Planing Plywood

[EricSchimel]

Has anyone ever tried using a bit table surfacer bit to shave a few thousandths off of plywood? I've got a bunch of Baltic Birch that varies a little bit in thickness. I'm going to make a bunch of CNC cut furniture and it would be really nice if every sheet was the same thickness.

I thought that I might be able to use the table surfacer to shave down each side of the "thicker" plywood, maybe .02 or .03 total. Has anyone tried this? I'm worried about making the plywood fold up like a taco...

[Kyle Stapleton]

I would just cut them and sand the joints that are tight.

[EricSchimel]

I tried that on the first one and it didn't go well. Plus, I want to deliver these tables to kids and students ready to be slotted and bolted together.

You can see pictures here:

www.makertable.com (http://www.makertable.com)

[jTr]

Sounds like a great idea- real question is: do you have enough veneer thickness to truly "true" those faces? With Baltic Birch, perhaps. I have a similar situation - making flat puzzle joints for upholstery sub-frames. I picked Aruoco ply, as it has close to 1/8" face veneer thickness. This way, I'll do the joinery, run through wide belt and have a true, clean surface. Problem for you is the Aruoco will not likely look as good as the Baltic. I would say best if you can find someone with a super-wide sander locally, though a 50" is very rare, and if you're using 60x60 Baltic Birch, game over.

Let us know how that works out- you're still going to want to sand, as the surfacer will leave lap marks that you're probably not going to be 100% pleased with.

jeff

[EricSchimel]

I am pretty certain I'll have enough veneer on both sides to not get into any glue. I agree about the wide belt sander. Those are hard to find, and you have to pay someone to use them! :). I'm trying to use my ShopBot for everything in the shop.

I know if I table surface it I will have to hand sand the faces and I'm OK with that, I already have to before I finish the stuff anyway. The real reason I am considering this is to have less waste... Those tables in the link above were made on two sheets, each with different thickness. It worked because I strategically places the parts, and adjusted the width of my slots accordingly. I am going to be running up to 10 of those tables at once, and being able to have all parts work with all of the tables would make less waste, and easier milling.

I suppose I should just try it with some scrap and see what happens...

[coryatjohn]

Do you have a vacuum hold down system for your table? If so, then I would say it should work just fine. You might want to use a smaller bit than what you use for table resurfacing, if for no other reason, to keep the tool marks to a minimum. Another tip I would add is to not use the table surfacing program. That goes against the grain at times. Instead, use a pocket toolpath with a raster in the direction of the grain to avoid those cross grain cuts. Don't use a finish pass and instead overlap the ends of the sheet to eliminate the cross grain cuts.

I use my SB as a planer all the time. It works great.

[Ajcoholic]

Has anyone ever tried using a bit table surfacer bit to shave a few thousandths off of plywood? I've got a bunch of Baltic Birch that varies a little bit in thickness. I'm going to make a bunch of CNC cut furniture and it would be really nice if every sheet was the same thickness.

I thought that I might be able to use the table surfacer to shave down each side of the "thicker" plywood, maybe .02 or .03 total. Has anyone tried this? I'm worried about making the plywood fold up like a taco...

Taking 20 or 30 thousandths off the plywood will leave you with next to nothing of the face veneer left.

Perhaps a better brand or grade of plywood would be a better solution? I use a fair amount of sheet goods and most of the stuff I get is within 5 thousandths across a whole lift. It's all domestic stuff and not cheap. But you get what you pay for.

I don't think this is the proper way to tackle the issue. Especially if you remove from one side which will give an imbalanced panel prone to warping.

[EricSchimel]

The last batch of Baltic Birch I got was anywhere from .710 to .725 thick. Other than the the wood was fantastic. Very flat and nearly void free. I am open to using different material if anyone has experience with something that is more regular....

If I did "shave" it I'd try to split the amount I need to take off and do the same on both sides...

[bill.young]

Plywood is a struggle, that's for sure.

Does the whole part need to be a consistent thickness or just the joints? If it's just the joints then can you just machine them to a specific thickness, zeroing at the table so you know how thick they'll end up? Would save a lot of surfacing and the machined face will be hidden with the joint. I do this a lot with tenons when I need a good fit, cutting them to a precise thickness so that they fit their mortises just right. It's a pain, but not a major one.

[EricSchimel]

That's pretty damn brilliant. I'm already zeroing to the table so I think this could just work. I still need to be careful because I am using threaded inserts to bolt this table together, and if I was off too much, it could throw my bolt holes off.

This could be a dynamite way to get stuff to work that was just a little out to work.

No wonder you're a "Super Moderator" ;)

[markevans]

I had a project that called for 3/8",all I had was 1/2", it milled down no problem. I love bb, just wish it was available for local pickup.

[myxpykalix]

Eric,
"No wonder you're a "Super Moderator"
This is true but we rarely see him in his T shirt with the big S on the front!