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While at Lowes today the attendent mentioned that 3/4" plywood is actually thinner then 3/4. I am trying to fill in a space that is 1 7/8". What size plywood/boards would you use to make up this depth?

Thanks
 

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sizes

From the net, About.com:
As with hardwood and softwood sizes, plywood sizing can be somewhat confusing. Plywood sheets usually sold as four-feet wide, but are occasionally found in two and five-foot widths. Similarly, a plywood sheet's length is commonly eight-feet, but some suppliers carry four and twelve-foot lengths. Metric sizes are also available.While the length and width of a sheet is pretty straight forward, the thickness dimensions are anything but. The most common sizes of plywood sold in the United States are 3/4", 1/2" and 1/4". However, that's not exactly correct. A 3/4" sheet of plywood is really 23/32" (and is now typically labeled as such). Similarly, 1/2" should be correctly labeled as 15/32" and 1/4" labeled as 7/32". However, everyone still refers to them as 3/4", 1/2" and 1/4".Although it doesn't seem like much, this 1/32" differential between the actual size and the common size can become an issue when working with plywood. For instance, if a woodworker is building a bookshelf where a 3/4" plywood shelf is placed into a dado cut into the shelf standards, there will be a very noticeable 1/32" gap, and the shelf will feel a bit sloppy in the dado. To combat this, the dado should be cut at 23/32" to ensure a proper fit.
:thumbsup: bill
 

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As a cabinetmaker that uses a cnc machine to process plywood, I use a lot of plywood and must accurately measure the thickness of all of it.

3/4" material from domestic mills can measure any where from .710 to .765 on occasions. The most common thickness tends to be about .730.

I don't pay as close attention to 1/2" material but i do believe the most common is about .485.

So lets play the odds and go with the most commons. 2 layers of 3/4 and one layer of 1/2 = 1.945" converted = 1 15/16"

I do use a lot of 1/4" material that is very close to 3/16". Not all is that thin though.

I think your combination will be more in lines of 2 layers of 3/4 and two layers of 1/4.

What I would do is go to the yard and measure the combined thickness of two sheets of 3/4 material in several units and do the same with the 1/2 and 1/4. When you think you have a winning combo, bring them together and measure.
Don't take any lip from the attendant either. They need you more than ever.

I hope this helps
 

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......What I would do is go to the yard and measure the combined thickness of two sheets of 3/4 material in several units and do the same with the 1/2 and 1/4. When you think you have a winning combo, bring them together and measure.
.........
That is exactly what I was going to suggest you do.
 

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I think that the plywood side of the equation has been well covered.

Just how large is the space that you have to fill?

Do you have a planer?

George
 

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Discussion Starter #6
Hi. Thanks for all the replies. I am planning on putting a 3/4" layer of plywood on the bottom of a old dresser to support the structure. I need to build up a total of 1 7/8" on the two edges so I can attach casters. The existing frame is about 1 3/4" which is narrow for the type of caster I want to use.
 

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Is the frame depth 1 7/8"?

If so, you do not need to build the bottom flush. :no: The caster's wheel radius and locking mechanism are the determining factors in full rotation. It must clear the vertical drop in the frame by about 1/8th inch or so. Set the caster in the furthermost corner and keep adding spacers between the plate and the 3/4" plywood, which you are going to add, to find the additional thickness it must be spaced down to clear the frame when rotated, maybe only another 3/4" depending......:thumbsup: bill
BTW my mobile island has a drop down skirt as well, but not as deep as your dresser.
 

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You don't need all of that build up in plywood then.

Just rip some solid stock to fill what ever space you need for the casters. The solid stock will hold the screws better anyway. Under there you can get away with using just about anything.
 

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Hi. Thanks for all the replies. I am planning on putting a 3/4" layer of plywood on the bottom of a old dresser to support the structure. I need to build up a total of 1 7/8" on the two edges so I can attach casters. The existing frame is about 1 3/4" which is narrow for the type of caster I want to use.
What structure are you trying to support? Does the dressor rack (flex), sag, or is it solid? Are you planning on supporting the weight of the dresser on the bottom dust panel or frame, or on the sides and front of the dresser? I would probably glue & screw a 3/4 x 3/4 cleat (wood strip) around the the perimeter up against the bottom frame screwing into the dresser sides, front, & back (not into the dust panel) on the underside of the dresser, then attach a 1x6 (3/4 x 5 1/2) across the cleats at each end. If necessary you could build up the thickness of the 1x6. If the sides of the dresser is made frome solid wood the cleat should only be glued in the center 4" - 6" and the holes should be slotted. Poplar or alder would be a good choice.

A picture would really help, as there is a vast difference in the way dressers are built. Also is this an old dresser, or a heirloom, or an antique? If there is a structural problem, the forums advice would quite possibly change. Hope this helps a little.:thumbsup:
 

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The Nightmare Is......

I was purchasing plywood from a plywood specialty dealer. All they stock are sheet goods.

The fork lift driver and I cut the bands on a full pallet of 3/4" plywood. The top sheet was a bit messed up in shipping so we set it aside. I took the next three sheets.

Long story short... When nothing would fit into the 23/32" dados, I measured all three sheets. The sheet where the dados had been cut, was 23/32", the other two sheets were measured at exactly 3/4" and 49/64".

In other words, the three sheets of 3/4" plywood were, 23/32", (as expected) exactly 3/4" and 1/64" over 3/4".

Recently I purchased a few sheets of real (As in from Russia) Baltic Birch. The conversation went like this.

Me, "A sheet of 1/4" BB."
Lumber Yard, "Ya know that it is really 6MM."
Me, "Yeah."

Now I used a 6MM router bit for the dados, not even close. The BB was a full 1/4" and then a smidgen.

When it comes to plywood, it is best to have a good vernier caliper.
 
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