Actual thickness??

[Robert foster]

What is the actual thickness of plywood? I was cutting dados with my Ts that were 1/4" wide. However when I measured the ply that I was going to use with it, it was .0307" instead of 1/4". I've heard that ply is not actually the stated size. Where can one find the standard dimension or does it vary with kinds and manufacturers?

Bob

[Lee Koepke]

well, i would say not only it varies with plywood, it may even vary in the sheet.

I cut a groove for a back, and used a cutoff scrap, well, when I cut the rest of the piece, it was thinner.

Measure and then sneak up on your groove.

[Gary Keedwell]

What is the actual thickness of plywood? I was cutting dados with my Ts that were 1/4" wide. However when I measured the ply that I was going to use with it, it was .0307" instead of 1/4". I've heard that ply is not actually the stated size. Where can one find the standard dimension or does it vary with kinds and manufacturers?

Bob
.0307 ??? That is about 1/32nd of one inch. If you meant .307 that is about 1/16th" over 1/4 ". Did you mean the plywood was too big or too small:confused:

Gary

[Dan Barr]

if you are getting the digital caliper out.

the 3/4" im currently using is actually 23/32"

its best to measure first and then match your dado accordingly.

ciao,

dan

[Lance Norris]

if you are getting the digital caliper out.

the 3/4" im currently using is actually 23/32"

its best to measure first and then match your dado accordingly.

ciao,

dan

...and it sure is easier to get the correct dimension with a fractional caliper.

[Dale Lesak]

I'm making a display case for a local store. Using MDO for the painting finish. I have one sheet (4x8) that is 3/4 on one end and 5/8 on the other it's 71" long and 36" wide It fit the dado good on one end and a little sloppy (1/8"). I'll use a filler strip under the shelf and the way it's made you won't be able to see it. I measured all sheets before cutting but only measure one end. going to have to start checking both ends and sides I guess. going to have to start double checking everything before before buying.

[Robert foster]

You're right. I mistyped. I'm sure it was supposed to be 1/4" but it's bigger. Good thing I was just trying out the new dado. At first I thought I didn't do the dado correctly but I measured it with the calipers and it was 1/4 ". I wonder if the metric system would be any easier. My son has to use it all the time when he repairs the multi-million dollar machines from Germany that he maintains.

Bob

[Joe Chritz]

Most plywood is actually a metric measurement. I wish we would have switched to metric years ago.

Anyway, if the manufacturer of the sheets belongs to an organization that has standard (HPVA or APA) then it has a target thickness and is +/- some amount of that. Even with good plywood there is some variance on the thickness. MDF core removes most of the thickness variables and really good plywood is sanded before the finish veneers are put on and are nearly as good.

I think normal 1/4" ply is actually 5.5 mm which is .216" or very very close to 7/32 which happens to be the size of the cutters for rail/stile plywood conversion sets.

Joe

[Richard M. Wolfe]

The 3/4" finish plywood is actually 23/32". I use a router to cut dados fitted with that size bit that's made for use on plywood. That said, with the quality of plywood now don't take any measurement for granted......thickness, length or width. Also, I measured one 4'x8' sheet along one side from corner to corner and for both sides and it had a 1/4" difference in the measurements. For that sheet, that meant (at least on one end) the corners weren't square. More work, but I try to make a fresh cut for all edges, which also gets rid of all chips and dings. Wish I hadn't for a few things....that meant when it came out wrong I had to blame myself rather than whoever made the plywood. :o

I haven't measured 1/4" but just from looking at it there seems to be variation in thickness depending on how it's made.

[glenn bradley]

What is the actual thickness of plywood? I was cutting dados with my Ts that were 1/4" wide. However when I measured the ply that I was going to use with it, it was .0307" instead of 1/4". I've heard that ply is not actually the stated size. Where can one find the standard dimension or does it vary with kinds and manufacturers?

Bob

No standards by manufacturer that I've found. Lee has it pretty well stated. I find reasonable variation even in BB ply and other high dollar material. The "plywood" sized bits are a good idea on paper but the ply is not consistently 1/32" under or whatever. I do find the 'plywood-sized' 1/4" bit generally handy as I use it on drawer bottoms and I don't like them killer-tight anyway.

Some variation of this (http://www.sawmillcreek.org/showthread.php?t=46406) makes that frustration go away. If you don't like this version, just search around here. A few members have made some variation that fits their needs / methods. ;-)

[Norris Randall]

Which administration was it that was going to have US All go metric?
We had metric "mile" markers added to the interstate along with the regular mile markers.

There was a service station in our town that converted to metric during that time, "price per liter" and it closed after just a few months.
"Don't mess with Bubba's yard stick":D

I was in the ceramic business from '56 till ??? and during that time tile production was all over world and most machinery was metric.

The metric dimensions printed on the cartons were in small print and our old standby feet-inches was larger print. And that was usually something that was close.
(but no cigar:rolleyes:)

I think most plywood is now produced on metric equipment. So 1/4" ply still does not get a cigar.:confused: