Replies

1. 
   oldusty | Nov 05, 2008 05:50pm | #1

     wh ,

              Each different unit or run of plywood could be different in thickness as you see , it is possible low quality control from the mill as well .

        You could cut the edges that will be housed in dadoes down to say 5/8" and cut a dado to fit . The size of the plywood can be under but not over to be considered on grade .Usually the difference between a 3/4" dado and the actual thickness or thin ness of the ply is small and will not cause a problem , the ply can't really move too far . You could take a blade out and use some shims and make the dado on the tight side and simply belt sand or otherwise make the ply fit the dado .

          Why do you want to use MDO ? and are we talking about the same animal ?

          MDO , medium density overlay is usually a multi ply good core of Fir plywood with a paper backer on one or both sides and it is widely used as sign board for bill boards and such , is that what you have and want to use ?

                 dusty

1. 
   woodhacker | Nov 05, 2008 06:44pm | #2

   I'm accustomed to adjusting the stack dado set to accommodate the thickness of a piece of plywood. What's tricky is trying to accommodate differing sizes of dadoes in a single piece, for example when the shelf members to be inset into the dadoes in the side panel are of differing thicknesses. And when a panel varies in thickness from one end to the other trying to adjust the dado to fit snugly can be a real issue. A little variation is to be expected, but here I'm talking about almost an eighth of an inch variation and I feel that's excessive. But then maybe I'm just being unreasonable in my expectations. As to the material being used, what used to be called "signboard" is in fact what I'm using. Various reasons for using this material, the major reason being that this is what the customer for whom the cabinets are being built wants in the cabinets.

1. 
   oldusty | Nov 05, 2008 06:55pm | #3

      I would certainly agree an 1/8" is excessive in the same panel , the method I offered of cutting down the edges to a smaller size will allow for a tight fit and the discrepancies will be out of the dado .

       Or , take back and swap for all the same thickness panels or bite the bullet and buy from all the same unit .

         Is it just the interiors of MDO or the outsides as well ?

          Not sure if you are in business making cabinets but I have learned not to let the customer dictate the materials or any technical aspects of a job , that's why they hired you .

              dusty

2. 
   Dave45 | Nov 05, 2008 08:17pm | #4

   I've never liked the quality of plywood from a big box. Since I don't use particle board or MDF for any of my cabinets, I can't speak to their quality, but the big box plywood definitely sux. - lol

   Yes, it will cost more, but get your sheet goods from a real hardwood supply store. You'll more than save the added cost by not having to fight with the cheap stuff.

   OTOH, I have had very good luck with dimensioned hardwood at Home Depot. I can't recall the name of the supplier, but it's always been good quality and consistent.

   
   

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   Edited 11/5/2008 12:18 pm by Dave45

3. 
   DonStephan | Nov 06, 2008 03:56am | #5

   I've used a few sheets of MDO for painted outdoor surfaces, and would almost expect at least 1/16" variation in thickness along a sheet.  It's just not manufactured to that kind of tolerance.  It's going to be a nightmare for tight dado joinery.  My two cents.