The sad state of quality control and products we cut on our SO3


(John Gowrie) #1

I have been noticing more and more lately just what a crappy product PLYWOOD is. I buy hardwood plywood from my local lumber yard and I build all my cabinet boxes with them. Since starting to use my SO3 to machine all my dadoes and rabbets, I’m noticing a shocking difference in the material… not just from sheet to sheet but the SAME DAMN sheets. I’m talking about 1/32" difference in thickness…

Having a discussion over text message with my local salesman from the lumber company and a few quotes which make me just want to ask why I care… You can care but the manufacturers of the products we use just don’t seem to give a crap and make it harder and harder to be a craftsman…


(William Adams) #2

Do you have an option to buy marine grade plywood? It tends to be far more consistent.

Domestic is usually better than imported, and most folks have good quality Baltic Birch.


(John Gowrie) #3

not really. I use Oak, Maple, Birch and occasionally Cherry for my plywoods. I will start looking for the MDF core stuff or the ApplePly brand which is baltic birch but different face veneers based on what you need. I avoid the chinese garbage at all costs… That is why I buy from my local lumber yard because they supply materials produced in North America… however it seems even the NA companies are getting a bit sloppy in what they allow out the doors.


(Anthony Waltz) #4

A few things to remember about any wood product…

Wood is a living, breathing thing. Even after it’s chopped down and dried out and definitely dead, it still behaves as a living, breathing thing. Dead wood will continue to expand and contract, warp and twist, forever. Or until it decomposes into it’s constituent molecules.

Plywood, as a process and as a product, compensates for most of the more wily properties of wood, but it has never been a perfect process. And the companies that make plywood have never promised a perfect product. When it comes to building a project that requires wide, flat panels, plywood is by far a much better, easier to work with, more reliable method for getting wood to be flat than any other method.

Like a fingerprint, every tree is different. Even among the same species. Every part of a tree is different.
Even if you go down to individual cells, they’re all just a little bit different. It’s not like metal or plastic, where it’s all one homogeneous mass of matter. Plywood manufacturing uses machinery that can’t perfectly adapt to all of these differences. That machinery is designed to get as much good material out of the tree as possible, which, in some cases, may not be a whole lot.

Some companies are better than others. They produce a higher quality product, but with that comes a higher price and usually less availability. It takes time to implement the kind of quality assurance you’re asking for. Time being money makes quality more expensive. It’s also harder to find high quality plywood because they don’t make nearly as much of it as the cheap stuff. They don’t make as much high quality plywood because fewer people are willing to pay for it.

I don’t think it’s a question of companies “not caring” about the quality of their products. Its more of a question of customers not being willing to pay for the better quality stuff. Is it frustrating when you can only find low quality Chinese made plywood at the big box store? Sure it is. But a whole lot of people out there are buying it up like crazy. If I were a plywood manufacturer and my A grade plywood is sitting on the shelves, waiting for a discerning customer to come along, and my C grade plywood is flying off the shelves, of course I’m going to make more of the cheap stuff. I might even limit my distribution of the A grade plywood to a few specialty stores where I know it’s actually going to sell, and use that shelf space at the big box stores to put even more cheap plywood out there.

The other issue is that you’re putting this plywood on a machine that’s accurate within a few thousandths of an inch (or better depending on how much time you’re willing to use to dial it in) and expecting the plywood to match that level of accuracy. There’s no plywood on the planet that’s going to be that good. MDF comes close, but still… To say that it’s because plywood companies just “don’t care” about their product any more is completely absurd. It sounds to me like you just need to adjust your expectations to the material that you’re using. If your dados are coming out to wide, adjust your program and recut or glue in some thin strips of wood to make up the difference. If you dados are too narrow, then break out the sanding blocks. All joinery, regardless of whether it’s made by CNC or power tools or hand tools, requires fit up and adjustment. The plywood manufacturer can’t do anything to help you with that.


(John Gowrie) #5

I understand everything you said… I also agree that I have to back off my expectations of what I can do with Plywood now that I am putting on my CNC and machining it for parts.

HOWEVER… I probably should have included the images I took which show the difference between two sheets of Plywood that came from Roseberg ( a domestic producer of Plywood ). If I can’t expect a company to kick out a product that won’t exhibit this level of variation then I guess I just need to stop using plywood all together.

This image shows a rabbet cut ( .7187 deep in from the edge ) and the piece of plywood that fit. Near perfect.

This next image shows the same bottom piece ( the .7187 ) rabbet but the piece I tried to fit into the rabbet was damn near 3/64 under sized in it’s thickness… that was the ENTIRE sheet. To me, that is not acceptable on any day of the year.

I’ve seen this issue at least 2 times in the last 6 months, same amount of difference. I’ve also seen inner layers of veneer completely delaminated… by the time that is apparent, I’ve got a few hours of work into a project possibly so while the lumber yard is nice enough to exchange that out, I am out far more in time and labor. These sheets have all from DOMESTIC plywood manufacturers and not the crap you buy at Home Depot.

Unfortunately, you are also correct that the cheap stuff is what people want to buy and I don’t even know where I can buy anything better locally. I guess I could travel down in to NYC area but that adds a whole layer of expense above the extra cost of the material. It’s frustrating :wink:


(Dan Nelson) #6

I’ve been pretty happy with Purebond maple plywood from Home Depot. Hardly any voids in the pieces I’ve gotten and thickness seems consistent. I see other reviewers not liking it, and maybe I’ve been lucky. The only issue I’ve had is asking Home Depot to cut a piece in half for me, I’d swear their blade was missing a few teeth and the ones that were there were bent, I lost 1/2" or more on each cut edge…kinda tough to stomach on a piece of plywood you’re paying $60 a sheet for. I won’t have them cut anymore for me.

Dan