a small scale. The rectangular heads work well as stop blocks themselves. The balky engagement of the head is typical of Bessey parallel clamps.

I don’t know when I’ll next need this 7″ deep, heavy F clamp but I’ll be glad I have it then.

It is hard to overstate the versatility of the venerable wooden handscrew. Much of the magic of this tool derives from the ability of the rectangular wooden jaws to clamp as well as to be clamped. This allows creative arrangements that can solve lots of work holding problems. Final tightening is done with the outer handle, so the cloth friction tape is a big help there.

Excellent quality handscrews sold under many different brand names are made by the Dubuque Clamp Works in Iowa. Maybe I am the only person who finds the non-drying oil “finish” on their clamps annoying. It can transfer to some woods when the clamp is tightened hard, and in any case, seems unnecessary. I like the Besseys, which don’t have this issue and seem to work as smoothly as the ones from Iowa, though the latter are available in a larger range of sizes.

More clamps coming up.

What task produces some of the tensest moments in woodworking? Gluing up, right? And what are the main tools we use for that task? Clamps. Yet there usually is not much discussion about them, many woodworkers skimp on them thinking they’re not real tools, and they generally just don’t get much respect.

Let’s start with long clamps – bar clamps, carcass clamps, whatever you want to call them – that are mostly used to edge glue boards, clamp post and rail assemblies such as for a table, and glue up carcasses. This discussion refers to clamps where the contact part of the head starts right at the bar; not F style clamps.

I used 3/4″ pipe clamps for this for a long time – too long. They have the advantage of economy, especially because longer clamps are made by simply swapping the heads onto longer pipes. However, even with special supports and pads, they just cannot be used with the same reliable precision as parallel-head bar clamps.

Precision? For clamps? Yes. At crunch time, clamping precision matters. We use precision tools like squares, pinch rods, and straightedges to accurately assess a case or leg-and-apron assembly, looking for tiny gaps and misalignments. Doesn’t it make sense to invest in accurate tools to adjust and hold those parameters at the moment when it really counts and when there’s no going back?

As with most topics on this blog, I will tell you what I use and why, hoping this will be helpful to readers making choices and solving problems in their shops. I cannot offer comprehensive comparative reviews like in the magazines, just real stuff from years in my shop.

My favorite parallel clamp is the Jet. Bessey also make excellent clamps – I have some of their older model – and there are others including Jorgensen and Irwin. An alternative is the aluminum bar clamp by Universal Clamp Company, which is a precise clamp with the advantage of much lighter weight. Though a good choice for lighter work, these eventually lost out in my shop to the more versatile Jets, which are more rigid and deeper.

To open the Jet clamp, the head is released to slide freely without catching by lightly pulling up on a lever under the handle. The head can be advanced to close the clamp without using the lever. I really like how the thread action engages immediately when the head is set into position. There is no lag or confusing need to lift or lower the handle for any of this.

The long side of the firm, glue-resistant head extends more than four inches. In some situations, the work piece can also be placed on the side of the bar or under the short side of the head where there is about ⅝” extension. I like the large diameter handles that give good moment when tightening. To really sock down, use grippy gloves.

The inch scale on the bar is handy when readying a bunch of clamps, such as in edge joint glue ups. There is also a simple moveable support for the bar.

More to come on clamps and clamping.

I guess I can’t quite leave sharpening alone. About six months ago I switched to using a Naniwa Chosera 10,000 as my primary finishing stone.

I had been using a Shapton 16,000 glass stone for this purpose and could have left well enough alone because it is an excellent stone. It’s fast, the grit is very consistent, it’s convenient because it requires no soaking, and it gives a great edge. However, the drawback for me has always been the lack of excellent tactile feedback from the blade on the stone surface.

This is particularly important for freehand or semi-freehand finishing of the cambered edge of plane blades where the feel of the edge on the stone is critical. Even when using a honing guide for simple non-cambered edges, the delicate feedback near the end of honing is helpful and reassuring that the angle and edge are right.

I had read reviews claiming the feel of sharpening on the Chosera 10K stone was outstanding and that is just what I have found. That’s the big difference and it really matters. Moreover, it cuts just as fast as the Shapton, maybe faster, but is practically more efficient because I have fewer do-overs. There is also no tendency for the blade to skip as on the fine Shapton.

The Shapton is 16K and the Chosera 10K, so does this mean a step down in edge quality? Grit number is just one factor is producing edge quality. Others include the particle shape and how it fractures, the consistency of particle size, the density of the particles and how they present at the surface, and the properties of the binder. In practical shop use, the Chosera has been producing edges not one bit less sharp or otherwise of lesser quality than the Shapton. In fact, I think it’s better, if only because I can better feel those last whispery kisses of the sharp edge on the stone to get it just right.

The minor downside of the Chosera is that it needs pre-soaking. Various recommendations can be found for this including that soaking is optional. I’ve found it needs 15 minutes. Less soaking, 5 or 10 minutes, makes the stone too quickly drink up the water you splash on when starting to sharpen. When finished sharpening, I flatten it while it is still wet with the Shapton diamond lapping plate.

I still use a 1200 grit diamond stone as a nagura and remain convinced this enhances the action and feel of finishing stones including the Chosera 10K, as well as the quality of the finished edge. (More to come on this soon.) I did not find helpful the nagura that comes with the Chosera.

This is an expensive stone but at more than one inch thick, it will last a long time. The bottom line is that it has made my sharpening more assured because of the excellent feel.

With their new line of customizable hand planes, Lee Valley/Veritas continues their impressive record of innovation in woodworking tools. Within each plane size, you can choose the blade steel, the handles (thankfully), and the frog.

The most compelling option, in my view, is the choice of frogs, and particularly in a smoothing plane. This gives us yet another way to vary the attack angle. This is simply how high is the angle (from horizontal) of the top surface of the blade at its very edge. In other words, it is the angle at which the blade meets the wood. This is one of several factors, a critical one, in reducing the dreaded tearout of hand planing.

Let’s look at the mainstream options for attack angle that we’ve had so far

In bevel-up bench planes, the blade is usually bedded at 12°, though I continue to assert that 20° – 22° would be better. The attack angle is determined by the bed angle plus the sharpening angle of the most distal bevel, usually a secondary or micro bevel. For example, a blade with a 38° secondary bevel sitting on a 12° frog, gives a 50° attack angle.

By maintaining multiple blades or re-honing a single blade, you have your choice of attack angles. By the way, because the wear occurs more on the bottom surface of the blade, the Charlesworth “ruler trick” is especially helpful when sharpening bevel-up blades.

In bevel-down planes, most are made with 45° frogs but Lie-Nielsen offers a choice of 45°, 50°, and 55° frogs for most of their great bench planes. I like the 50° frog in my L-N #4 smoother. The attack angle in a bevel-down plane is usually determined simply by the bed angle. The nifty exception is the back bevel, which is a tiny bevel on the (otherwise) flat side of the blade. For example, in addition to conventionally sharpened blades for my #4, I keep one prepared with a 10° back bevel to produce, with the 50° frog, an attack angle of 60°.

What’s new

Now Veritas, with their awesome manufacturing capabilities, offers a full range of bevel-down planes with your choice of frog angle from 40° to 65° in 0.5° increments. Furthermore, extra frogs can be ordered that can be easily swapped into your plane. So, you could outfit your #4 smoother with a 45° frog and an O-1 blade for a project in pine, then swap over to a 57.5° frog and a PM V-11 blade for a project in figured maple. The caveat is, of course, that I haven’t used these new planes so I cannot judge if their innovative design actually performs well at the bench.

All of this means we have more choices and a greater, though happier, burden of choosing. Obviously, each of us does not need or want every tool and option available, so it is more important than ever to make intelligent choices in tools.

Let’s explore a simple method to verify the alignment of jointer knives, which is necessary when changing or adjusting them.

The first goal is to have all of the knife edges across their full widths in a consistent relationship to the outfeed table. The top of the arc of the knife edge should be very slightly above the level of the outfeed table. Secondarily, perhaps after the edges wear down or the jointing performance needs adjustment, the overall height of the outfeed table can be tweaked.

There are several good approaches to dealing with this, some involving dial indicators and specialized accessory equipment, but I prefer a low-tech method. Though well-known, how accurate really is it?

Here is how I perform the test, starting with unplugging the machine. A block of wood, about 3/4″ thick x 1 1/4″ x 4 ½” long is carefully jointed (by hand) and marked with 1 mm gradations. As you can see, I like to label the jigs I make with a description and reminders. It is placed in a reference position on the outfeed table (photo above, at top).

Then, the cutterhead is carefully rotated by hand to allow the knife edge to “grab” the block and advance it through the portion of the edge’s arc that is above the level of the outfeed table. The block is deposited as the edge “lets go” and continues its arc below the level of the outfeed table. (Photos below.) Note that a wooden test block is better than a metal ruler, which the edge doesn’t grab well.

The beginning and end of this arc define a tiny chord of the knife flight circle. The height of this chord is the amount of projection of the knife edge at its highest point above the outfeed table. The test is repeated at three or four places across the width of each knife.

Now let’s correlate this height with the lateral travel of the test block, which is the length of that tiny chord. A mathematical formula involving the Pythagorean theorem gives the results, tabulated below, for the 72 mm cutterhead knife flight circle on the Hammer A3-31.

Knife

Projection       Chord          Chord

(inches)          (mm)          (inches)

.0005             1.9             .075

.001               2.7             .106

.002               3.8             .151

.003               4.7             .184

.004               5.4             .213

.005               6.0             .238

.006               6.6             .261

The method is very accurate! A mere .001″ of knife projection moves the block 2.7mm, which is easily distinguishable from no movement, which signifies no projection.

However, note that the relationship of the knife projection to the advancement of the test block is not linear. The first thou of height advances the block 2.7mm – about 3mm. However, a height difference from .002″ to .003″ only advances the block about one more mm (0.9mm).

Fortunately, I want the knives to be a only about one thou, two at the most, above the outfeed table so all I have to do is see that the block advances about 2-3 mm, or 4mm at the most, and do so reasonably consistently across the blade width, for all of the blades. Indeed, the Hammer manual recommends 2-3 mm of travel.

So, there it is: a low-tech, accurate method. But now, after having analyzed it a bit, I have more confidence in it and can use it more intelligently.

This final installment in the series will discuss changing blades in the Hammer A3-31 and some summary thoughts on jointer-planer combo machines. [The entire series can be viewed here.]

With some jointers and planers, changing blades is a tedious chore. Long ago, I struggled with the old spring-loaded jackscrew system on a jointer. Brutal. By contrast, changing blades on the Tersa cutterhead that was in the Inca jointer-planer was almost unbelievably easy and fast. The OEM system on the Dewalt DW735 planer was quite easy, and now with the Shelix cutterhead with carbide-tipped inserts installed, changing blades is practically a non-issue.

The system for changing and adjusting the blades on the A3-31 is very good, though not quite the slam dunk of a Tersa. Each of the three blades has holes that neatly register on bosses on the blade holder, which is secured in a slot in the cutterhead with four hex socket screws using the provided T-handle wrench. (See the photo above.) This is easy to do, though a cutterhead lock would make it easier.

If necessary, the blade holder-blade assembly can be adjusted for height with the four adjustment screws within the holder block. These can be used to make a consistent projection of the knife in relation to the outfeed bed across its full width. Further, the height of the outfeed table is adjustable to set its overall relationship to the arc of the knife edges.

The factory settings, which I assessed when the machine was new and the knives were fresh, were excellent; no changes needed! So, when I installed replacement knives, everything should stay the same, right? Well, it worked out pretty well, maybe actually well enough, but not quite to my satisfaction. Somehow, despite great care on my part, gremlins sneaked in and I had to fiddle with the height adjustment screws to get an a consistent projection across the width. (This is not a matter of a difference in the overall projection related to worn versus fresh knife edges.) The manual explains a simple assessment procedure to help get it right and I am happy with the results. Note that perfection is not necessary for this. By the way, another option is the helical insert cutterhead available for the A3-31 from Hammer.

Here’s the key: the machine performs accurately, consistently, and efficiently. I get the results I need to make high quality things from wood. This is what matters.

In summary:

1. For the reasons explained in this series, I highly recommend a 12″ jointer-planer combination machine for the small shop woodworker.

2. After 2 1/2 years experience with the Hammer A3-31, I heartily recommend it. As with any machine, there are a few shortcomings (for this fastidious woodworker), which I’ve covered, but this is an excellent machine that can be a great partner as you pursue excellent woodworking. I cannot fairly compare it to corresponding offerings from Minimax, Jet, Rojek, Grizzly, and Rikon because I haven’t used them, and I’d bet the $7,000 Felder AD-531 outshines all of these, but I can say I’m very glad I have the Hammer A3-31.

Now for a look at the parts and systems of the Hammer A3-31 that can be adjusted and tuned, with particular consideration to the ease, accuracy, and durability of the adjustments.

Jointer beds

When the machine arrived, the beds were slightly out of parallel to each other across their widths (i.e. in twist) – by .006″ over the 12″ width. Not bad, but having seen the potential in the excellent flatness of the beds, I wanted to improve their alignment.

Since the alignment of the outfeed table to the knife arc was fine from the factory, the twist was easily removed by adjusting only the two bolts (see the photo above) on the operator side of the infeed table to make the tables parallel within .001″.

Next, using a long straightedge, I determined that the infeed and outfeed beds were tipped along their lengths toward each other. The gap at the middle was 0.018″. To my mind, this is like have a concavity along the full length of a jointer plane sole and would make accurate jointing difficult at best.

Again, the correction was made by adjusting only the infeed table. This was a more complicated adjustment involving the pair of bolts on the operator side and a pair of setscrews, accessed under a removable panel, on the hinge side. Each of each pair of screws must be adjusted by a different amount. To make a long story short, I did a little trigonometry to prevent having to do it by trial and error. The result: cha-ching! The beds are parallel along their length within .001″.

Unfortunately, the Setup Guide, which covers these adjustments and is available as a pdf on the Hammer website, is out of date (copyright 2005). It references an earlier design of the machine and much of the adjustment parts have changed. Fortunately, Hammer makes knowledgeable technicians available by phone who were generous with their time in helping me understand the machine.

I called Hammer this week in anticipation of this post, and they favorably received my suggestion to update the Setup Guide. The User Manual, included in print with the machine and also available online, is more current and clearly explains assembly, basic adjustments, operation, maintenance, and so forth.

Planer bed

I tested this on a performance basis by planing an 11 3/8″-wide board, and by planing two narrow sticks simultaneously sent into the planer at the outer width of it. From the factory, the planing parallelism was within one thou. Wow! This is adjustable if ever needed.

Digital handwheel

This accessory, which I have found very helpful, was calibrated using the information in the Setup Guide. Reading it takes a bit of getting used to because the numerals indicate decimal inches while the hash mark increments are actually metric that approximates imperial. It is really not a problem though.

Fence

Setting up the fence accurately went according to directions, though it does take some care. To maintain a consistent angle, it is important when adjusting the side-to-side position of the fence in use to hold the sliding bracket down firmly on the extruded track while tightening the knob.

In summary, the A3-31 can be tuned to a high degree of accuracy. There are some finicky steps for those who want to tune it really well. Some documentation is lacking but help is available.

The most welcome feature is that the adjustments hold solidly over time and when converting back and forth from jointer to planer mode. This is invaluable.

Next: one more installment – knife changing and an overview.