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Forum topic by MrRon posted 10-12-2018 10:10 PM 746 views 0 times favorited 20 replies Add to Favorites Watch
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MrRon

5576 posts in 3666 days


10-12-2018 10:10 PM

Plywood used to be manufactured to even fractional sizes, such as 1/4”, 1/2”, 3/4” etc. At some point, the face and back veneers got thinner and thinner making the present plywoods a 1/32” less making it 23/32” instead of 3/4”. The same went for all other sizes. Why didn’t they adjust the core veneers thicknesses in order to maintain 3/4”??? Working with an even 3/4” thickness makes woodworking much easier. In a world that runs on standardization, plywood seems to have dropped the ball. Chinese plywood appears to be made without a standard. I have measured Chinese plywood and the thickness can vary quite a bit; enough to make a dado joint too tight or too loose.


20 replies so far

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BroncoBrian

875 posts in 2381 days


#1 posted 10-12-2018 10:17 PM

You are correct sir. Dados and plywood require adjustments even within the same sheet if you want precision. I am noticing more air pockets in plywood lately.

-- A severed foot is the ultimate stocking stuffer.

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Rayne

1209 posts in 1962 days


#2 posted 10-12-2018 10:28 PM

Even the higher quality Baltic Birch isn’t 3/4”, but much closer than most of the other plywoods in my area. Even 23/32” isn’t really 23/32”...sad but true.

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Richard Lee

245 posts in 1198 days


#3 posted 10-12-2018 10:33 PM

Gotta save a penny or 2 somehow.Soon a 2×4 will be 1 1/4 by 3
Never ends.

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lumbering_on

578 posts in 912 days


#4 posted 10-12-2018 10:35 PM

Can’t speak to the Chinese plywood, and I’d rather it didn’t exist. However, there is a major cost advantage with making plywood a bit thinner.

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johnstoneb

3117 posts in 2595 days


#5 posted 10-12-2018 10:41 PM

Plywood went metric.

-- Bruce, Boise, ID

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ArtMann

1399 posts in 1239 days


#6 posted 10-13-2018 02:02 AM

Baltic Birch is called that because it is imported from the Baltic countries of Eastern Europe. It has always been manufactures to metric sizes.

I have something of a historical perspective on plywood because I started building stuff with it around 1975. It was not the nominal size then either. I salvaged some plywood for shop cabinets that came out of a 1950’s grocery store. That material was a true 1/2 or 3/4 inch as best I could tell. I still have a cabinet made out of it.


Even the higher quality Baltic Birch isn t 3/4”, but much closer than most of the other plywoods in my area. Even 23/32” isn t really 23/32”...sad but true.

- Rayne


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MrRon

5576 posts in 3666 days


#7 posted 10-13-2018 02:28 AM

True Baltic birch comes only in 60” x 60” sheets and is measured in metric. A 4×8 sheet of birch is not Baltic birch.

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Dark_Lightning

3471 posts in 3531 days


#8 posted 10-13-2018 02:35 AM



True Baltic birch comes only in 60” x 60” sheets and is measured in metric. A 4×8 sheet of birch is not Baltic birch.

- MrRon


Sure looks like it though, with the two outside plies the same thickness as the other plies, and not some 1/(whatever you can see through) thickness veneer. You may only be seeing it in 5’X5’ sheets where you are, but when I worked for LADC (Skunk Works) we bought it in 5’X10’ sheets (well, the metric equivalent thereof) in many thicknesses.

-- Random Orbital Nailer

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Aj2

2321 posts in 2220 days


#9 posted 10-13-2018 04:48 AM

I don’t buy plywood very often but when I do I get Baltic birch. I really like the way it smells. The place I buy it from has it unfinished and finished. The unfinished stuff seems nicer.

-- Aj

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Woodknack

12845 posts in 2803 days


#10 posted 10-13-2018 03:48 PM

My house was built in ‘69, my shop sometime after, both built with true fractional plywood. Also the 2x lumber is actual size, 2×8 is 2” by 8”.

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

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PropmakerLA

13 posts in 433 days


#11 posted 10-13-2018 04:56 PM

A lot of the products we use come from china. We call it 3/4 MDF but its stamped 18mm, what we call 1/2in is really 12mm. So I guess a lot depends on where the products are manufactured.

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Kazooman

1328 posts in 2375 days


#12 posted 10-13-2018 05:09 PM



True Baltic birch comes only in 60” x 60” sheets and is measured in metric. A 4×8 sheet of birch is not Baltic birch.

- MrRon

True. What always struck me as odd is the size of the sheet is in Imperial inches and the thickness is in metric millimeters. Talk about mixing apples and oranges!

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000

2859 posts in 1322 days


#13 posted 10-13-2018 05:42 PM


True Baltic birch comes only in 60” x 60” sheets and is measured in metric. A 4×8 sheet of birch is not Baltic birch.

- MrRon

True. What always struck me as odd is the size of the sheet is in Imperial inches and the thickness is in metric millimeters. Talk about mixing apples and oranges!

- Kazooman


Damn, my lumber yard has been lying to me for years. What a fool I am.

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MrRon

5576 posts in 3666 days


#14 posted 10-13-2018 08:09 PM


True Baltic birch comes only in 60” x 60” sheets and is measured in metric. A 4×8 sheet of birch is not Baltic birch.

- MrRon

Sure looks like it though, with the two outside plies the same thickness as the other plies, and not some 1/(whatever you can see through) thickness veneer. You may only be seeing it in 5 X5 sheets where you are, but when I worked for LADC (Skunk Works) we bought it in 5 X10 sheets (well, the metric equivalent thereof) in many thicknesses.

- Dark_Lightning


You were probably getting a special order due to commercial purpose. Did you work with Kelly Johnson?

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000

2859 posts in 1322 days


#15 posted 10-13-2018 08:44 PM

https://www.wolstenholme.com/plywood-products/baltic-birch/

Russian Birch plywood is uniquely manufactured with multiple ply’s of Birch veneer, used uniformly, throughout the panel. Each layer of birch veneer is peeled at 1.3mm or 1.5mm thickness giving the panel a multi-ply edge that is both aesthetically attractive and offers unmatched strength and stability. Birch plywood from Russia has been available in the United States for over fifty years, and still today, goes by the trade name of Baltic Birch. Historically, only available in 5’x5′ sheets, today Russia has expanded production to include numerous other formats, such as 4’x8′ and 10’x5′ and 10’x4’.

It doesn’t have to be special ordered. You just have to have a descent lumber company that stocks it.

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