1/2" Baltic Birch.......Wait, not so fast.

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Forum topic by cranesgonewild posted 02-20-2011 01:06 AM 10770 views 0 times favorited 32 replies Add to Favorites Watch
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344 posts in 3550 days

02-20-2011 01:06 AM

Topic tags/keywords: baltic birch 12 plywood jig kreg jig kreg

I was in the local big box store to buy some 1/2” baltic birch plywood a few months ago. I’ve learned from my past experiences to carry a tape measure on me when I buy wood. I bought a piece that was 2’ x 4’ x 1/2”. The UPC on the plywood said 1/2”, but the label on the shelf said 11.5mm (which is about 1/16” shy of 1/2”). I measured it, and sure enough, it was 7/16”(11.5mm) thick.

I want to know. Is this a Canadian thing, seeing that I’m here in Canada and we’re suppose to go by the metric system, which I don’t. Is it the same in the States?

If so, why is it that plywood companies do this? Why can’t they just leave it at 1/2” thick? Is it the cost, because I’ll pay for the extra 1/16”. It really screws me up sometimes when I’m going by a certain set of plans, and I have to change the numbers because of the thickness.
I ran into this problem again in my latest project when I made the Kreg Jig Workcenter. I went with MDF for the stock supports for the top of my lid because I needed 1” thickness so it would be level with my Kreg jig. I could have used 1/8” wood veneer and sandwiched it between the two pieces of baltic birch, but I didn’t want to go that far.
The plans in magazines such as WOOD and WoodSmith call for 1/2” sometimes, so it must still exist.

So my question is,
Is it the same in the states?
And is there any such thing as 1/2” baltic birch anymore?

-- I'm a Fungi --

32 replies so far

View Karson's profile


35212 posts in 5042 days

#1 posted 02-20-2011 01:12 AM

I think this is lind of like selling Ice Cream in 1.5 or 1.75 quarts. instead of 1/2 gallon. It to raise the price by giving a smaller package.

The plywood mfgs have just made them thinner to get a higher price for their materials. They may reply because it was to standardize on a metric scale. But they didn’t reduct the price to do

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

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Blue Mountain Woods

110 posts in 3576 days

#2 posted 02-20-2011 02:10 AM

Actually, it’s because of the unavoidable inconsistencies in the manufacture of plywood. All plywoods (lumber core, MDF core and plycore) are made using heat and glue. Wood being what it is, this causes lots of variation (as much as .022” on lumber and ply core sheets) in the finished thickness, one corner to another on the same sheet. They can’t just sand it flat, because veneers can be as thin as 1/100th” on the cheap stuff, and still only 1/40th” on the good stuff.
The reasoning for its finished thickness is that the finished sheet can be a bit thinner than nominal (to say, fit into a slot that you cut for it) but not thicker.

-- Pete -----

View Dark_Lightning's profile


3811 posts in 3751 days

#3 posted 02-20-2011 03:42 AM

I just went and measured an old piece I bought in 1997, and it’s .251” +/- a couple thou, all four corners. The sheets I bought earlier this year are .223”. I call cheapness on the manufacturers. I bought both from reputable suppliers, so that’s not the issue.

Based on this, I’m not buying the variable thickness story. Manufacturers’ engineers lose sleep at night over that kind of problem in the quality control.

The irritating thing is making something with dadoes and having the shelves rattle unless you go buy a special bit or make multiple passes with a smaller bit. That’s bad for production. Since I bought the recent purchase at $17 a sheet, and paid $22 for the older stuff, I guess I know why, now. Fortunately, the project I’m making won’t have any dadoes in it, or I’d be real irritated. Guess I’ll start taking my calipers to the wood store. Sheesh, it wasn’t even a Borg store.

Lessee….(251-.223), divided by .223 is about 13% less material. Cheaters!

-- Steven.......Random Orbital Nailer

View Blue Mountain Woods's profile

Blue Mountain Woods

110 posts in 3576 days

#4 posted 02-20-2011 04:29 AM

Well, they charge what they charge. I’m not saying that they can’t make sheetgoods to a closer tolerance; I’m saying that as a manufacturer, I certainly would not, if doing so would raise my production costs enough to price me out of the market. I’m sure that they could manufacture sheetgoods which spec to within +/- .002”, but I’m not gonna pay $250.00 for a sheet of cherry ply, and can only surmise that the manufacturers know that I won’t.
Not being much of a conspiracy theorist, I’m left with the only logical steps I can come up with, and I’ll spend the 40 bucks on the 3-bit set from MLCS. Further, a piece of wood (ply or not) purchased 13 years ago has no relevant comparison with one manufactured recently, even if they each began life at precisely the same gauge. In general, woodworkers (unlike metalworkers) work in increments of .01”, not .001” (although a few feel more secure thinking otherwise), because a piece of wood will vary by .01” or more overnight.
The variable thickness story is a matter of objective physics.
And…’s not a special bit, it’s a standard plywood bit. A 3/4” bit is the incorrect bit to use for a dado for 23/32 ply.

-- Pete -----

View Jeff's profile


518 posts in 3836 days

#5 posted 02-20-2011 04:53 AM

Tolerances wasn’t the point of the original post. Unless 7/16” is acceptable for 1/2”. The point was why do manufacturers make 7/16” and sell it as 1/2”? And why did they go to 7/16” in the first place? Obviously it’s cheaper to make 7/16” and they’ll make more money selling for the same price as 1/2”. Like Karson says a smaller package of ice cream may slip by most of us but when we need 1/2” plywood we need 1/2” plywood and we’d pay for it.

View Raskal's profile


36 posts in 3327 days

#6 posted 02-20-2011 04:56 AM

I agree with AtomJack,... pure greed.

Nothing to do with Metric/Imperial, just a way to make more $$.

View WoodSpanker's profile


560 posts in 4034 days

#7 posted 02-20-2011 05:03 AM

Interesting topic, and one I heard my grandfather and father grumble about when I was a kid way back in the 70’s. So I would say, it is an ongoing problem. My guess would really be a mix of both. You are going to get some manufacturers cheating, and you are going to get some manufacturing inconsistencies. Guess I am what you would call a plywood agnostic. :)

-- Adventure? Heh! Excitement? Heh! A Woodworker craves not these things!

View 8iowa's profile


1591 posts in 4403 days

#8 posted 02-20-2011 05:14 AM

Last year, for a shelving unit, I purchased a 4×8 sheet of “3/4” birch plywood ( Chinese) at Lowes. It measured .686”. This year I added to the project, but this time a contractor friend ordered some USA made birch plywood. It measured .710.

Just think how many dollars are “saved” when companies are making 4×8 sheets by the thousands.

-- "Heaven is North of the Bridge"

View Blue Mountain Woods's profile

Blue Mountain Woods

110 posts in 3576 days

#9 posted 02-20-2011 05:14 AM

I’ve not seen the manufacturers market their sheets as 1/2”, 3/4”, etc. I HAVE seen retailers refer to it that way. Manufacturers generally stamp their sheets. Even at Home Depot, the 3/4” is stamped 23/32.
In 30 years, I’ve never thought that “3/4 inch” ply was 3/4”. It is generally known by any cabinetmaker that ply runs under, and always has. There are some advantages to this, among them being the ability to take cheap 23/32 birch shop, and throw whatever exotic veneer you want on it, and have 3/4.
But…..I digress….... this is one of the few threads I’m gonna check out of; because I don’t understand it (beyond the fact that somebody didn’t know that 3/4” ply is not supposed to be; by design).
Plus…..... if I have some of you right, then I only have to wait 6 more years, and I’ll have a true 1/2” when I buy a sheet of “3/4”. :)

-- Pete -----

View ChunkyC's profile


856 posts in 3896 days

#10 posted 02-20-2011 05:19 AM

It’s my understanding that BB Ply is metric. We call it 1/2” and 3/4” because we use the Imperial system. It’s actually 12mm and 19mm nominal.

-- Chunk's Workshop pictures:

View D_Allen's profile


495 posts in 3426 days

#11 posted 02-20-2011 05:29 AM

So why can’t they offer both?
Some buyers would pay a little more for a full 1/2” if it were available. I know I would
Would it be that difficult to mke both? Just add a core or 2 on part of the run! Seems simple enough…but then maybe I’m just a simple guy!

-- Website is finally up and

View PurpLev's profile


8554 posts in 4290 days

#12 posted 02-20-2011 05:34 AM

1. I don’t think you can find Baltic Birch at the big box stores – unless it’s a special order. what is commonly sold there is Bitch Plywood. Baltic Birch is Birch plywood specifically from the Baltic region and at a very good quality.

That aside – as ChunkyC mentioned – it is sold as 1/2” and 3/4” in the States/Canada because we use the Imperial system here, but it’s actually made for metric. but still – 1/16” off the supposed size is a bit of a stretch.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Mike Gager's profile

Mike Gager

665 posts in 3909 days

#13 posted 02-20-2011 06:04 AM

its been like this for a long time. thats why they make plywood sized straight router bits

View superstretch's profile


1531 posts in 3335 days

#14 posted 02-20-2011 06:06 AM

As I’ve heard it, yes, there’s slightly less material, but performs as well as old school, full-thickness plywood. As far as I’m concerned, a thinner material that performs just as well is a bonus in my book.

-- Dan, Rochester, NY

View jusfine's profile


2422 posts in 3568 days

#15 posted 02-20-2011 06:08 AM

Hey Cranes, I don’t remember ever seeing BB at 1/2”, it’s always been the 11.5mm at my wholesaler’s…

-- Randy "You are judged as much by the questions you ask as the answers you give..."

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