Quiz Questions: Part I
In this design I considered a variety of issues for woodworkers of all levels to consider. Some considerations surround the joinery while others consider the use of tools. In any product design using solid wood, and this project uses only solid wood, the designer must consider such things as shrinkage, swelling of wood fibres, things like these. To answer my questions requires a broad base of basic understanding of hand tools and their applications, joints and their functionality. No need to kick this can down the road so let’s see where we end up!
My answers are lower on the page. Scroll down when you are ready to see them. Get your pencil and paper and see how well you do.
Questions
Question 1: The main body of the project has three common names furniture makers often refer to to describe the superstructure. Can you name two of them?
Question 2: The sides, top and bottom have the grain oriented all in the same direction. Why did I choose to orient the grain this way and not horizontally for the sides?
Question 3: Why did I use such a narrow stepped housing dado, 1/4″ (6mm) instead of a full width one the thickness of the whole side piece of 3/4″ (20mm)
Question 4: The back panel is different to the sides in that it is grooved into the top, bottom and side pieces. Is there an advantage to this?
Question 5: Is there a reason not to use screws alongside the housing dado, to ensure the joint remains together?
Question 6: Why did you use roundovers to the four edges of the top and bottom pieces?
Question 7: The guide supports for the drawer to run on rely only on screws. Wouldn’t it be better with some kind of housing dado or other joint for this?
Question 8: The drawers themselves have the grain running in the opposite direction to the box. Does this not then compromise the project because if the carcass shrinks the drawers will protrude past the front. If it expands, the drawer fronts will sit below the surface surrounding the drawer?
Question 9: I don’t see any end to the housing dadoes front or back. What if the sides shrink or expand more than the top and bottom? Will there be a gap?
Answers
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Answer 1: Carcase, case or cabinet.
Answer 2: So that expansion and/or contraction (shrinkage) would all take place in the same direction (across the grain) and so without conflict that leads to stress and cracking. Grain does not shrink or expand noticeably in its length but across its width the expansion and contraction can be expansive and increases the wider the boards.
Answer 3: I wanted to minimise any distance of shrinkage. The narrower the housing dado the narrower the interconnecting ‘tenon’ part and so the minimal amount of shrinkage will take place. I also wanted to distance the rim of the housing dado from the outer corner edge of the top and bottom pieces to increase the length of continuous grain the outer area relies on which then increases the intrinsic strength of the surrounding outer support wood. Also, the step over the outer line of the housing dado is hidden inside the step so that no gap can ever be seen at this juncture.
Answer 4: The advantage is that we have created a carcass that holds what we usually call a floating panel. The panel is not fixed or glued in anyway but it is housed in on all four edges of the panel. This allows the panel to expand or contract according to the atmospheric moisture content (AMC) which minimises the risk of splitting. The grooves also constrain the panel and so prevents the panel from future warping.
Answer 5: You can use screws if you wish to however it will prove unnecessary as the glue surfaces to the joint span 1 1/4″ and this should prove sufficient. Screws usually need hiding with plugs of some kind which is just another added step too.
Answer 6: For two main reasons: The first reason is to remove the hard corners which tend to fracture when knocked. I could have simply planed a 45-degree corner off but the project would still look too heavy and clunky so my second reason for the roundover is to lighten the finished appearance of the project. Of course I could have used thinner wood but I felt I needed the bulk to ensure and solid joinery construction with built-in longevity. Because I envisage moving the piece around my workshop according to convenience, it is easier to handle with the rounded edges.
Answer 7: We chose not to glue these supports so that the sides can still expand and contract. Two or three screw securing the supports is more than adequate and the allow the sides to expand and contract.
Answer 8: I made the drawer half an inch shorter than the sides of the case and installed stops distanced from the front edge of the case the thickness of the drawer fronts. This enables me to align the drawer front with the surrounding superstructure and set the distance I want for the two drawer stops from the front of the drawer line to the back of the drawer front. This means that the drawer front always aligns perfectly.
Answer 9: The housing dado stops 3/4″ from both front and back edges of the sides so the corners are stepped to the same depth as the housing dado. This then hides any possibility of a gap occurring at any stage.
This was somewhat difficult as I wasn’t sure, based on the introductory paragraph, what piece of furniture or project the quiz was referring to. The questions are specific about a particular project, which isn’t identified. Is it the two drawer organizer? If so, I have no idea how it’s built yet (can’t wait for the video!). Otherwise, I did guess fairly well on some of them. I like this Quiz other than the confusion. Would like to see more of this!
Evidently you did not read the last paragraph of the previous Blog entry.
“So, why Value Added Quiz. Tomorrow I am going to ask you questions about my decisions in the design and making of this project. To see if you can answer the key issues I built into the design. We’ll see how you fair!”
JIM
Love it.
Great format, I learned a lot!
Could you add a video showing how to draw the project. It would be great to have the perspective view. It would also be nice to learn how to properly draw the detailed drawings with the measurements.
I agree, that would be helpful. Normally I would rely on a program like Sketchup or something like that, but I like to have the option to not touch a computer if I don’t have to.
I agree! It could be very educational for many of your followers, including me.
I did realize from the previous email that this was in relation to the tool organizer but agree, another picture in this email to reference would have been helpful.
I don’t see where a schematic has been released yet which also would have been helpful, for example with question 3.
Other than those observations, this was awesome and provided a lot of additional insight. I know it’s more work but something like this would be really nice to be able access with any of your future video series.
I say that realizing some things would get repeated maybe from previous projects but would still be helpful….especially in terms of doing things certain ways the relation to expansion.
I remember on the crib you had a stopped dado but the recess was angled for some reason vs the 90 degrees as I had seen with the past projects.
Anyway….really appreciated this and found it helpful for some of the questions I already had, short of seeing the video series.
Not to quibble, but in question # 1 is it “carcass” or “carcase?” I’ve always found the second spelling an oddity when referring to a “carcase saw.”
Predictive text. Sorry, I guess there is more use of carcass than carcase Corrected now.
Both spellings are used with same (multiple) meanings, but carcass appears to be more common these days, isn’t it?
I really like the quiz, or question/answer format. It helps to more fully understand design details and what goes into the decision making process. I would certainly be open to this format going forward, as it is another angle or facet of the teaching/learning experience — and its reinforces what already is being shown to us. Keep up the great work, Paul.
That really was some good clean fun. I especially enjoyed the open-ended nature of the questions – the ‘why’ often being more interesting than the ‘what’ or ‘how’. Thanks for thinking outside of the box and running with such an original idea for a blog entry. I’m quite tempted to invest the time in making such a chest.
I liked the questions very much because you need to understand how to account for wood movement. I have to agree that a sketch would have made it clearer. For instance I still don’t understand where the drawers run on screwed in supports are there slots in the drawer runners so it will be allowed to move? Are the runners made out of a harder wood for more wear from a different wood that might expand and contract differently?
I still have no idea what you are talking about on question 9. I’ll have to wait until I see how it’s put together. If the grain was running up and down on the drawers wouldn’t it be very weak? I would also think they would move or warp a lot.
The runners are installed with the grain running perpendicular to the grain on the sides. When the sides expand the runners won’t as much and if the joint was glues then something would crack.
Question 9 would be clearer with a drawing or picture but in essence, the housing dado doesn’t go all the way to the edge of the wood so you would never see if it opened up from expansion
Great quiz, but I’m not going to put too much time into it until I can see more of the project. That said……I think this is a great start to helping us followers start thinking more about the design process.
Confused about #3.
The answer for question 7 doesn’t fully answer the question. Why not a housing dado? My only thought is that it might be overkill. But I’m not the expert. 😉
Thanks,
Jason
The answer explains why its not glued and that refers to the housing dado which will require glue.
Combination of dado and screws is what I was thinking… But I get your point. Thanks Selva.
Jason, I believe you were right originally. There’s nothing wrong with a housing, if done properly. Properly would mean not gluing the entire length. Instead, you would just glue the first couple of inches at one end. The other end could be secured with a screw in an oversized or slotted hole. Or, the other end could tenon into a mortise in a rail going side to side across the back with the tenon left unglued. See, for example, Paul’s cherry chest, if I recall correctly. There are even more options for ways to do this with a housing. Paul’s point, I believe, was that this all would be more than is necessary for this small piece, so he simply screws the drawer runners to the sides.
Ed,
That’s exactly what I was thinking… If you store something heavy in the drawer, the housing dado would give it more mechanical strength.
I still don’t understand the answer to question 7 about fixing the guide supports only with screws. Wouldn’t you fix the sides in place with the screws, effectively preventing wood movement in this cross grain situation? You would have to use at least 2 screws, trapping the wood between 2 fixed points. Why would this not be an issue?
It’s a good question. If you sat an exam the examiner might well say the same thing. In reality however, the screw hole bored through the support guide allows for movement because there is flex both by the slightly oversized hole and the fact that wood also absorbs pressure at the fixed screw points, albeit bruising, and the screw themselves will also bend too. In my practical experience I would say the wood would have no problem expanding or contracting 3-4mm without any issue of cracking. You see the wood is not as you say trapped between two points as such. There is natural ability to actually flex and it works fine. In other words the “2 fixed points” are not as “fixed” as people say or think.
What are the alternatives for no screws at all anywhere in the organizer and if there are alternatives, would they negatively affect the overall design?
There are several but none with the same advantages screw provide. You don’t need to use screws anywhere if you don’t want to. I am not sure what the advantage of that would be as screws are indeed one of the most amazing technical advancements of modern engineering.
Good format.
Great! Loved that I had to think about those questions. I get so caught up in the working of wood that I forget the design and structure elements. Us amateur woodworkers keep on learning. Every day! Thanks Paul