Thickness
#11
I have some plans for a barristers bookcase. The plans call for quartersawn white oak, 3/4" thick. I finally located some, but of course had to plane it down. I have it at .753". When planing boards to size, what do yo consider close enough? + or - .005, or do you strive for perfection, every time? Would you rather be slightly over or under?
I'll probably have a lot of stupid questions like this. I really appreciate your patience.

Thanks Greg
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#12
Greg,  no such thing as a stupid question.  I would not worry too much about it being slightly under or over.  Usually, we make pieces to fit each other-  it is not like assembly line for manufacturing, where you are making pieces that are interchangeable.  You make it one bookcase at a time, and if the shelf is to fit a dado, you trim one or the other to fit, whether it ends up .750,  .760 or .740 doesn't matter.  BTW,  I assume you are using a surface planer, right, if not post back.   Any other questions, just post them,  everyone was a newbie at some point.
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#13
(05-09-2022, 07:11 PM)Gregor1 Wrote: I have some plans for a barristers bookcase. The plans call for quartersawn white oak, 3/4" thick. I finally located some, but of course had to plane it down. I have it at .753". When planing boards to size, what do yo consider close enough? + or - .005, or do you strive for perfection, every time? Would you rather be slightly over or under?
I'll probably have a lot of stupid questions like this. I really appreciate your patience.

Thanks Greg

There are occasions in woodworking where that last decimal place matters, but not many of them. I would be very surprised if it made the slightest difference. 3/4" is a convenient round number, but that's all it is. Depending on the design, it. might matter how identical the board thicknesses are (or not, really depends on how it is constructed). 

You should be good to go.
Best,
Aram, always learning

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” Antoine de Saint-Exupery


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#14
Consistency is more import to me than the actual thickness

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#15
My opinion is that consistency helps more than extreme accuracy. If all of my 3/4 boards come out consistently the same thickness, it makes some things easier.
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#16
Put the calipers up and measure with a tape or ruler.  This is wood working, not metal working.
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#17
(05-09-2022, 08:45 PM)lincmercguy Wrote: My opinion is that consistency helps more than extreme accuracy. If all of my 3/4 boards come out consistently the same thickness, it makes some things easier.

.753 is plenty good.  You can sand off .003 rather easily and even then for woodworking, that's plenty good.  For internal parts on an aircraft engine, that's pretty sloppy, but we're not doing that kind of thing here.
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#18
Did you know that when you measure the thickness next week it might be a perfect .750"? Then again; it might be .756".
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#19
(05-09-2022, 09:21 PM)MstrCarpenter Wrote: Did you know that when you measure the thickness next week it might be a perfect .750"? Then again; it might be .756".

Exactly, if the moisture content of the wood changes, so will the dimensions, maybe by up to 1% depending on your seasons and climate. Good furniture designs allow for this movement, and you will see in your bookcase plan that there are no large "cross grain" joints, plus q-sawn wood moves less in width than other cuts. 

But as others have said, "Sameness" is what you want. If you a gluing up a table top for example, it doesn't really matter if it's 0.74" or 0.76", as long as all the boards are the same. Same with the legs, you don't have to get the length "exact" to the last 1/1000". You have to get all the legs the Same length. 

What I do on a project is make the final planer pass on all the "same" pieces in one run. That means they should all be about the same moisture, and same planer setting, 

The 3/4" is just a convenient number. Boards rough sawed at 1" (fractionally over to meet grading specs) should shrink as they dry, and still allow enough to plane down to 3/4". So plans and jigs / tools are made with this in mind. Here we rough saw to 25mm (0.984"), and plane to 19mm (0.748"). But no one normally measures that close, because next week the numbers will have changed
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#20
(05-09-2022, 08:56 PM)Bob Vaughan Wrote: .753 is plenty good.  You can sand hand plane off .003 rather easily and even then for woodworking, that's plenty good.  For internal parts on an aircraft engine, that's pretty sloppy, but we're not doing that kind of thing here.


Big Grin
Best,
Aram, always learning

"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.” Antoine de Saint-Exupery


Web: My woodworking photo site
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