The Drop Leaf Table Addition: The Incremental Cost of Design Complexity

This entry builds on a previous one where I described a part design paradigm based on complexity where every new feature added to a single part required more caution than the last, because once a part began to acquire more features along with the time and effort required to produce those features, the part itself began to incrementally increase in value. A mistake with each additional new feature machined would therefore prove increasingly more costly than the operation itself to complete that feature, as the number of features were added to a part to complete it.

I found myself trapped in that same concept as I routed the final half-inch quarter-round profile on the two opposite edges of this table top. Each part that makes up the top assembly is fairly simple in and of itself not counting the walnut panel quadrants with their computer numerically control routed circles, but the assembly of those parts was done in stages that included a complex cope and stick edging process between the center panel and its two opposing front and back edges. Routing the small dado that ran along both side edges underneath the top was difficult enough until I had to begin the last process.

The last process in completing the top was to route the large quarter-round profile on the two side edges without the router bit blowing out the ends. I really had no choice therefore but to use a hand-held router instead of the router table, and because of the larger router bit, I had to use a plunge router instead of one of the smaller, more easily controlled hand-held fixed-base routers I own.

No single one-pass, large removal of stock occurred as I routed the quarter-round profile. It was light passes all the way, taking off only a little at a time to insure a clean, smooth, issue-free profile using a tool not exactly well know for its finesse. A mistake here could have cost the whole top. I obviously pulled it off, but if I had not, that incremental cost concept would have come around to hit me hard. Very hard.

Like the saying goes, just because you can doesn't always mean that you should. Although in the end, risk paid off in the final result.

The Glue Strength Test: How It Informs Design

I began a simple project in the workshop that will wrap up soon to test the new cyanoacrylate glue that recently came on the market especially formulated for woodworking applications. This project is a simple tapered leg table with tenoned apron sections glued into mortises that are routed into the legs. The fast set time of the cyanoacrylate glue would greatly facilitate the assembly of the legset.

Recall that I conducted a strength test of the glue with the help of the engineering department here at the University of Minnesota before I began building the tapered leg table as described in a set of earlier posts that are listed below. The glue strength test indicated that the new cyanoacrylate glue did not bond as well as traditional woodworking glues, and for that reason I decided to assemble the legset using a traditional glue even though I think that the strength of the joinery used here would not have been an issue. I like to be sure about these things though when it comes to my work.

http://stevepanizza.blogspot.com/2013/11/the-glue-strength-test-results.html

http://stevepanizza.blogspot.com/2013/11/the-glue-strength-test-engineering-test.html

http://stevepanizza.blogspot.com/2013/11/the-glue-strength-test-introduction.html

The process of gluing and clamping the legset was done in two stages, and each stage took a full day of clamping. Using the cyanoacrylate glue would have meant that the glue-up phase of the legset could have been completed in only one day as quick dry time is its primary advantage. The benefit of strength won out over completion rate though.

Another way to look at the glue strength test results though as they relate to this project design is that I could have increased the size of the apron part tenons to increase the glue surface area if completion time had absolutely been an issue here as more glue surface area increases joint strength. It may help to know in the future that I have this option during the design stage of any project.

I think that uses for the new cyanoacrylate glue will eventually develop where its short drying time can be used to advantage in situations where strength is less important. So for now it stays in the shop as another tool to use when appropriate.

The Glue Strength Test: Results

We conducted the glue strength test today using a new set of test articles designed to fail well under the maximum load capable of being applied by a tensile strength test machine here at the University of Minnesota. My cohorts in this project were undergraduate engineering student Aaron Bardon, and Professor Jeffrey Schott of the Chemical Engineering and Materials Science Department at the University. I said in my previous entry that my assumptions and calculations were simplified, and that part failure would probably be based on a number of modes of failure rather than on one simple cause. The results were surprising to us to say the least.

The results are summarized here. I should state up front that no particular glue or brand is advocated or disparaged here. Different varieties of glue bring their own unique characteristics to a project, and this test is simply one of strength comparison when applied to a set of identical parts constructed of quartersawn red oak with mortise and tenon joinery.

The three varieties of cyanoacrylate glues will be discussed first since this project was designed to test a new brand of these glues specifically formulated for commercial woodworking applications against the traditional water-based polyvinyl acetate wood glues. These are marked four through six in the photo here, and their test results are summarized below.

4. Cyanoacrylate glue with short open or working time. The glue failed at around 2000N or about 450 lbs. of force in tension.

5.  Cyanoacrylate glue with medium open or working time. The glue failed at around 2400N or about 540 lbs. of force in tension.

6. Cyanoacrylate glue with long open or working time. The glue failed at around 1800N or about 405 lbs. of force in tension.

The important thing observed here is that all three varieties of cyanoacrylate glue failed rather cleanly when a force similar in magnitude was applied, and failed before the wood did. I predicted that the wood would fail in shear first, not the glue. This was not the case though.

Two common water-based polyvinyl acetate glue formulations are marked one and two respectively in the accompanying photo here. Test results are summarized below.

1. PVA Type-I woodworking glue. This part did not fail even at the maximum test force of 5000N or 1124 lbs. applied in tension.

2. PVA Type-III woodworking glue. The part containing the mortise itself failed parallel to the grain of the wood approximately at the mortise depth. The section containing the mating tenon remained intact. The glue joint did not fail. The wood failed either in tension or shear perpendicular to an applied force of 3900N or 877 lbs. A stress concentration at the mortise probably contributed to failure here.

I included two special case parts for comparison, and their test results are described below.

3. Polyurethane glue. The glue failed at around 2000N or about 450 lbs. not too unlike the three cyanoacrylate glues. I included this glue in the test because it is specifically promoted for its high strength. In this test though, not so much.

We concluded the test with the part marked #20, and any woodworker knows what's coming. The part was joined using a #20 biscuit glued with PVA Type-I woodworking glue. What most woodworkers would not expect is that the part shown in the photo did not fail when tested to 5000N or 1124 lbs. I now have a much healthier respect for biscuit joinery, and would consider using a biscuit or two for strength rather than simply for alignment as is usually the case in my shop.

The cyanoacrylate glues however, do not get that same respect. They might have been useful to me in the construction of an organ case, but case frame members have to carry heavy loads, and these glues appear to be significantly inferior to the polyvinyl acetate glues with respect to strength. Although all joint tolerances were kept close, the water-based polyvinyl acetate glues may in the end have superior bonding strength because they are capable of swelling the joint. Because they do not cure within minutes, the polyvinyl acetates may also penetrate the wood pores deeper resulting in a better and stronger bond.

We debated these ideas as we concluded the test, and to be honest, this is where the fun in all this is. You make a guess about something and test it. Sometimes you get it right, but sometimes the test can lead you in a completely new direction. I learned a lot today.

Much thanks goes to Professor Jeffrey Schott and Aaron Bardon at the University of Minnesota for graciously agreeing to be part of this test project.

Bibliography.

Higdon, A., Ohlsen, E., Stiles, W., Weese, J., & Riley, W. (1976). Mechanics of Materials. New York: John Wiley & Sons.

Hoadley, R. Bruce. (2000). Understanding Wood. Newtown: The Taunton Press.

The Glue Strength Test: Engineering Test Articles

I introduced the glue strength test project in my previous entry. Working with an engineering professor and undergraduate student at the University of Minnesota, the project is designed to test a new woodworking glue against traditional glues by tensile strength testing a series of identical mortise and tenon joints to failure. The problem with the initial test was that the part was built too strong for the test machine which could not exert enough force to cause it to fail.

I decided then to apply engineering to the design of a new part that would hopefully experience failure, and therefore provide a meaningful test of one glue against the other. I had to make assumptions about where failure would occur to model the modes of failure most likely to occur, and decided that the glue could fail where the mortise and tenon were joined, the wood itself could fail at the tenon due to the force in tension being applied by the test machine, or the wood could fail at the tenon due to the shear force applied by the test machine.

I began by looking up the equations and published strength data for both the glue and wood used in the test samples pertaining to the three modes of failure I identified as possible. What I found was that there was little published data on the strength property of wood in tension parallel to the grain as this number was always much greater than other strength property figures for other modes of failure of wood in general. The more likely modes of failure then were going to either be failure of the glue, or failure of the tenon in shear.

I set up the document shown here in the iPad app PocketCAS pro to calculate the force at which a joint would fail due to both glue failure, and failure of the wood due to shear force. My goal was to design a joint that would comfortably fail within the test machine force limit of 5000N or 1124 lbs. There is an axiom among woodworkers that glue is stronger than wood, and the equations prove this true. The wood will fail in shear before the glue will fail according to the math, and I designed the tenon dimensions to comfortably fail well under the maximum force the test machine is capable of exerting on the part assembly.

An interesting find obtained by the mathematical model is that such a small tenon can withstand a force up to 667.5 lbs. due to the shear strength of red oak parallel to the grain. I expect this number could be different by some because there may not be a single and simple mode of failure, but rather failure may be multi-modal. In other words, the glue that joins mortise to tenon may play a role in how the joint fails.

I sort of hope this is the case because that would mean that the strength properties of different glue types factor in, and are somewhat represented in the test result data obtained. If so, their effect on joint strength will factor into my work. If not, there is no strength restriction placed on the type of glue I can use in any one construction.

A last word about my assumptions and corresponding calculations. They are simple, and do not represent anything near the complex mathematical models that may more accurately describe the behavior of the glued mortise and tenon joint under tension. I am at this point looking for a ball-park figure so that we can get one of the assemblies to fail during test. An analysis of test results will later provide a more accurate direction to take with regard to the interactions between force, glue, and wood in this type of joint.

The Glue Strength Test: Introduction

I recently came across an article in a trade journal about a company that had begun producing a new glue for commercial woodworking applications that promised quick dry time thereby negating the lengthy times normally associated with clamping glued parts. The new glue is a cyanoacrylate glue, and is far different from the traditional polyvinyl acetate woodworking glue I normally use. Consumer formulations of cyanoacrylate glue are commonly referred to as super glue, or simply as CA glue.

The quick dry time got me interested though because there are applications where this could be useful if the glue proved to be strong enough. I contacted the company making the new glue for more information, and they provided me with a sample pack of the three varieties they offer differing only in the open or working time of the glue, short, medium, and long.

I also happened to recently meet engineering student Aaron Barden who specializes in materials science at the University of Minnesota. Materials Science at the University is part of the Department of Chemical Engineering. Aaron put me in touch with Professor Jeffrey Schott who agreed to be part of a tensile strength test using the new glue against the traditional glue in parts joined from each.

I decided to make six t-shaped parts using mortise and tenon joinery for the test such that two were glued with commonly used polyvinyl acetate glues, one with polyurethane glue, and the remainder with the three varieties of the new cyanoacrylate glue. I chose a tenon size that seemed typical for a normal frame design. With six test articles built, we set about to test the strength of the glue joints.

Testing was done on the tensile test machine shown above. A part is clamped in the machine which applies a force that increases steadily over time, and because most materials stretch some when a force in tension is applied, the machine plots that force against the change in length of the part until ultimate failure occurs. We didn't expect the wood to stretch much over the course of the test, but we did expect the joint to fail before the maximum force limit of the machine was reached. The joint astonishingly did not fail under the maximum force applied to it of 5000 Newtons, or about 1124 pounds. We agreed to run the test again with new parts designed with smaller joints that would actually fail.

So walking back after that initial test conducted during the lunch hour, I concluded that I needed to understand the shear strengths of both wood and glue involved, and make an attempt to apply some real engineering to the problem. There are some surprising numerical results for the size of a joint that should fail under the load parameters capable of being produced by the test machine, and I will publish those in my next entry.

The next step is to produce new parts based on the numerical results obtained from published data on the shear strength of both glue and wood, and then test those parts to catastrophic failure. In doing so I can get an idea of the relative strength of the new glue, and be comfortable using it as a substitute method where appropriate.

Tonal Design Then and Now

I wrote in a previous post about the first pipe organ I built where I combined old organ pipes with new. The art and science of creating a certain sound from a pipe organ is referred to as tonal design, and it can really be both art and science. Building that first organ was in a way almost easier than building a clean-sheet design because I had a place to start and a place to finish. The organ that I am building now has neither a place to start nor finish, and I'm not sure which direction I want the design to take yet.

The old pipes that were made available to me provided the first organ I built with a place to start. Their dimensions determined to a large extent the dimensions of the additional pipes that I added to determine the overall core sound of the organ. This core sound is referred to by German builders as the plenum. The term most often used for the organ plenum in this country is chorus. Those same German builders refer to how well the pipes combine to form a unique sound as the unity of the plenum tone.

There are different ways to accomplish the tonal design of an organ plenum by selecting proper pipe dimensions - or pipe scales - of each set of pipes that form that plenum. Some methods rely on experience and subjectivity. Some are purely mathematical, and base the production of sound coming from an organ pipe on energy principles and fluid dynamics. I decided not to pursue that direction even though my engineering degree would have served it well. My background in music led me to rely more on art than science when designing the tonal result of a pipe organ.

The design of my first pipe organ as an independent builder had a starting point in the old sets of pipes I used in its construction. It also had a place to finish. The instrument would end up in a particular church building that had certain acoustic properties. The acoustic properties of that building also determined dimensions for the new pipe sets I added to complete the idea of a plenum within the tonal design of that organ. I had to make sure though that new and old organ pipes not specifically intended to be used for solo sounds be carefully unified. The old masters knew well how to do this.

I used a graphing method to represent the relationship of an individual organ pipe scale to a reference scale, and by plotting all pipe scales of the organ on the same graph in reference to that standard reference, I could predict how those pipe scales combined to form a plenum tone. The graph shown here is the combined scale graph of the first organ. Its plenum tone turned out well. This I can demonstrate here by the recording of a Christmas carol made on this instrument with its plenum or chorus stops drawn.

Something interesting the graph shows is that the data curves for what are considered the principal pipes - or those that make up the core sound of the plenum - are not straight lines but are concave. These are the curves for the Octav 2' and Quint 1 1/3'. This particular scale chart trend is evident in Baroque organs built in southern Europe, especially southern Germany, France and Italy, where builders used scaling practices that produced a particular tone color providing something just enough different and special to me.

As I consider building another organ now, I need to determine what its plenum sound will be without having a predetermined place to start, or without knowing where it will ultimately go. I do know however how to design a unified plenum, and how important this is to the ultimate success of the instrument.

One final thought. This post is not intended to be anything close to a comprehensive discussion of pipe organ scaling practices or tonal design, and a good builder or student of the pipe organ will realize this. There is much more involved than what is presented here. This post is a simple discussion of a method I used to create a tonal design, where certain conditions provided some initial direction to that design, so that someone reading this post can gain an appreciation of the process I will go through to create one more new tonal design.

There are many other methods used to achieve a tonal result, and one thing that I was taught is that no one method is correct or incorrect if used properly to obtain a good outcome. Each new organ built is an expression of the artistry of its builder. I simply use what works best for me.

Translating Experience

I seem to often translate experience from one familiar field to another. My recent experience with this in the last few weeks was in assembling a new jointer and table saw.

A few years ago when the economy took its downturn, I built a few bicycles in the workshop mainly to keep myself productively occupied with something else other than woodworking. It was a great opportunity to transfer mechanical skill to bicycle building, and it was something new to me. I spent a lot of time learning about new parts, their names, what they did, and the special tools required to mount and adjust them on a bicycle frame. I developed skills needed to get everything mounted, aligned, and adjusted correctly.

The assembly and alignment of woodworking equipment had never been something that I took as seriously as bicycle assembly. I think a lot of woodworkers are like this because our skill set is woodworking and not necessarily the mechanical aspects of machinery. We are also more interested in putting a new machine to use than we are in its assembly.

I had thought that the brief time I spent building bicycles left me with a healthy hobby, but not much beyond that until I started to assemble the new jointer and table saw where I began to notice how uncharacteristically meticulous I was about each stage of their respective assembly. That does not mean that my work is now better for it, but it does mean that I have a better understanding of what a machine can bring to the process of building by better understanding how it achieves accuracy and operation.

#hashtagging #design

I plan to build an organ again. It will be different from what I built in the past because it would not need to be built for the requirements of church use. It will be a small instrument built to accompany one or a few voices, or maybe another solo instrument.

But just what this organ would look like I was not quite sure. Many approaches came to mind as I began to think of different ways to build the organ, but none of those were starting to focus on any one single design.

There is an interesting tool now used by most social networking sites, the hashtag. A hashtag is a word or short sequence of connected words preceded by a pound sign as in #hashtag. A hashtag is used as a searchable keyword on a topic, and because of that, they are really nothing more than short descriptors regarding something that someone has posted on a particular site. I thought what if I were to hashtag this organ design, and wrote out some of the attributes I thought it would have. Here is the list.

#shortcompass
#narrowscaled
#lowwindpressure
#accompanimental
#historicallyreferenced

I recognized this list as belonging to the first organ I wanted to independently build when I first opened my original workshop, and before I built three organs from that workshop for church use. A lot of that original organ design still exists in the form of archived computer files, and the screen capture above shows what I thought the design would originally look like.

The short exercise in hashtagging directed me back to a concept. One worth building again.

Summer Changes

I decided a few weeks ago to upgrade the primary set of power tools in my workshop. By primary set I mean those that are used to do the initial heavy lifting, the table saw and jointer. You could include the planer in that set of machine tools also. I focused on upgrading the table saw and jointer though, by ordering new tools from Grizzly after doing a lot of research beforehand.

My organ building workshop was mostly populated with stationary power tools from Grizzly, and I like the fact that the new tools again came from Grizzly Industrial. The new table saw and jointer arrived this past Friday, and it was quite an interesting chore to move multiple shipping crates from the loading dock down to my workshop even with much appreciated help. I will be in the process the next few weeks of doing all the assembly and set up work to render them operational.

Thanks to John Doric and his girlfriend Laura for some much needed help with some of the heavy lifting last Friday night. I think we all admit that Laura - replaced in the photo here by a surrogate engine hoist - did most of the work.

How to Design Organ Case Pipes

This post is about my use of design technology that assisted me in building several mechanical action pipe organs as an independent pipe organ builder. I am going to use the original design objects that I used to build the organ described in my previous post here as examples. That organ was designed as a new instrument built around a core set of late nineteenth century artifacts. The challenge lay in creating a valid functional design built around those artifacts that were specifically three sets of discarded organ pipes still valuable for their great tonal beauty.

An interesting aspect of that pipe organ, and all subsequent that I built, was the use of technology to help successfully achieve the final results. It must be apparent from my previous posts that I have a strong background in computer aided design and manufacturing technologies.

I wrote several computer programs for pipe organ design shortly before I began building pipe organs as an independent builder. The programs automated and simplified tasks that were particularly challenging by creating useful geometry in a computer aided design and drafting program.

Pipe groupings that make up the front of an organ case are a traditional part of early organ building, and one of the tasks I simplified by using a purpose written computer program was to accurately model the front pipes that would form part of the organ case design. The front case pipe grouping for an organ I built is represented here in both its computer form, and in a photo of the actual instrument.

The image at the top of this post is a screen capture of an organ case pipe design program I wrote using a Java development tool called BlueJ. I used BlueJ to program in Java while briefly working at a small private liberal arts college that followed my stint as an organ builder, and I found myself in a position there to learn an object oriented computer programming language. The original organ case design program was written in a procedural programming language, and I used the opportunity to rewrite one of my organ design programs in a new programming language paradigm to significantly lessen the learning curve.

The organ case pipe design program like the other programs I wrote created a script file of drawing commands that produced accurate geometry when read into a computer aided design program. The result of the case pipe design program was a set of twenty-five accurately dimensioned pipes interpolated from three user input octave dimensions that determined the scale of the set. The interpolated values were accurately computed using geometric progressions.

The pipe geometry created in the computer aided design program could then be used and edited to create a set of pipe groupings visually appropriate to the intended organ case design. I hope the screen images included here adequately demonstrate this process without going into any further discussion that would be well outside the scope of this post.

Windchest design with nested pipes in plan or top view represented another major design challenge that I simplified by writing a set of rule-based winchest design and pipe nesting programs. A screen shot of the windchest design in plan view for the first organ I built is shown below. The rectangles represent the plan view outlines of the wood organ pipes, and the outer circles represent the plan view outlines of the metal organ pipes. The inner circles represent special devices called slider seals. An associated computer program would calculate the appropriately sized slider seal based on the wind requirement of its corresponding pipe, and represent it in the drawing as a uniquely colored circle.

Reuse and Repurpose

My workshop is located in a building peripherally considered to be part of the Northeast Minneapolis Arts Association. Each spring the association hosts an open studio art tour know as Art-A-Whirl where the largest concentration of activity can usually be found at the Northrup King Building. It struck me when walking through the Northrup King Building not long ago how many artists reuse old material in their new work, and because of this I thought about the first organ I built as an independent pipe organ builder.

That organ came about when I was asked if I would be interested in the remains of an early twentieth-century pipe organ that were removed from a church in northern Illinois. What I found useful in that material were three sets of pipes that could be used to make a late-baroque cabinet organ if revoiced and added to by new pipe ranks that would provide the new organ with a complete and well-rounded set of tonal resources.

I therefore set about designing a one-manual mechanical action organ built around a specification that included the three older sets of pipes along with two new sets that completed a unified tonal plenum based on the late baroque style common to southern German organ building of that period. The new organ design included a new slider windchest, new wind supply, new casework of solid walnut, and a new mechanical action to directly connect each key to its corresponding pipe valve, all produced in my shop.

I contracted out the keyboard and metal pipes to respective firms who did work in reproducing early organ material to stay true to the historical nature of the instrument. Carvings were done by a local artisan whose normal business was furniture refinishing.

I would not have originally intended to build an organ using older material had it not been available for free, although organs have been built this way for centuries. Obviously though, there are many artisans who use older artifacts in their work, and base much of it on this principle of reuse and repurpose.

The Alice Table: An Example of Fluid Design

 There have been two simple projects described in earlier posts that experienced evolution as their production progressed. I can barely recall a single project where this has not occurred to some degree, and as a matter of fact, I feel that it is the nature of design itself as guided by the creative process that forces fluid change on a project as it evolves from design to actual outcome.

The Alice Table was no exception as the design of the top changed during the course of the project. The top was originally to have edges trimmed with mitered corners. After the base of the table was completed, it started becoming clear that a top with mitered trim would not look right against the four very linear frames that made up the base. I decided therefore to make the top as a sort of frame and panel construction to compliment the basic frame construction of the base. I even ran a cope and stick profile along the entire front and back edges of the central laminated panel to join the mating front and back rails.

The cope and stick technique produced an interesting design element in that it produced a visually appealing exposed joinery detail at the front and back of the side edges of the table top. I had a decision to make at this point, and decided to go ahead and route a quarter round profile around the table top edge. This was done as a period detail to highlight the exposed cope and stick frame joinery, and then mirrored on the inner cross frame shelf to maintain the table within a table design concept.

The table had not taken on any specific design statement until this point, but now it appeared that my former work in producing historically inspired design helped to move the table in that direction. Going back to a time when I practiced woodworking as a profession through musical instrument building, the inclusion of a certain period element produced a design with historical inspiration. My dad used to say that water always flowed to seek its own level. I guess that proved true with the final outcome here.

The design elements as they evolved of basic frame, frame and panel, and profile detail combined to produce a visually integrated whole. I was fortunate in this project to have a client that understood and appreciated the creative process and its application. A better table resulted.

Update: The client posted this to her Facebook page.

THANK YOU EVERYONE WHO HELPED ME CELEBRATE A SIGNIFICANT BIRTHDAY LAST WEEK. THE CARDS, CALLS, EMAILS AND EVENTS JUST CAME COMING. THE HIGHLIGHT WAS THE DELIVERY OF "THE ALICE TABLE" THANK YOU, STEVE. I ENJOY IT MORE AND MORE EVERYDAY. BLESSINGS TO ALL OF YOU.
LOVE, ALICE

There's no better feeling than a good endorsement from a client after completing a project.

The Problem with Sales in a Difficult Economy

I opened a workshop here in Minnesota to produce work that would sell on consignment in local galleries, and doing it this way would allow me to design and build whatever I wanted. This was a model that worked in the past. The recession hit though, and gallery sales slowed way down and still have not recovered. One of the consignment galleries in fact closed this year.

So rather than stay with a model of design-build-sell that currently does not work, I have focused more time during the past few years on workshop and methods development rather than actual output, and some of that work is detailed here. For example, both the light fixture and candle holder projects taught me technique that I applied to the Alice Table commission just about to be completed.

The idea to build the candle holders came from a short pile of imported scrap wood that I had no use for, but felt that such beautiful wood should not end up thrown away. I built ten, and brought five to a retail gallery, but again there they sit proving that not even product mix is the answer.

I was recently asked though to donate something to a benefit auction held on the University campus. Normally this would not have been realistic, but wouldn't you know that I had five small objects sitting in a cabinet back at the workshop that were readily available to use in a perfect sort of marketing experiment. Therefore from the five candle holders remaining at the shop, I decided to donate one small and one large candle holder, being really interested in what value they bring at auction relative to their value appraised by staff at the gallery where the other five reside.

The auction is coming up next week, and its result may give me some useful information back. If not no harm, no foul. If I learn something useful though, I'll provide it in an update.

The Alice Table: Managing Visual Complexity

I completed the woodworking portion of the Alice Table two days ago, and posted a photo of the yet to be finished project. Someone pointed out to me that the table is really a table within a table. That person is correct. The two cross frames support an inner shelf, and that inner structure can be seen as a small table by itself.

The base of the table is made up of two side frames joined together by the two inner cross frames. The two inner frames fill space that would otherwise be empty in many other table designs, and often it is good to have empty or sufficient white space in a design. The inside cross frames though create a certain amount of visual complexity in addition to their practical function as simple structures that physically join the side frame assemblies together as well as support an inner shelf.

Yet the table appears unified because of repetition. Side and cross frames share the same fundamental architecture. The only difference besides being sized differently is in linear movement. The side frames extend from front to back while the cross frames extend from side to side. I designed each of the surfaces they support to convey that same linear movement through grain direction. The grain direction of the inner shelf runs its length from side to side to emphasize the same visual direction taken by the supporting cross frames. The grain direction of the teak panels and joining walnut rails of the table top runs from front to back to accomplish the same visual effect for the supporting side frames.

You might think that there could be tension created by using wood grain in this way. Similarly the two cross frames that fill the inner space could have contributed to a feeling of clutter. Not at all though. The design appears unified and well-proportioned, and does so because of effective use of repetition and linear movement. The table appears simple and foundational despite its relatively complex architecture.

Developing Ideas in the Internet Age

A blog entry appeared in a major woodworking journal recently with regard to a change that has come about concerning the development of ideas, especially with new forms of social interaction brought about by Internet-based social networking. I actually wrote a comment.

The entry can be found here.

http://blog.woodshopnews.com/tbaw/?p=744

The writer's viewpoint is generally in favor of what is now normally referred to as crowdsourcing, where ideas are solicited from a group of people. This is obviously now much easier within Internet groups using Twitter, Facebook, or an online forum for example, and is a concept that has grown in popularity. Read any history about major inventions though, and one gets the idea that sharing ideas so freely wasn't always popular. Most famous inventors were at one time or another involved in a patent lawsuit against a competitor. In fact, patents are specifically awarded to protect someone who intends to materially profit from his or her own unique idea.

So now if someone crowdsources an idea though, then because ownership of that idea no longer belongs to any one individual, I suppose that any profit from that idea would have to come from the implementation of that idea through manufacture. Most practicing artisans I know are both proud and protective of the ideas that give their work its own identity. Ideas are intellectual property, so to me the idea of crowdsourcing may not apply to all people in all situations.

Industrial-Retro-Indie-Hipster-Techno Research-Based Woodworking

All of the words used in the title of this entry have been used at one point or another to describe whether in complete or partial truth the design statement my current work is making. There are projects that actually pay the bills, and then because the economy has slowed down that activity, there are projects that are producing a body of knowledge or at least are adding to it.

There are aspects to a project I have coming up that I need to understand more completely before actually committing resources toward building it, so I decided to create a series of simple objects to prototype those aspects and their associated construction methods. The original purpose of this prototype set involved the design use of tungsten filament light bulbs, but as the project evolved so too did the objects used to hold the bulbs.

Those objects are the end result of an evolutionary process as there were several iterations of each that came before I arrived at the final set you see here. Each design iteration had fewer parts as time went on, but those parts became increasingly complex to build as I described in an earlier entry. The most significant development I think that came from this project was in the direct use of design model geometry to graphically generate computer numerically controlled tool paths. An artisan studio or workshop is a high-mix, low-volume build environment, and being able to adapt methods quickly to different design requirements to achieve acceptable build time becomes more important if a business case is involved.

A good reference source for some of the underlying principles that I currently attempt to address through prototyping design work can be found at the website for the University of Wisconsin-Madison Center for Quick Response Manufacturing.

The Incremental Cost of Part Complexity

I was introduced to parametric solids modeling about the time I completed building the pipe organ for Zion Lutheran. The leading program at that time was and still is SolidWorks. Although I wanted to use solids modeling then, I continued to use 2D computer drafting because of the high cost of 3D design programs including SolidWorks.

A few years ago, the cost of a reasonably well featured solids modeling program became low enough that I could justify incorporating it into my design work. Now I finally had a real engineering design program to use. The first thing I immediately noticed was a reduction in errors in the workshop. A good solids design requires that one accurately model each part and assembly, and having those represented in drawing format let me clearly see each part feature, and the relationship of each part to its parent assembly, in three dimensions. All of that helped me to build better in the workshop.

But something else happened that I did not count on. The parts I designed started becoming more complex. Parts began containing more features as parts started taking on more function within an assembly while the assemblies themselves began to have less parts overall. Look at the exploded view of the assembly above as an example. The assembly itself has only four parts. That seems simple enough. But look at the notched rail. That part is designed to hold a component mounted through the hole located along its top. The notches themselves locate the assembly along rails that are part of a larger assembly. And the two vertical slot mortises receive the tenons of two tenoned cross members that hold it all together.

Each of these features, the notches, hole, and mortises, must be accurately and sequentially machined until that one part is completed. The interesting thing I find now is that the cost of producing each feature is not simply the time it takes to machine that feature, but the additive cost of producing each preceding feature if a mistake is made while producing that feature. This is a problem because anyone who has done any woodworking knows that the activity is inherently error prone. A mistake at the end means having to go back and do a lot of work all over again, all the blade changes, tool setups, sizing, etc., and all for one part.

The projects that I've journaled here reflect an iterative change in part design and part to assembly relationship for me. All seem deceptively simple enough, but all are providing me with valuable experience in designing and building within a new paradigm. I've known others who have built in this style of complex efficiency and part economy especially among the German pipe organ builders. I find it an interesting and intelligent way to build.

The Alice Table: An Introduction

I recently received a commission to build a small side table for a client. Obviously that client's name is Alice. She asked me to build a table for her using teak so that it would match her current set of furniture. I suggested using walnut along with teak to keep cost reasonable. I often use more than one type of wood in my work to provide variation in color which should be obvious by now.

Alice has a degree in art education, and I kept this in mind as I did the design work making sure to use color and space well in an otherwise functional object. We went through a number of design iterations together by email before deciding on this open frame form. The design has two cross frames that connect the side frames to each other to break up what would have otherwise been open space. The design becomes more visually interesting while the cross frames support an inner shelf. Alice can use it to keep a book or magazine on while keeping the top clear for something more important. Like a glass of wine for instance.

Alice and I agreed on price and terms this week. Work will begin right after I complete building something to prototype several design and construction concepts to be used in another project. More on that in the following post.

Relevant LinkedIn News

LinkedIn periodically sends me an email with a list of links that it thinks I might be interested in. I received one such today with a number of links to articles that I thought were relevant to this blog.

The first links to an article written by Jeffrey Immelt and his thoughts on the future of productivity and the economy. Of particular interest to me was his take on reversing the trend of outsourcing and its detrimental effect on core competency. He also points to what I find is the compelling use of 3D printing as an advanced manufacturing process rather than how it is normally used as a design modeling tool.

The second covers some of the benefits of working at a coffee shop. All of us in academia whether faculty, staff, or student know how changing up an environment can support a particular effort or project. I took the photo above inside one of the coffee shops on campus that I frequent most often.

And the last is about the connection between the arts and science in education which is essentially what this blog is about, especially when you look at the nature of my work. Here below I provide links to these online articles.

1. Why We're Betting on Manufacturing

http://www.linkedin.com/today/post/article/20130207143128-230929989-why-we-re-betting-on-manufacturing?ref=email

2. Why You Should Work From a Coffee Shop, Even When You Have an Office

http://lifehacker.com/5979758/why-you-should-work-from-a-coffee-shop-even-when-you-have-an-office?utm_medium=linkedin&utm_source=dlvr.it&goback=.gde_49680_member_210306369

3. Education: The Focus on Science Shouldn't Make Us Forget the Arts

http://www.linkedin.com/today/post/article/20130207220042-10842349-creativity-s-role-in-education