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Forum topic by JonC123 posted 04-23-2018 12:42 PM 961 views 0 times favorited 27 replies Add to Favorites Watch
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JonC123

10 posts in 184 days


04-23-2018 12:42 PM

Topic tags/keywords: planer jointer shaping

I’ve built a couple of ugly, crooked bookcases and shelves before but I’m really new to woodworking and building things in general.

My next project I want to start is a simple cabinet with some sliding drawers, no doors on it and nothing to fancy.
My goal of the project is just to get some practice, learn, and maybe turn out a nice end product.

I have it designed out on paper and the drawers will be 30” wide and 20” deep. I gave 1/2” on each side for the rails/sliders. So the cabinet should have an internal width of 31” to fit everything and an outer width of 32 1/2” using 3/4” for the cabinet shell.

My first question: Since I need 3/4” wood for the cabinet do I buy 1” to start with? I know wood is smaller than it’s advertised dimensions, so how do I shop for the correct wood? Is all wood this way or just crappy lumber?

Second question: I’ve also read that all lumber needs to be straightened and squared before using for when accurate measurements are important. Can you buy lumber that is already corrected or should you always cut, jointer, and planer your wood?

Thanks!
Jon


27 replies so far

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bilyo

349 posts in 1252 days


#1 posted 04-23-2018 03:09 PM

Very good questions. Whole books have been written trying to provide good answers. Here are some observations based on my experience and readings:

Don’t confuse “dimension” lumber (2×4s, 2×6s, etc sold for building construction) with hardwood lumber. Hardwoods are sold by quarters: 3/4, 4/4, 6/4, etc. These are rough cut dimensions and are true except for any small changes that occur due to shrinkage or expansion after cutting. If you start with rough cut hardwood lumber, you will need to plane it smooth and square. So, you will end up with thicknesses somewhat less than what you start with. So, if you want to build your project out of 3/4” lumber, you will need to start with 4/4 rough cut and plane it straight and square. If your rough lumber is nice and straight to begin with, you may end up with 7/8”. You can leave it there or take it on down to 3/4”. Your choice. You can buy lumber that is already “dressed”, but you will usually pay a premium and, by the time you get it, it may require even more work before it is usable for your project.

Don’t get too hung up on final dimensions. Straight, square, and consistent are more important than actual dimension. For instance, if you want the top of your cabinet to be 1” thick, it probably won’t matter if the glued up panel ends up 15/16” or 1 1/6”. The important thing is that the edges of the boards that make up the top have square edges so that the glued up panel ends up flat and square.

Build your casework first and make sure it is square in every direction. At this point, you can accommodate any interior dimensions you end up with. You are planning a drawer width of 30”. Say your opening after the casework is done is 30 1/8” So what? You build your drawer accordingly. In other words, cut to fit. Don’t blindly cut to dimensions. You will find that once your casework is done, your paper plans are for guidance only. From that point, you are going to check all “actual” dimensions and cut to fit.

Minimize the use of tape measures or rulers. If you need to transfer a dimension from one place to another, use a straight stick marked with a sharp pencil or knife. You will be more accurate and consistent. When you do use a tape or ruler, always use the same ones throughout the project.

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JonC123

10 posts in 184 days


#2 posted 04-23-2018 03:24 PM

Thanks for the info and advice Bilyo!

I planned on investing in a planer and jointer anyway just wasn’t sure about the differences in the woods and if it was always a requirement.

Makes sense about starting from the outside and working my way in to make sure everything fits, even if it wasn’t to my initial drawings dimensions. Instead of cutting every piece then trying to make them fit together.

Side question to that however, what if you’re building something like a dresser that holds 5-dvds width-wise. You would need to make sure that the drawer can hold 5. For this scenario, would you start from the inside (drawers) and build outward? Same concept I guess but not sure if it would have the same result.

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Loren

10477 posts in 3797 days


#3 posted 04-23-2018 03:38 PM

When you buy rough lumber, or dimensioned
hardwoods, it’s sold in 1/4” increments. To
get a 3/4” board you need 4/4 lumber because
that’s how the thick the sawmill is set up to
cut it. After sawing it is dried and it distorts
as it does. Also, there are saw marks on it.
When you buy “surfaced” 4/4 hardwoods they’ve
typically been run through a double-sided
planer. Some of these machines may do a better
job than others at removing distortions from
boards. If you’re going to use this wood for
making cabinets its important to choose the
straightest pieces. It’s often actually 13/16”
thick but that doesn’t allow much material to be
removed if there’s a distortion.

If you look over your surfaced 4/4 boards carefully
with a straight edge and winding sticks you can
probably get some true enough pieces to make
your cabinet out of dressed boards. Your yield
of usable large pieces will be higher if you joint
and plane it yourself though.

Many woodworkers get by without a jointer but
a thickness planer is a tremendous labor saver.
I’ve flattened plenty of boards with hand planes
and while it can be a workout it’s not unbearably
tedious. Thicknessing them by hand is a lot more
work than flattening one side to put them through
the planer.

View Woodknack's profile

Woodknack

12373 posts in 2529 days


#4 posted 04-23-2018 03:58 PM

Good advice above. One more tip, spend a lot of time selecting wood and a lot more time deciding which board goes where. Consider figure, grain direction for planing, matching grain at joints, etc.

-- Rick M, http://thewoodknack.blogspot.com/

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Smitty_Cabinetshop

15584 posts in 2767 days


#5 posted 04-23-2018 05:56 PM

Jon-

If you want to build something simply, but well, I’d suggest pine 3/4” stock that is ready to go. Select the best boards you can find from Lowes or HD or wherever, and build away. Unless you buy roughsawn lumber to get oak, or cherry, or walnut, or etc. etc. that needs to be dimensioned / trued, stuff at the lumberyard can do for this initial project. Keep it simple, emphasize what you’re after: solid joinery, accuracy, function. Save the rest (planing, squaring, etc.) for the next one, or maybe the one after that.

My .02, good luck!

-- Don't anthropomorphize your handplanes. They hate it when you do that. -- OldTools Archive --

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bilyo

349 posts in 1252 days


#6 posted 04-23-2018 06:09 PM


Side question to that however, what if you re building something like a dresser that holds 5-dvds width-wise. You would need to make sure that the drawer can hold 5. For this scenario, would you start from the inside (drawers) and build outward? Same concept I guess but not sure if it would have the same result.

- JonC123


When you have specific inside dimensional requirements it certainly adds a level or two of challenge. The need for accuracy in your measurements will be increased. However, there will usually be places that will provide some flexibility such as in the width of dividers, thickness of drawer sides, etc. A 16th here and a 32nd there adds up. It is common for builders to sand and/or plane the sides of drawers to get them to fit and operate smoothly. And, of course, you can always shave down the edges of your DVD cases. ;>)

I don’t think that I would change my process of working from outside to inside. But, it is always a good idea to do a dry assembly to check critical dimensions before glue-up. It’s even more important in this scenario.

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JonC123

10 posts in 184 days


#7 posted 04-23-2018 07:32 PM

Thanks for all the help everyone. This has been super helpful as to re-align the way I think about measurements. Now that I’m armed with all this new knowledge I’m going to practice creating some boxes to size!

View darthford's profile

darthford

612 posts in 2073 days


#8 posted 04-23-2018 08:29 PM

Measure twice, cut once, trust me on this. Make sure your saw blade kerf is outside of your cut line.

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John Smith

1379 posts in 312 days


#9 posted 04-23-2018 08:51 PM

another tip: if there is a knot or imperfection in a board that you don’t like,
don’t use that one where it will show or cause you grief later on because you don’t like it.

[ and if you overthink it ~ it will surely be overthunk ]

,

-- I started out with nothing in life ~ and still have most of it left.

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Woodknack

12373 posts in 2529 days


#10 posted 04-23-2018 09:32 PM

Precision nearly always trumps accuracy.

-- Rick M, http://thewoodknack.blogspot.com/

View bilyo's profile

bilyo

349 posts in 1252 days


#11 posted 04-25-2018 06:47 PM



Precision nearly always trumps accuracy.

- Woodknack


I’m assuming that you are serious. The following website has this statement:
“Results can be precise without being accurate. Alternatively, results can be precise AND accurate.”
https://www.diffen.com/difference/AccuracyvsPrecision
In woodworking, I would rather be accurate.

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Woodknack

12373 posts in 2529 days


#12 posted 04-26-2018 07:34 AM



I m assuming that you are serious. The following website has this statement:
“Results can be precise without being accurate. Alternatively, results can be precise AND accurate.”
https://www.diffen.com/difference/AccuracyvsPrecision
In woodworking, I would rather be accurate.

- bilyo

Of course I am serious. Accuracy is the ability to hit a specific measurement. Precision is the ability to make identical pieces. Precision is more important, most of the time. That doesn’t mean accuracy isn’t important, it means precision is more important when you are making multiples of something. You make things that need to be the same, the same. If making a bookcase, you want the 2 opposite sides to be the same. It doesn’t matter if it matches a number on a piece of paper, it matters that they are the same.

-- Rick M, http://thewoodknack.blogspot.com/

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bilyo

349 posts in 1252 days


#13 posted 04-26-2018 02:47 PM

By definition, being precise alone does not mean you are being accurate. One example given is in target shooting. If you shoot 5 shots into a cluster to the upper right of the bullseye, you are being precise, but not accurate. If your cluster is in and around the bullseye, you are both. If you are cutting 6 pieces the same length and set your stop block inaccurately, you will be precise in your cuts, but you will not be accurate. You may be correct in your example that it really doesn’t matter as long as they are the same. The only reason that is meaningful is because there is no standard you are measuring against (you’ve determined that accuracy is not important in this instance). However, If you had been cutting pieces to fit between two fixed components then you might have been precise in making your cuts, but you could have been precisely wrong if you had not also been accurate.

Determining the importance of precision over accuracy should have nothing to do with the frequency you perform one type of cut or another. Any such discussion should be divorced from situations where one or the other is deemed unimportant to achieve an end result.

Interesting discussion. The bottom line is that one can be consistently wrong (inaccurate) and still be precise. However, if consistently accurate you will also be precise.

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Woodknack

12373 posts in 2529 days


#14 posted 04-26-2018 04:39 PM

Woodwork is not machining. It doesn’t matter if a table leg is 29” or 29-1/32, what matters is that all 4 legs are the same. Ditto for case sides.

-- Rick M, http://thewoodknack.blogspot.com/

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bilyo

349 posts in 1252 days


#15 posted 04-26-2018 05:14 PM

You are correct in your example, but that is not ALL that matters ALL the time. I think you miss the point of the discussion.

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