[jargo432]

Learned another lesson today. All plywood is not the same. Had to buy some more 1/4" plywood for my drawer bottoms. Went at it like I did the other 4 drawers and realized the new plywood was much thicker. No way would it go into the dados. After 45 minutes of sanding with 80 grit I learned lesson number 2. When you try to thin out plywood on the edge you end up with a tapered edge and it still won't fit right. I've set it aside and tomorrow I'll widen my dados to fit the plywood. (should have tested the fit on scrap first but I assumed all 1/4" plywood was the same)

Man... I could write a book called "What not to do"

 

[sawdustfactory]

Just remember these lessons so you don't repeat them ;-)

 

[rrich]

I have experienced different thicknesses of 3/4 plywood from the lift or pallet. The fork lift operator and I cut the steel bands around the pallet of plywood. The next three sheets were 23/32" (duh) 3/4" (exactly) and 49/64".

Yes, I had to recut all the dadoes.

 

[NetDoc]

So, it's best to bring a thickness gauge of some sort when you buy plywood. Good to know!

 

[Noek]

Hey Jargo, when you start making that book, I have a few chapters I would like to add

 

[bladeburner]

Instead of a lot of sanding, rout a rabbet around the edge to get it into your dado.

 

[jargo432]

Instead of a lot of sanding, rout a rabbet around the edge to get it into your dado.

Thanks, I didn't think of that!

 

[tonyuno]

Living in Canada this is always a problem, since Canada went metric the Canadian manufactured plywood us thinner than US made plywood. This also gives a problem for making dado's as most router bits are actual 3/4" .

 

[jargo432]

Living in Canada this is always a problem, since Canada went metric the Canadian manufactured plywood us thinner than US made plywood. This also gives a problem for making dado's as most router bits are actual 3/4" .

Actually that's kinda how the problem really started. When I bought my first sheet of plywood I tested it and found that my dado blades for my table saw were too wide so I used a router bit and it fit great. The router bit is exactly 1/4" and the dado blades were wider. Tonight I fixed the problem by running the already cut dados again this time through the wider table saw dados. Even after that I had to move the fence a hair and do it again but this time it fit perfect. I'll know next time to test each sheet of plywood before I put it to the cut.

 

[toolguy1000]

...... and the dado blades were wider.....

what kind of a dado blade was being used? the freud stack dado set i use is adjustable to 32nds of an inch with the provided shims. it allows for literally dialing in how wide a dado can be.

check out this brief video from the woodwhisperer about setting up a stack dado. i'd make one change to marc's technique and that's to put the workpiece and the dado stack on a piece of mdf or dead flat plywood during set up. i'm not much on resting a blade on a CI surface of a TS:

http://www.thewoodwhisperer.com/videos/setting-up-a-dado-blade/