I'm making a closet organizer for SWMBO. Ya know, to score points, so I
can buy more tools. 8-)
I picked up some BB plywood for this project. Assembly involves a few
dados. I found that the BB does have a little variation in thickness, so
the dados needed some tuning. I used a card scraper for this, and after
I figured out how to attack the side wall of the dado properly, it
worked OK, but to took a long time. I found that I needed to refresh the
edge on the scraper pretty often.
What alternatives are there? Would a side rabbet plane work OK in
Instead of making dados to fit the full thickness of the plywood, consider
making narrower dados and then rabbet the ends of the plywood to fit them. A
1/8 rabbet off each side will leave a 1/2" for strength and should eliminate
the surface thickness variations that are affecting your dado joint ( a good
fitting 1/2" dado is better than a 3/4" poorly fitting dado). Better
quality plywood like birch cabinet ply may cost a little more, but the
thickness tolerances are much tighter, and therefore are easier to cut good
fitting dados for.
"Art Greenberg" < firstname.lastname@example.org> wrote in message
On Tue, 27 Mar 2007 12:07:43 -0500, Charley wrote:
I am having trouble seeing how this would get around variations in
thickness. I think any method of making the rabbet that references the
surface of the plywood would just transfer that variation to the
I did say I used BB (baltic birch). Are there grades of that material,
or sources, that have better thickness tolerance?
Basically, he's saying trim the board instead of the dado to fit. Its not
all that easy to reliably trim a little strip (3/16" wide strip) next to the
edge of a board. A straight board guide clamped to the shelf and a rabbet
plane work pretty well.
For trimming a dado after the fact, the side rabbet plane set by Nielson
seems pretty nifty, though not much use for anything else.
I like the approach of cutting the dados the right width in the first place.
This means precutting the shelves to know what thickness is required. Then
you have to play games with dado blade setup on the tablesaw or use of a
router with an adjustable dado jig.
I am very surprised you got inconsistent width boards in BB plywood. I've
found it to be very, very consistent in thickness and quality.
Right. I wonder how well those planes will work in plywood, where its
cutting with the grain in some of the veneers, across the grain in the
I thought that should have been the case, and that is exactly why I
bought a number of sheets of the stuff to keep for projects like this
I dealt with my local lumber yard, which had to special order it.
They're much more accustomed to dealing with construction lumber, and I
was dismayed to see that they treated the BB just like construction
lumber - just thrown into the truck as if it were underlayment or
sheathing. An experiment that seems to have failed. It may be necessary
for me to rent a truck and drive a bit to get decent product.
> The 5x5 5 ply can be Russian stuff, too. Not as good as the Finnish.
> Usually has a violet stamp on it with Cyrillic FKA (factory) and a
SFWIW, my landlord uses Birch ply to fabricate tooling to stamp gaskets.
Absolutely refuses to use Russian material.
Art- if usnig a saw to cut your dadoes, an adjustable dado cutter head
should do the trick. Get it honed in on a piece of scrap them hit
If you are using a router, they make bits purposely undersized to
route the dado to be the same thickness as the plywood.
You shouldn't have to scratch off the edges of a dado no matter what
you are using to cut.
On 27 Mar 2007 11:09:09 -0700, email@example.com wrote:
I used both a router with a jig, and a tablesaw with dado set and shims.
I fussed with both using a sample piece. The problem is, the sample
turned out to not be wholly representative of the batch of plywood I
had to work with.
If only that were true. I bought a bunch of Baltic Birch thinking it
would be consistent enough in thickness to make it so. I guess, even
with BB, I'll have to hand pick each piece using a dial caliper.
Art Greenberg wrote:
> I picked up some BB plywood for this project. Assembly involves a few
> dados. I found that the BB does have a little variation in
> the dados needed some tuning.
Take your choice, stacked dado on a T/S or a router.
Make dado in two (2) passes with an undersize cutter.
PITA, but it solves the problem, just keep your dial caliper and
marking chalk handy.
On Tue, 27 Mar 2007 19:01:48 GMT, Lew Hodgett wrote:
PITA is an understatement.
I don't see how to control the TS with the accuracy needed to do it this
way, without one of the really cool positioner-based fences from
Jointech or Incra.
Certainly doable with a simple router jig that is adjusted using the
shelf as a gauge. I have a gadget from Woodline that works that way
(DadoWiz), and that's what I used for most of the dados. But I did _not_
anticipate the need to reset it for each end of each shelf.
I suppose I could go back and re-cut each dado this way, that would take
care of the problem. But it seems so much easier to neander it with the
Live and learn.
Art Greenberg wrote:
> PITA is an understatement.
> I don't see how to control the TS with the accuracy needed to do it
> way, without one of the really cool positioner-based fences from
> Jointech or Incra.
A UniFence will do the job; however, there is a way using both T/S and
First pass use T/S with undersize dado, then clean up to size with
router and a straight edge.
Just make sure you use a common reference for all cuts, either top or
bottom of T/S dado cut.
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