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Forum topic by Travis posted 04-09-2019 07:43 PM 352 views 0 times favorited 8 replies Add to Favorites Watch
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Travis

229 posts in 127 days


04-09-2019 07:43 PM

Hello all,

I’m working on a cart for my table saw. Plan called for 3/4” plywood. I went to the big box store because it was easier and I wasn’t worried about getting top quality—it’s a work surface not fine furniture. That said, there were only exactly enough sheets in stock and some of them weren’t exactly flat.

Any ideas for how I can flatten some of these pieces, or at least get them flatter? Look at the two pieces in the top right of the carcass, for example.

-- Extra screws left over are just evidence I found a better way to put it together.


8 replies so far

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fuigb

558 posts in 3318 days


#1 posted 04-09-2019 08:06 PM

You’d have to show a drawing to know if cutting out the good part (if there’s any) is a feasible option. Cruddy stock doesn’t improve on the ride home, which is why before i’ll pay for anything blemished I have calculated if the piece is worth my trouble. Not much help now that it’s home, but if I’d been with you at the store I’d have recommended a pass and wait until next week and its shipment.

-- - Crud. Go tell your mother that I need a Band-aid.

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Rich

4399 posts in 949 days


#2 posted 04-09-2019 08:43 PM

You’re not going to be able to just flatten them. However, if you’re creative, it won’t matter. One option is to use those pieces for smaller elements of the cart. If you rip them in half, thirds or less, the bow will be less pronounced and probably completely insignificant..

Another option would be to use it for a shelf. Run cleats around the carcass and set that in there bow up. The weight of what you put on there will help flatten it.

If you’re going to be doing dadoes to mount shelves into the carcass, you can eliminate the bow that way. It’ll take some muscle to get it in, but that’ll flatten it for sure.

-- Knowledge is not skill. Knowledge plus ten thousand times is skill. -- Shinichi Suzuki

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Travis

229 posts in 127 days


#3 posted 04-09-2019 08:44 PM



You d have to show a drawing to know if cutting out the good part (if there s any) is a feasible option. Cruddy stock doesn t improve on the ride home, which is why before i ll pay for anything blemished I have calculated if the piece is worth my trouble. Not much help now that it s home, but if I d been with you at the store I d have recommended a pass and wait until next week and its shipment.

- fuigb

Yeah, in hindsight I should have just waited. The problem with me is I’m a hobbyist/DIY’er/weekend warrior. I get infrequent gaps in my schedule where I can project, and I was ready to project when I grabbed those sheets. I don’t have a pickup so I either have HD cut them down to size and/or I rent their truck for $20. It’s a whole production that I have to gear up for. I prepared cut lists and had been poring over the plans for days in anticipation. I did not want to go home empty handed. Still, the adage holds true, “haste makes waste.”

Anything I can do that might help the situation, besides just go back and buy more plywood?

-- Extra screws left over are just evidence I found a better way to put it together.

View Travis's profile

Travis

229 posts in 127 days


#4 posted 04-09-2019 08:49 PM



You re not going to be able to just flatten them. However, if you re creative, it won t matter. One option is to use those pieces for smaller elements of the cart. If you rip them in half, thirds or less, the bow will be less pronounced and probably completely insignificant..

Another option would be to use it for a shelf. Run cleats around the carcass and set that in there bow up. The weight of what you put on there will help flatten it.

If you re going to be doing dadoes to mount shelves into the carcass, you can eliminate the bow that way. It ll take some muscle to get it in, but that ll flatten it for sure.

- Rich

That’s helpful, thanks! I’m still fairly new at this and I wasn’t sure how wise it was to “force” them flat, either through weight-bearing functions or joinery. I was afraid I’d end up splitting it or causing other restricting parts to split.

-- Extra screws left over are just evidence I found a better way to put it together.

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bondogaposis

5368 posts in 2711 days


#5 posted 04-09-2019 09:22 PM

If you are making shelves to store your anvil collection that bow will flatten itself out, otherwise I’m not sure what you can do. As you assemble your carcase, some of that can be pulled out with screws in the corners other wise you are stuck I’m afraid.

-- Bondo Gaposis

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tywalt

36 posts in 524 days


#6 posted 04-09-2019 10:13 PM

I agree with Bondo. Some can be pulled out in assembly, just have to make sure you measure the bow/cup correctly so the flattened ply is the correct size, not the cupped one you started with. I’ve had some luck in a pinch building a super structure (frame) out of scrap 2×4 and screwing bowed ply into it to flatten that way.

Regarding Rich’s comment, cutting down a cup/bowed piece can often make the warp more pronounced in my experience. However, the less material there is, the easier it will be to straighten it out with screws as previously mentioned.

-- Tyler - Central TX

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Rich

4399 posts in 949 days


#7 posted 04-09-2019 11:33 PM


Regarding Rich s comment, cutting down a cup/bowed piece can often make the warp more pronounced in my experience. However, the less material there is, the easier it will be to straighten it out with screws as previously mentioned.

- tywalt

Seriously? I can’t imagine what experience you have, but you couldn’t be more wrong about this one. It’s one of the fundamental steps in stock preparation. If you have a slightly bowed 10 ft piece of 4/4 and insist on planing the entire thing flat, odds are you’ll be left with nothing. That’s why you cut it down to rough dimensions for your project before milling. You lose less that way.

I’m not talking about cutting across the bowed section, but down it. You’ll be left with pieces that are fractionally less bowed and hence more useable.

This is a lumber diagram, but the concept is the same (from Wood Magazine):

-- Knowledge is not skill. Knowledge plus ten thousand times is skill. -- Shinichi Suzuki

View Travis's profile

Travis

229 posts in 127 days


#8 posted 04-09-2019 11:40 PM



If you are making shelves to store your anvil collection that bow will flatten itself out, otherwise I m not sure what you can do. As you assemble your carcase, some of that can be pulled out with screws in the corners other wise you are stuck I m afraid.

- bondogaposis


Well crap, never should of purchased that sheet. As it happens, I already have a shelf for my anvil collection ;)
I could set the table saw on a warped shelf (that’s the heaviest thing that will go in here), assuming it would sit steady. I don’t want that thing rocking around!

-- Extra screws left over are just evidence I found a better way to put it together.

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