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Perspective View of Modeled Wing SkinA reader asked whether airplane wings could be modeled in SketchUp. Without ever having tried I confidently answered “anything can be modeled in SketchUp”.

I am an instrument rated private pilot and the question intrigued me.  I wondered how one might go about modeling a wing. So later that day I set about to develop a proof of concept. The result is shown at right. This proof of concept, or first attempt, has a number of flaws so I decided to take it to another level. In this article I will describe in layman’s language the major design parameters and trade-offs the aeronautical engineer makes when designing a wing and then I will show you hot to model it. Let me make very clear that I am not an aeronautical engineer; the definitions and explanations I give here are my lay interpretations of things I have read over the years. If you are an aeronautical engineer and take issue with anything I say please correct me by commenting to this post. That way all readers can benefit from your feedback.

I have two simple SketchUp models the reader can download for self manipulation.

http://www.srww.com/blog/wp-content/uploads/2012/11/Wing1.skp

http://www.srww.com/blog/wp-content/uploads/2012/11/Wing 2.skp

Before proceeding some definitions are in order:

Airfoil – Airfoil is the cross section of the wing sliced by a plane parallel to the plane formed by the plane’s longitudinal and vertical axis. The airfoil generally has a positive camber on the top surface, is thicker near the front edge than back edge and the leading edge is smoothly curved approaching a semi-circle.

Ailerons

Control surfaces located at the trailing edge of the wing near the wing tips. Surfaces move in opposite direction (one up and the other down) to produce roll around the longitudinal axis of the airplane.

Airspeed

The speed of an aircraft relative to the air surrounding it.

Angle of Attack (AOA)

The angle between a wing’s chord and the direction of flight (a vector parallel to airspeed).

Chord

A straight line running from the leading most point on the leading edge to the trailing most point on the trailing edge.

Drag

Forces opposing the direction of flight. Drag has two components: parasitic drag, caused by skin friction such as ice accumulating on a wing; induced drag, caused by flight attitude such as high angles of attack.

Flaps

Control surfaces located at the trailing edge of the wing near the wing roots. Surfaces are angled down in steps. Each step produces more lift until the increased drag slows the airplane to a stall speed.

Mach

Mach 1 is the speed of sound; Mach 0.6 is sixty % of the speed of sound and so on. In dry air at 20 °C (68 °F), the speed of sound is 343.2 meters per second (1,126 ft/s).

Planform

The view of a wing looking down its vertical axis.

Stall

A point reached when the airfoil no longer produces sufficient lift to overcome weight and is produced by angles of attack greater than the stall angle. Stall can be abrupt and dangerous. Essentially the wing stops flying.

Sweep

Wing sweep is usually the counterclockwise rotation of the wing in the planform view. The major advantage is to high performance planes flying near or above Mach 1; wing sweep helps to increase the maximum airspeed of the plane.

Taper

Taper can be applied to the leading edge, trailing edge or both. Wings are generally tapered such that the chord is shorter at the tip than at the root. Taper should not be confused with Sweep. The major advantages of wing taper are: reduced weight, structural integrity (lower bending moment), reduces drag. A disadvantage of wing taper is that it reduces the AOA at which stall occurs at the tip and hence may have poorer stall characteristics.

Twist

Generally a wing has lower angle of attack (AOA) at the tip than the root. The AOA usually decreases linearly from root to tip. This type of twist is used to ensure the wing stalls first at the root and last at the tip where the control surfaces are.

Wing Setting Angle

Wings Setting Angle (also called wing incidence) is the angle between the fuselage center line and the wings chord line mapped on the y-z plane (plane of symmetry). You can think of it as a built in AOA which helps to increase lift at slow speed such as during the take-off roll and climb. Typical wing setting angles are 0° – 5°.

The Airfoil and Bernoulli’s Principle

bernoullilYou probably remember basic airfoil (hydrofoil in a fluid) theory from your high school physics class. Airfoils and hydrofoils operate on the Bernoulli principle which says that as a fluid increases in velocity it is accompanied with a decrease in pressure. You have seen this in action many times in your daily life. As you drive a pickup the air flows over the top at a speed roughly equal to the speed of the vehicle. The air behind the back window, in the bed of the truck, is still; not moving at all. As a result things sitting in the bed often are lifted up toward the fast moving air overhead. Indeed, the whole backend of the truck experiences some lift and makes the back of the truck a little “lighter” creating problems for the driver in wet or icy conditions.

angle_of_attackThe airfoil takes advantage of this phenomena (or more accurate one of the many laws of physics). You have probably experimented with a sheet of paper as an airfoil. If not, hold a piece of printer paper between the thumb and forefinger of your right and left hand at the end of the paper. Pull on the paper to take out the slack at the end. The rest of the paper will fall limp. Bring the paper to your lips with your lips just above the paper. Now blow steadily and easily. Notice the paper lift slightly. Now blow steadily and harder. Notice the paper lift more. The harder you blow the more the paper lifts. This is the Bernoulli principle at work. Fast moving air on the top side of the paper produces lower air pressure and results in lift being produce in the direction of high pressure (beneath the sheet) to low pressure (above the sheet).

The airfoil of an airplane wing (and many bird wings) is wider in the from with the front edge being round or curved, and tapering to a very thin edge at the back. The top surface generally has a camber and the bottom surface is generally flat. See the second image above. Oncoming air is moving at the air speed of the airplane and separated at the leading edge. As air that moves over the top must travel a longer distance to meet up with the air moving beneath the wing, it must must travel at a faster speed than the air on the bottom. Therefore the relative pressure is greater above the wing and hence lift is produced at the bottom of the wing.

In the second image above you will notice that while the distance air must travel at the bottom is less than at the top, it is still greater than the straight line distance from leading edge to back edge. Aeronautic engineers often build in a slight angle to the airfoil, called angle of attack. This has the effect of decreasing the distance that must be traveled on the bottom, and hence increases the top edge distance. This means the resulting total lift will be greater. However, if the angle is too large the face of the bottom of the wing will be presented to the oncoming air and produce excessive drag. So there is a delicate balance that must be achieved. See the third images above. Notice that the total lift is still perpendicular to the bottom surface of the plane (oversimplification) and now has components of airplane lift and drag. Airplane lift is opposite the pull of gravity while a small amount of drag tries to slow the plane and is opposite the planes travel. If the angle of attack is optimum there is sufficiently small drag such that the airplane lift is still larger than if there were no angle of attack.

This description of lift doesn’t mention downwash at the trailing edge of the wing. This downwash assists in generating lift. Lift is a complex issue when thoroughly treated and has many components. My description is admittedly simple, but still useful for basic understanding.

Modeling the Airfoil

airfoil#0_dimensionsDrawing on my early pilot training on wing design I started with an airfoil profile; essentially the cross section of a wing. Airfoils come in many shapes. In this article I am modeling a basic airfoil which only requires three steps. The picture at left shows the three perimeter portions of the airfoil. I start with a semi-circle to the left of points a and b with a radius of 12” (2 foot diameter). At the bottom of the semi-circle I extend a line 96” (8 feet) from point b to c. From a to c I use the Arc tool with a Bulge of approximately 6 5/64” (a radius of approximately 204 17/32”. The dimensions of this airfoil may not be efficient, indeed may even be a poor design. However, it does have all the characteristics necessary for flight: the front edge is smooth and curved, the trailing edge comes to a point, and the air must travel a greater distance on the top surface than it does on the bottom surface. This is a basic but not atypical airfoil. When completed I make this airfoil a component called Airfoil#0.

Modeling the Wing Setting Angle

At this point a wing setting angle can be modeled by simply rotating the airfoil around an axis perpendicular to the airfoil surface and running through the tails trailing edge (point) See the third image in this article.

General aviation airplanes have wing setting angles of 2° – 4°. Commercial airliners may have wing set between 3° – 5°. Supersonic fighters have very shallow wing set between 0° – 1°. Flying wings are considered to have no set because they have no fuselage.

The wing I modeled here has an exaggerated 8° wing set to make it more visually apparent in my images.

Tapering Wings for Stability and Structural Strength

extruding_the_airfoil

Wings are often tapered so that they are smaller at the tip than they are at the fuselage. Lift generated at the tips of the wing have much more influence (torque – ft-lbs) on the plane around its longitudinal axis than lift near the fuselage. The ailerons are placed near the tip of the wings and to manage aileron response stability the wing tips are tapered and hence produce less total lift.

Creating the wing shape is a series of tedious steps, one which would benefit from a Ruby script, which I might write one day but not for this article. First I need to create a number of airfoils; remember an airfoil is a cross section of a wing. So I need enough cross sections, evenly spaced to give me a smooth wing shape. My wing, when finished, will be approximately 35’ in length so I arbitrarily choose to create 33 additional airfoils, spaced 1’ apart, and each one smaller by a factor of 0.98. Also, when done I want the trailing edge to be a straight line. To do this I use a combination of the Move/Copy, Scale and Make Unique tools thirty three times (this is where a Ruby script that recorded a sequence of steps and repeated them N times would help). First I use the Move/Copy tool to copy and move the previous airfoil to the left one foot. Next I use the Scale tool to uniformly scale about the opposite point a factor of 0.98. The “opposite point” is the point at the trailing edge. This will keep the trailing edges lined up along a straight line. Finally I use the Make Unique command on the Context menu to make a new component, each sequentially numbered. I now have thirty four airfoil components named Airfoil#0 through Airfoil#33.

Wing Twist to Improve Stall Characteristics

Many wing designs include wing twist; gentle continuous rotation of the wing along it length. The direction of twist has a profound effect on the planes stall characteristics. If the wing is twisted counterclockwise, when viewed from the tip and looking at the root, the wing tip will have a lower angle of attack than the wing root. Recall that wings stall – wing stops flying – when the stall angle is reached. Once the wing stops flying the pilot has little or no control of the plane.

Wings with twist don’t stall at the same time along the wings length, rather the roots stalls first because it has a larger set angle than the twisted wing’s tip. Hence stall progresses from the root outward to the tip as the AOA increases.

Ailerons, the roll control surfaces, are located near the tip of the wing. So it is desirable for the tip of the wing to remain flying (not stalled) as long as possible when the planes angle of attack reaches the stall angle. Wing twist assures this occurs.

wing_twistModeling twist is a simple matter, though a tedious one, of reducing each airfoil’s set angle a fixed amount relative to the previous one starting at the root and working toward the tip. In the case of the wing I modeled here, Airfoil#0 has a set angle of 8°. Each following Airfoil has a set angle reduced from the previous by 0.2° resulting in Airfoil#1 having a set angle of 7.8°, Airfoil#2 7.6°, Airfoil#3 7.4° down to Airfoil#33 1.4°.

In practice this can be modeled by selecting Airfoils #1 – #33 with the Select tool. Reduce their set angle by 0.2°. While all 33 airfoils are still selected use the Select tool with the Shift key to deselect Airfoil#1 leaving Airfoil#2 through Airfoil#33 still selected. Now use the Rotate tool to reduce the selected airfoils set angle by 0.2°. Now deselect Airfoil#2 leaving Airfoil#3 through Airfoil#33 still selected and reduce their set angle by 0.2°. Repeat this process for each airfoil down to and including Airfoil#33.

Airfoil#33 will have a set angle of 1.4°. Starting with Airfoil#0 with a set angle of 8° and subtracting 33 reductions of 0.2° equals 1.4°. The finish twisted will will look like the image at above left.

Modeling the Wing’s Skin

wing_skinWe now have the airfoil cross sections and we can use them to create the wing. I only model the skin in this article; not the internal structure called spars and ribs. Nor do I give the skin thickness. These can be modeled quite easily once the airfoils and skin have been modeled, and I will leave that exercise to the student.

Recall that the beginning airfoil was constructed with a semi-circle, straight line and an arc. SketchUp models circles and curves with line segments. Each line segment has endpoints which the inference engine will point out when you hold your cursor over it. I connected these endpoints with straight lines to produce the mesh of rectangles shown in the picture above right. Again this is tedious and repetitive but doesn’t take too long.

triangulated_wingIf wing twist is modeled the above process gets even more tedious. With wing twist no four points will form a plane – the wings twist ensures that. So the skin must be modeled with triangles; three points will always form a plane. The image at left shows the hidden geometry of a twisted wing.

Note that the wing tip is modeled using the Follow Me tool to create and one quarter sphere, then using the Push/Pull tool to extrude the one quarter sphere and finally using some hand stitching and cleanup.

Swept Wing Design for Higher Air Speed

Swept wings should not be confused with tapered wings described above. Wings are swept – angled toward the tail – on high performance planes including corporate and airliner planes. The reason is simple; swept wings allow a plane to fly faster. How a swept wing works is not simple and in-depth understanding requires a degree in aeronautical engineering. I will attempt a significantly oversimplified explanation to give you some basic understanding.

sweepAs a plane approaches the speed of sound, Mach 1, there is a speed lower than Mach 1 where, due to the complex shape of an airplane, some parts of the plane reach Mach 1. That is some areas of the plane reach Mach 1 before the plane’s airspeed is Mach 1. Shock waves appear at those points and produce drag rather abruptly and increases rapidly. These shock waves limit the speed the plane can fly. The critical Mach number (Mcr) of an aircraft is the lowest Mach number at which the airflow over some point of the aircraft reaches the speed of sound. This might be a number such as Mach 0.75. To increase the speed of the aircraft the aeronautical engineer has to increase the effective Mcr. Enter the swept wing.

The Mcr of a non-swept wing is a function of the airfoil design; principally the chord line of the airfoil cross section. Before a wing is swept the chord line is parallel to the travel of the airplane and aligned with the planes airspeed. When the wing is swept the chord line is at an angle to the airspeed. The airspeed now aligned with the cord line is a fraction of the airplanes airspeed, and is proportional to a leg of the right triangle of which the chord line is the hypotenuse and the angle between the hypotenuse and leg is the sweep angle. Now the airplane can accelerate to a higher airspeed before the airspeed component parallel to the airfoil chord reaches Mcr.

As stated earlier, this is significantly oversimplified. Not all of the theoretical advantage of sweeping a wing is realized because of other effects such as skin friction and fuselage drag. In fact some supersonic aircraft do not use swept wings, such as the Lockheed F-104 Starfighter which reaches airspeeds of Mach 1.7 with straight wings.

Modeling wing sweep is a simple matter of using the Rotate tool to rotate the wing around a pivot point near or at the root. This angle is usually small but can be aggressive and deep on high performance military aircraft.

Dihedral Design for Roll Stability

dihedralAnother very important design property is dihedral. Some plane wings slant up at the tip (dihedral) and some slant down (anhedral). When dihedral is designed into a plane wing it increases roll stability (stability around the longitudinal axis). Cross wind gusts tend to push one wing down (or the other up). When this happens the lower wing has a greater attack angle and presents more surface area in the direction opposite gravity. This cause the lower wing to produce more lift which opposes the rolling effect of the wind gusts. Dihedral is often used on small general aviation aircraft because this built in stability is rather inexpensive and tends to keep the inexperienced private pilot out of trouble. Anhedral is sometimes used on high performance planes for other advantages, but it is less stable. However, high performance aircraft have expensive and extensive computer sensors that can detect wind gust roll and generate computer controlled responses that can increase stability.

Modeling dihedral, like sweep, is a simple matter of using the Rotate tool to rotate the wings up around a pivot point near or at the root. The angle is usually small, maybe 5° or so.

Completed Wing Skin Model with All Major Attributes

completed_wingAfter modeling all the major attributes of a wing skin I ended up with the image at right. I used the Eraser tool with the Ctrl key to hide most of the lines including diagonals. The remaining lines simulate the edges of the aluminum sheets a wing skin is made of.

If I were an aeronautical engineer designing a real wing I would use this skin to model the spars, ribs, aluminum sheet thickness, rivets, ailerons, flaps, fuel tanks, wing tip lighting and so on. My purpose here was to point out the type of modeling techniques one might use to model a fairly complex shape.

This modeling task included a fair number of tedious and repetitive steps that would benefit from a Ruby script to produce Macro capability (memorize a sequence of steps and repeat them 1 to N times). Writing such a Ruby script would take much longer than executing the tedious modeling, and I doubt I would find the tool useful in many of the models I tend to work on. So overall it would be a waste of time. Modeling is often like that; it often pays to do things the simple and tedious way.


Headquarters In Warren,MEIf your experience is anything like mine you are tired of the companies that intentionally avoid human contact and feedback. I curse those telephone ladders that never lead to a human voice. When a human does answer you are speaking to someone who’s English is their second language and you have no hope of understanding them.

If you are lucky enough (some call it unfortunate enough) to make it through all that, and explain your problem with the company’s product, you are likely to be sorry you ever contacted them. You are treated to onerous procedures put in place to avoid correcting the situation. Some companies are honest enough to simply say “we don’t support our product with replacements” or “the problem is of your making and we can’t support you”.

LN's family of planes and accessories on display in the showroom.Not Lie-Nielsen. You see, Lie-Nielsen was somehow created from an old company mold; a mold I thought was broken and lost a long time ago. They talk to their customers, never fearing to meet them and listen to their feedback. In fact their factory is open to customer visits on most days (see my visit to the factory). They even have an annual Summer Open House where you can meet and talk with the entire staff including Tom Lie-Nielsen and family. And for a small fee you can enjoy a lobster bake dinner.

Not only does Lie-Nielsen talk to their customers, but they also surprise their customers with above-and-beyond support. I dropped my #5 Jack recently and broke my tote. I went to the Lie-Nielsen website to purchase a replacement. Disappointed not to see a replacement part I emailed the company. I want to share with you two emails, unedited; one that I sent to Lie-Nielsen and the return email.

To: toolworks@lie-nielsen.com
Sent: Wed 5/23/2012 5:23 PM
From: Joe Zeh [jpz@srww.com]
Subject: Jack Plane Tote

Hi,

 

I dropped my #5 Jack Plane and broke the tote. Fortunately I have a wooden floor in the shop and nothing else broke. Do you sell replacement totes?

 

Joe…..

 

From: Lie-Nielsen Toolworks [mailto:toolworks@lie-nielsen.com]
Sent: Thursday, May 24, 2012 2:41 PM
To: jpz@srww.com
Subject: RE: Jack Plane Tote

Good afternoon, Joe.

I am sorry to hear about your No. 5!  Fortunately in situations like this, we can supply you with a replacement handle at no charge.  I’ll have one sent out to your address today.

Thank you,
Kirsten

Kirsten Lie-Nielsen
Lie-Nielsen Toolworks
1-800-327-2520
www.lie-nielsen.com

The Lie-Nielsen No. 4 Bronze Bedrock Smooth PlaneLie-Nielsen didn’t simply replace my broken tote, which I freely admitted was due to my mishandling, but look at who replied, and note the cheerful and helpful voice of that reply. OK, Lie-Nielsen is not a multi-billion dollar corporation, and so you might argue that a multi-billion dollar corporation can’t afford to do these things. To that I would ask you to compare this customer’s response to Lie-Nielson in this situation to the same customer’s response to a new Grizzly G0586 8" Jointer. It is in a company’s best interest to support its customers – its peril when they don’t.

I have bought many Lie-Nielsen hand tools- and even a bench – over the years. Their trademark exceptional quality has always been present in those tools. When I told my wife about this situation she replied “Unfortunately, people need to understand that they have to buy, and pay for, quality up front instead of expecting a free replacement part for a plane they get at Wal-Mart.”.  It’s true. If you buy an object based on lowest cost you will replace it numerous times over your lifetime. On the other hand, you can buy a Lie-Nielsen plane, have it for life, and pass it on to your children and them theirs. Quality is always the best, and cheapest, investment.

A group of No 4 ½ Irons and Scrub Planes ready to be packaged and shipped.As I said, I have been buying Lie-Nielsen tools for some time and will continue to look first at Lie-Nielsen when again in the market. Not just because of their exceptional quality and customer consciousness, but they are Made-In-America. This is not a political site and never will be. But I sure wish our leaders would figure out what Tom Lie-Nielsen knows; it is in this country’s best interest to make real, physical things.

Lie-Nielsen, you have my respect and my business.


Finished Panels With 3 Coats Of Wipe-On-Poly Picking up from where I left off in Trundle Bed Crafting – Part 1, I finished all five panels. Three panels will be framed in the headboard and two in the footboard. Just like panels in frame-and-panel construction you must add a few coats of finish to the panels before encasing them in their frame. If this step is skipped unsightly unfinished edges are visible as the panel expands/contracts through seasonal changes.

Trundle Bed Shown With The Trundle Out The next step in Trundle Bed Crafting is to tackle the swan necks that top the headboard. I began by printing out a full scale SketchUp drawing of one swan neck. They are mirror images of each other so all I need is one paper template. However, the swan necks are constructed with two layers glued together and the result is a 3 1/4” piece of stock. Since I need to shape four pieces, all with the same top curve, two of them share the same bottom curve, and two have a bottom curve that is 3/4” away from and smaller than the other two, I decided to make one hardwood template. Using the paper template I traced it onto 3/4” thick cherry stock being careful to arrange the grain for best strength. I rough cut the template on the band saw and completed the shaping on the edge sander.

Completed Swan Neck Cherry Template The completed cherry template, shown left, will be used in a series of steps with template router bits. The Swan Neck presents a number of interesting challenges for the woodworker. The first one is its thickness. The Swan Neck is 3 1/4” total thickness made of a sandwich of a 2 1/4” back and 1” front. I designed it as a sandwich to make shaping easier and doable with my current collection of shaper and router bits. But even the back is wider than my longest 2” template bit.

The Cherry Template Is Traced On 2 1/4" Thick Stock Fortunately I have two 2” template bits; one with a bottom bearing and one with a top bearing. So I used a three step procedure to shape the Swan Neck backs. I traced the cherry template on 2 1/4” stock. I needed two of them and they need to be mirror images which was simply a matter of flipping the cherry template.

Rough Cutting The Thick Back On The Band Saw The first step in this three step procedure is to rough cut the thick Swan Neck back on the band saw. My band saw had a 1 1/4” re-saw blade mounted in it and I should have replaced it with one much narrower allowing me to follow the curves smoothly. But being lazy I simply hacked away at the stock with the re-saw blade. You can see the resulting burn marks created by a 1 1/4” blade struggling to follow comparatively sharp curves. But with no damage to the blade I was able to cut to within 1/8” of the outline making the job for the template router bit minimal. When I was done I had Side A and Side B of the Swan Neck back and the template.

Shaping All But Top 3/4" Of Swan Neck With Bottom Bearing Template Bit The second step in this three step process it to attach the template to the appropriate side of the one of the Swan Neck backs. Appropriate side means keeping the side labels matched, for example Side A facing up on both, but with the template on the bottom. I attached the cherry template to the Swan Neck back using double sided sticky tape (carpet tape). In this step I use the bottom bearing template bit and with the template as a guide and shape all but about 3/4” of the Swan Neck as shown at right.

Complete Shaping With Top Bearing Bit In the third step of this process I replace the bottom bearing template bit with a top bearing template bit, remove the cherry template, turn the Swan Neck over and use its partially shaped surface as a template. See the picture at left. I have to use this three step process on both Swan Neck backs. But I am not done; I still need to shape the Swan Neck fronts. However, they are only 1” thick and only require rough cutting and one template bit. But there are still some tricks that need to be employed to complete the Swan Necks as you will see in Trundle Bed Crafting – Part 3.


A reader wrote me in the comment section of one of my blogs and asked how I like the Performax Pro 22-44 drum sander. He was considering purchasing one and wanted my opinion. I replied “I can’t say enough good things about the Performax Pro 22-44 drum sander”, and I can’t. So much so I thought I would write a post just about this invaluable tool.

This is not a power tool that gets used only on occasion – no sir. Nearly every board in my shop goes through it during at least one process step. Mostly immediately following the planner. I use it for final thicknessing of all parts using 80 grit paper. I may also use it for finish sanding of panels and other parts with 220 grit paper. This is especially true for stock that has grain direction changes that would cause tear out with a hand plane.

Bringing Door Stiles & Rails To Final Thickness My thicknessing process starts with the planner where the stock is brought to within 1/16” or 1/32” of final thickness. If the stock is figured wood such as tiger maple or blistered maple I may even leave the stock 1/8” over sized because tear out on figured woods can be excessive. I will then bring the stock to within 1/32” or 1/64” with the 80 grit paper on the Performax Pro. Depending on other factors, I may even bring it to final thickness with 220 grit drum paper.

The drum sander has five significant advantages over the planner for final thicknessing. First there is negligible to no snipe at the ends. Hence you can save two to four inches on rough stock lengths.

Second, small nicks in a planner or jointer blade leave noticeable ridges in the wood. This only happens on a drum sander if you have a burn in the paper from clogging (generally caused by pitch pockets). But the latter is extremely rare while the former is quite common.

Third, with fine paper you can attain the final thickness while also leaving the stock with a finished surface.

Fourth, you can finish figured woods with no tear out, which is nearly impossible on the planner.

Thicknessing A Wider Than 22" Panel After Glue Up Fifth, and this brings me to another feature of the Performax Pro in particular, is that you can thickness wide panels. The 22-44 in its name means you can sand panels as wide as 22” in single passes, or up to 44” in two passes. Note in the picture on the right that the panel hangs out the edge of the drum sander. Simply turn the panel around to sand the remaining portion.

This can be a little tricky on long and wide panels, for example, 30” wide and 72” long table tops. You must be careful to keep the piece moving and prevent it from drooping over the edge due to its weight. It helps to have a helper in such situations.

A Simple Leg Taper Jig One of the things about a drum sander is that it is relatively safe. You might get pinched if you are not careful but it is very unlikely that you would lose a digit or suffer a significant cut. In fact, if you use your imagination you can use the drum sander to de-risk otherwise risky shop operations. For example, tapering table legs can be a risky operation, particularly on a table saw. But you can taper legs on a drum sander very safely.

In the picture above left I have rough cut tapers on four legs using the band saw in free hand style (this is not a necessary step but one that makes things go quicker). No need to be accurate, just be sure to leave the taper line. Stay an 1/8” away from it if you are not confident about your free hand cutting ability with a band saw; or skip this step all together and do it all on the drum sander.

Tapering Table Legs With A Simple Jig & Drum Sander The jig is simple; use either 3/4” plywood, or as I have here, a Formica covered piece of particle board. Using double sided sticky tape place two pieces of 3/4” wood in the direction perpendicular to travel through the drum sander. Space them for the correct taper by sliding one board closer to or further away from the other until the taper lines are parallel to the jig surface. Place the rough taper legs as I have in the photo with one piece keeping the legs from moving beyond the end of the jig and the other providing the correct taper. You may wish to tape the top ends of the legs together to keep them from slipping sideways. Start with 80 grit paper and finish with 220 grit paper and feed the legs through while monitoring the taper lines. See photo at right above.

Finished Tapered Legs - No Sanding Necessary The finished legs are shown at left; they are completed and require no final sanding. I have found this method to be not only safe, but the final product is more accurate than when cut on the table saw. In addition there are no burn marks from the saw blade which is particularly troublesome with cherry. Lastly, any significant grain direction change is no problem for the drum sander, but might be for even a hand plane. These legs were made for an Office Table which you can read more about by gong to http://www.srww.com/office_table.htm.

Flattening A Panel After Glue Up Glue ups can create wide panels and no matter how careful you are the individual boards do not align perfectly. I generally leave panel stock 1/16” to 1/8” thicker than finished width. After the glue is dried I scrape any excess squeeze out from the panel and then draw numerous parallel lines on each side with carpenter’s crayon. I sand one side keeping an eye on the disappearance of the crayon marks. As soon as they are completely gone I turn the panel over and bring the opposite side to parallel. With 220 grit I then bring the panel to final thickness. See the picture at right.

Two things you need to know about this tool: One, you must have dust collection connected and running at all the times when you are using the Performax; Two, feed the material at half speed, using 1/8 turn on depth adjustment for each pass and don’t let the material stop. I have ruined several pieces of cherry when I first used the Performax Pro until I understood these issues.

One last piece of advice. If you do buy a Performax, it comes with a drive belt that moves the material which is similar to a sandpaper belt. Optionally they sell a rubber surfaced belt. Buy it. It’s worth the extra cost. The grip is better and it doesn’t mar your surface.

As you can see, the Performax Pro 22-44 drum sander is an invaluable and frequently useable tool. Not only does it do a better job in many situations, but it is often more accurate and safer. Its snipe free operation can result in less material used. And it can handle wide boards and panels that the planner cannot. It is the only tool that can handle figured or difficult wood without any chance of tear out. Even my trusty hand planes cannot guarantee that. This machine has been a workhorse in my shop and it is rugged and reliable. I wouldn’t hesitate a second to buy another if I found it necessary to do so. But I have a feeling this one will last so long that buying another will never be an option.


Well, I have finally started crafting the trundle bed I wrote about in the Trundle Bed Design series. Many family and unrelated projects got in the way of this project for some time. But no more excuses. The show must go on.

Headboard And Footboard Panel Details I decided to begin with building the panels for the headboard and footboard. The headboard requires a panel 22 57/64” tall by 40 1/2” wide and two panels 8 3/4” tall by 40 1/2” wide. The footboard requires two panels 8 3/4” tall by 40 1/2” wide.

The final thickness of the panels is 5/8”, but I prepare my stock for 3/4” and bring it to final thickness on the drum sander after glue up has been completed. This will allow me to take out any slight mismatches in the glue up joints which are unavoidable. In addition the drum sander can bring the finish panel to precisely 5/8” with 220 grit paper. That way, after shaping the edges, I can immediately apply several coats of finish, which I always do before affixing panels in their frames (The headboard and footboard are essentially a frame and panel construction.). Subsequent shrinkage of the panels will not reveal unsightly voids of finish.

Edges Are Always Prepared With A Hand Plane Before Glue Up Preparing stock for glue up requires the standard jointer, planner, jointer and table saw sequence to face and edge the boards. But the final step for me is always preparing the edges by hand with a hand plane. This accomplishes several things. First it removes any oils on the edge that exist from handling or are naturally secreted by the wood. This is especially important if the time from wood preparation to glue up is hours or days. Second the edge is given a glass smooth surface void of machine marks and scratches. Third I get a better edge, i.e. perfectly straight and square.

All these add up to a better looking and stronger glue joint. One of the tests I use for a properly finished edge is that I can get  a continuous, very thin shaving, of equal width all the way to the end, and the length of the shaving is the full length of the board. Notice the shaving above right. A Lie-Nielsen smooth plane is the one I use for the final cuts. But I will start with a jointer plane if the edge is close to straight, or a block plane if I have to cut short local areas to correct for a bow for example.

Headboard Panel Glue Up When I have finished preparing the edges with a hand plane I immediately glue up. If I have a number of panels to do, as in this case where I have five panels, I’ll prepare all the stock on the power tools. But only the edges for one panel at a time is prepared on the hand plane so that the time from edge preparation to glue up is short, keeping the edges from getting soiled or dinged.

I have tested glued edge joints numerous times and always found that a properly prepared and executed  joint will always be stronger than the wood itself. How long a joint will last I will never know because I won’t live long enough to see its failure. But the accelerated life tests manufacturers perform indicate these joints will still be going strong hundreds of years from now (barring abuse such as prolonged exposure to water, high heat or direct sunlight).

One other idiosyncrasy I have is that I always leave joints clamped overnight. True, the manufacture says you can work the wood after only one hour of clamping provided there are no undue stresses placed on the joint. But I am not sure what an undue stress is. This is an analog world we live in. Stresses don’t magically become undue at 10 lbs of force but not 9.9 lbs. So I am conservative but feel much more secure this way.

The Performax Pro 22-44 Is Used To Final Thickness The Panel After curing for an evening the panel is ready for final thicknessing. I do this on my Performax Pro 22-44 drum sander. To gauge when a side has been entirely sanded and flat I mark the panel with red carpenter’s crayon in wide horizontal lines. When the marks are completely gone I have succeeded in flattening the side. See the picture at right. I use 220 grit paper for this final step. I will sand it one more time just before applying finish with 320 grit and an oscillating rotary sander.

I am careful during glue up to put the good side of the panel up, i.e. away from the clamp’s bars. This allows me to clean the entire surface unimpeded by the bars of the the clamps. See picture above left. I clean the other side too, but the bars always obscure some glue. When dried the backside will have little glue hills which I level with a putty knife. Still, there is remaining glue to be removed. So the backside is the one I drum sand first. Then I turn it over, mark the good side and continue drum sanding until I reach final thickness.

On a panel this wide each pass actually requires two passes. As you can see in the picture above right, the panel is wider than my drum sander. The 22-44 in the name implies you can sand a 22” wide panel in one pass, or one as wide as 44” in two passes. One note of caution about drum sanders; you must not let the work piece stop while going through the drum sander. If you do the sander will sand a horizontal valley into your piece deep enough that you may not have enough thickness left to remove it.

Squaring The Panel On My Large Panel Cutter Once the panel is thicknessed I use a hand plane to create a square and straight reference edge. I then use that edge in my large panel cutter to square the panel to finished length. This panel cutter has been a life saver and workhorse for me. If you don’t have one I strongly suggest you make one soon. With it I can cut large panels (wider than a kitchen cabinet end panel) perfectly square every time, and with ease. The panel shown is 24” wide and 40 1/2” long. This panel cutter uses both table saw slots, has a high fence to keep your hands away from the blade and has a block that completely covers the saw blade as the fence passes it.

Inspecting The Panel With Mineral Spirits (Paint Thinner) When the panel is cut to size I wet it down with mineral spirits to inspect for any remaining glue spots. Hopefully there are none. This step also gives you an idea of what the panel will look like when finish is applied.

Of course, this being cherry, it will darken considerably with sunlight and age. Most of the darkening takes place in the first few months of exposure to strong light, but it continues for a long time. In the picture at right the wood came from two piles, one which had not been subjected to light and one which had (it was on top of the drying stack). These pieces will darken to the same color in a few weeks time.

However, you will notice some sapwood in this panel. Purists argue that you should remove all sapwood when crafting fine furniture. I respectfully disagree. I have always felt that nature does a better job of designing wood than we do. I like to expose all “imperfections” in the wood, including dark pitch pockets in cherry, or cats paw markings. I feel they add to the piece. I am sure that the Shakers didn’t throw out pieces with these imperfections, and if its good enough for the Shakers, it’s good enough for me.

A Full Scale Print Out Is Used As A Template One of the really neat features of SketchUp is that you can print drawings to scale. I printed out the headboard to full scale (1:1). It took about 23 sheets of 8 1/2” by 11” paper, though most of them were blank and I put them right back in the paper stack. I taped one side of the swan neck together and then encapsulated it with self sticking clear plastic and made a template, which I then traced on the panel. Only one side is needed for a template because the curves are mirror images and you can flip the template.

The Delta BOSS Is Used To Remove Jig Saw Machine Marks After rough cutting the swan neck curves, I used my Delta BOSS with course paper to sand away the machine marks left by the jig saw. I usually use my band saw to cut shapes like this, but a 1 1/4” re-saw blade was mounted on it and I didn’t want to take the time to change to a smaller blade. The BOSS oscillating sander does a good job, however, in the end I had to finish the job with lots of hand sanding.

This panel is rather large for the BOSS table so I used adjustable roller supports to carry most of the weight while still making it possible to easily manipulate the panel. Note that the circle in the top middle of the panel is not cut out at this point. If I would have cut it out at this point, the shaper, which will be used to shape the edges, would likely destroy the delicate points that are formed by the circle (see the first picture).

Shaping The Edge With A Large Cutter I Am Especially Alert The next task was to shape the edges. During design of the bed I chose to do this on a shaper because I could get a cutter that would form a wider shape than possible on the router. But the cutter has a rather large 5 1/2” outer diameter. Plus the shape of the swan neck is such that I had to expose most of the cutter to be able to manipulate the panel during shaping. This makes for a somewhat risky and dangerous cut. In situations like this I am always super alert, especially during the start of a cut when the shaper can grab the piece and throw it, or throw sharp pieces at you. Also, I am conscience of where my hands are at all times.

The Circle Is Cut Out With A Jig Saw Finally I cut the circle with the jig saw and repeat the BOSS and hand sanding process. When cutting pieces like this where the panel has to hang over the edge of the table, I make the cut in sections, and support the cut-off by clamping it to the panel. That way it will not unexpectedly fall an split a piece out ruining the panel. These little extra steps can save a lot of work and material and pay for themselves many times over.

The Completed Panel Ready For Finish When the panel is completed I wet it down with mineral spirits again. This time I am looking for scratches or dings. This sometimes happens due to the hard surface of the shaper and BOSS tables. If I find a mark I remove it now. If I were to skip this step the imperfection would surely show up after finish is applied and would be much more difficult to repair at that point.

This concludes Part 1 of Trundle Bed Crafting. In Part 2 I will make the swan neck frames the will encapsulate the panel. Stay tuned.


Veritas Bevel-Up Smoother PlaneMuch has been written about the relatively new bevel-up (aka low angle) planes from Veritas and Lie-Nielsen – most of it complimentary. In particular, two woodworkers I admire, Chris Schwarz and Lonnie Bird, have been outspoken about the advantages of bevel-up planes. This month’s issue of Popular Woodworking (August 2009 #177) had a great article called The Case For Bevel-Up Planes by Lonnie Bird. Anyone trying to decide between bevel-up or bevel-down should read this article. My experience with bevel-up planes, however, has been quite different. I offer the following account to present a different view.

The Lie-Nielsen Low Angle LN-164 Smooth PlaneIn December I bought my first low angle plane, a Lie-Nielsen LN-62 jack plane, largely on the strength of an article by Chris Schwarz. In March I bought a Veritas bevel-up smoother plane for a class I was to take at Lonnie Bird’s school. This was my first non-Lie-Nielsen plane and I felt like I was cheating on my wife when I purchased it. Somewhere in between I bought the Lie-Nielsen LN-164 smooth plane. In the intervening months I spent a lot of time tuning and using these babies, all along comparing them to my bevel-down Bedrock planes.

Lie-Nielsen No. 4 1/2 Bedrock Smooth Plane As an engineer by education and profession I am no stranger to design analysis. When I analyze the design of bevel-up planes I am convinced they will perform better than Bedrock designs, cost less, set up easier and are more flexible. Yet, my side by side usage and comparison over the last six months have left me wanting to stick with the Bedrock design, what Lonnie calls the “antiquated” design.

Veritas Bevel-Up Smooth Plane ComponentsSo why the disparity between what technically seems true, what the leading woodworkers say, and what my experience tells me? Part of this I believe is due to my (perhaps too long) learning curve. Perhaps I haven’t used bevel-up planes enough yet. But I am convinced that the disparity is in large measure real and physical.

Components Of The Lie-Nielsen Low Angle  LN-164 Smooth PlaneI agree with Lonnie Bird that bevel-up is the way of the future for all planes; largely because they have fewer parts, hence cheaper to manufacture and easier to tune. Both the Veritas and the Lie-Nielsen bevel-up planes have only three simple components; the body, blade and cap-iron (the Lie-Nielsen actually has four components if you count a small spacer). Compare this to the Bedrock design which has a body, frog, blade, chipbreaker and cap-iron. Also, you can buy one bevel-up plane plus two or three additional blades ground to several bevel angles and essentially have the equivalent of three or four planes.

Lie-Nielsen No. 4 1/2 Smooth Plane Components For example, Veritas offers a 25, 38 and 50 degree blade. Their planes have a 12 degree bed. Hence a resulting 37 degree low angle configuration for end grain, a 50 degree York configuration for well behaved grain and a 62 degree high angle for highly figured hardwoods. Three planes in one. In the Bedrock design you have to purchase multiple frogs to achieve this. Even then it is difficult to get a 62 degree cutting angle, which appears optimal for highly figured woods.

Sharpening A Lie-Nielsen Bevel-Up Blade Requires A Jig Like The Veritas To Maintain A Right Angle All of that is true yet, call it feel, call it human engineering, call it whatever you want, but bevel-up designs are at least two generations away from getting it right in my opinion. While the Bedrock design has more parts and is more difficult to tune, like many woodworkers I have a number of planes tuned for specific purposes. This means I tune them once and avoid reconfiguring them so that I don’t have to tune them again for quite some time. What’s left after tune up is minor blade depth and lateral adjustments – and that is where the Bedrock design excels. The human engineering of the Bedrock design is such that you can make either a blade depth change or a lateral adjustment between strokes while returning the plane to the starting point of a pass. Both adjustments are right there at your finger tips. No hunting required, no need to turn the plane over or change hand position to make an adjustment. Also, both adjustments are silky smooth on the Lie-Nielsen Bedrock designs, and both are like vernier adjustments that give precise results.

Lie-Nielsen bedrock Tote (Front) & Veritas Bevel-Up Tote - Note Difference In Angles Contrast this to the Veritas and Lie-Nielsen bevel-up planes. The Veritas seems to be the most clumsy of the two manufacturers. The adjustment mechanism for both depth and lateral adjustment is a knob that is placed too low for the thumb or index finger to access without moving your hand from the handle. You can see this in the picture at right. Further, I find that if I tighten the lever cap to a degree required to keep the blade from shifting on its own the lateral adjustment is too tight to operate smoothly.

Lie-Nielsen Bedrock Tote (Front) & Lie-Nielsen Low Angle Tote - Note Difference In Angles The Lie-Nielsen low angle design doesn’t require a lateral adjustment relying instead on a tighter machining of the bed alignment to the edges of the blade. However this requires that the blade be ground and honed precisely at 90 degrees to the edges, a task that is easily performed, ironically, with the aid of a Veritas honing jig. The Lie-Nielson’s depth adjustment seems slightly better human engineered than the Veritas. Neither come close to the ease, smoothness and controllability of the Bedrock.

One of the features of the bevel-up design that is far superior to the Bedrock is mouth adjustment. Both the Veritas and the Lie-Nielsen planes make this easy. Simply loosen the front knobs, adjust the mouth and retighten. In the Bedrock design you have to move the frog position requiring the involvement of three screws. It is quite difficult. However, like I said, in practice this adjustment is rarely required if you dedicate your planes for specific configurations.

The Lie-Nielsen No. 4 Bronze Bedrock Smooth PlaneTuning a Bedrock is second nature to me since I have been doing it for so long. I can achieve wispy thin and wide shaving with very little effort. For some reason I can’t explain other than a learning curve, I can’t achieve a tuned state nearly as quickly with the bevel-up planes. This is puzzling to me but I can only hope it is not a permanent condition.

The last part of this comparison is a somewhat nebulous factor, let’s call it feel. The Bedrock feels right in my hand. It’s beefy (those extra components have a benefit), the grips (tote and knob) are just right and everything is in reach without moving my hand from the grip. I can easily get in a zone and plane away effortlessly even with the 55 degree middle pitch.

Mouth Adjustment Is Easy On A Bevel-Up PlaneThe bevel-up planes, on the other hand, seem too light; my hand and arm extension seems wrong; I find myself fighting the lower angle which is tiring. Look at the two pictures above comparing the totes of the Bedrock design versus the totes of the bevel-up planes. Notice that both Lie-Nielsen and Veritas bevel-up planes have a lower angle tote forcing your bodies forearm and shoulder lower. I suspect the designer’s rationale was that for steep pitch configurations you need to be pushing more behind the plane to compensate for the increased force required. That makes sense, but it’s unnatural; and you have to pay this price even for mid and shallow pitch configurations, which are the pitch configurations most often used in the shop.

Lastly, in this nebulous category called feel, the bevel-up controls require me to break my planing stride. I usually approach a smoothing task, especially for figured woods, with the blade slightly retracted. On each pass I extend the blade ever so slightly until I am taking that wispy thin cut I want. During this time I also make lateral adjustments. With the Bedrock I do this on the fly. I can’t do this with the bevel-up planes. It’s stop and go with each adjustment

Maybe I am just too biased to allow for a new feel, I don’t know. But I have been at this comparison for nearly six months and still haven’t achieved the advantages my engineering analysis, and the woodworkers I admire and aspire to be, say I should. So for now I’ll stick with my Bedrocks thank you.


Powermatic PM1900 3 HP 1 Micron Canister Dust CollectorThere have been a few recent additions to my shop. My old dust collector was a 3 HP Reliant which I had for about eight years. It was the bag type, both top and bottom. I wanted a 1 micron filter canister. Since Reliant is out of business I tried retrofitting a Delta canister. The diameters were slightly different so I used single sided tape foam and a spring clamp steel belt to mate them. It worked for a few years, but then the canister began blowing off when the bags were nearly full. After filling my shop with saw dust on several occasions I decided it was time to buy a new Powermatic PM1900 3 HP unit. Now I suppose I can’t stall any longer. It’s time to finally pipe my shop for dust collection.

Note the nice Powermatic sign that came “free” with the unit. That alone made the purchase worth it.

Peachtree Supreme Drill Press TableI was at a Woodworking Show in Marlboro MA this past winter and saw a drill press table that impressed me. I don’t think there was anything I couldn’t do on my drill press before purchasing a table, but it sure seemed like it would make things easier and quicker. So I purchased a Peachtree Supreme table. This table is thick and sturdy. It came with the T-tracks installed and very little in the way of assembly required. I have already found applications that are much easier and more accurate than my old methods. I think I am really going to like this addition.

Trying Out The Veritas Bevel Up Smooth PlaneI have a nice collection of Lie-Nielsen planes. Though I am not a collector, I am a user. I don’t buy a plane unless I intend to use it. Recently I was scheduled to take a woodworking course. The school sent me a list of tools required for the course, most of which I have. I have Lie-Nielsen No. 4 and 4 1/2 smooth planes with 50 & 55 degree high angle frogs. But the school was quite insistent that the smooth plane be Veritas Bevel Up.

So, while at the same show in Marlboro I visited the Lee Valley booth and asked for a demonstration. I was escorted to a bench where a visitor was already trying the bevel up smooth plane and having difficulty using it. I mentally noted that I though he didn’t know how to use a plane. When it came my turn I had the same difficulty and felt somewhat embarrassed. I asked the Lee Valley sales guy to demonstrate the plane. He had the same problem and spent twenty minutes trying to adjust the plane but to no avail. I walked away wondering if I should buy this plane and decided to think on it long and hard.

Veritas Bevel Up Smooth Plane Produces Thin Wide ShavingsBack home I read a number of reviews and articles on the Veritas plane in question. They were quite glowing. A few months later I purchased one. I must admit, I felt like I was cheating on my wife adding a Veritas to my Lie-Nielsen harem.

When the Veritas came I was anxious to try it out. My first impressions of the packaging and fit-and-finish are that this plane is not the same quality level as the Lie-Nielsen. I plugged on. The set up was quite different. It took me some time to complete. The depth adjustment screw struck me as a little flimsy and depth adjustment too course. After completing the setup I gave it a try with no honing of the blade. I was surprised at the smoothness of use, the wide thin shavings I was able to cut, and this with no honing. The more I used this plane the more I liked it. But it still didn’t feel as comfortable in my hands as the Lie-Nielsen smoothers; nor as sturdy and as well finished.I Need To Know - Veritas Or Lie-Nielsen For Smoothing Figured Woods

My curiosity has been piqued. I intend to buy a Lie-Nielsen low angle smoother to give these two manufacturers an apples-to-apples test. I need to know which of these babies will produce the best finish on figured woods. I’ll try them both, straight out of the package with no honing. Then I will hone them and work them some more. Tiger maple should expose a winner. Does that sound like reason enough to buy another plane? I hope so.

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