I'm just making my first box joints - using a dado blade, cross-cut sled and
spacers (seems simpler, faster, and maybe more accurate than something like
a lynn jig).
The diagram on my Freud 8" dado (stacked) set says the main two cutter
blades together should be 1/4". I quickly found out it wasn't even close for
the box joints. Went and got my vernier caliper, measured a cut, and it was
only .230 wide.
Is this typical of the accuracy of a dado set? They get you close, and you
need to shim it from there?
TIA
Keith Carlson wrote:
> I'm just making my first box joints - using a dado blade, cross-cut sled and
> spacers (seems simpler, faster, and maybe more accurate than something like
> a lynn jig).
>
> The diagram on my Freud 8" dado (stacked) set says the main two cutter
> blades together should be 1/4". I quickly found out it wasn't even close for
> the box joints. Went and got my vernier caliper, measured a cut, and it was
> only .230 wide.
>
> Is this typical of the accuracy of a dado set? They get you close, and you
> need to shim it from there?
>
> TIA
>
>
Yep.
Measure the blade teeth. Chances are they are right at 0.125 (1/8"). The
problem is the blade steel is less than 1/8" (for cut clearance). You
probably can see that the teeth overlap a bit when you have both cutters
installed. Of course that is why they make shims. I found it is best to
keep a record of what blades and what shims are required to obtain
certain cut widths. Mark a unique identifier on each blade. Even though
each chipper blade looks the same, there may be enough difference that
mixing them up could turn a perfect fitting dado into one that is too
loose.
Another tip when using shims is to wrap your arbor with a single turn of
scotch tape. Often the shims will partially slip into one of the arbor
threads before you can get the nut on tight. This results in a different
cut width than you'd expect plus it mangles your shims 8^)
-Bruce
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"Keith Carlson" <[email protected]> wrote in message
news:cuDhd.44941$R05.22770@attbi_s53...
> Is this typical of the accuracy of a dado set? They get you close, and you
> need to shim it from there?
I don't know about all dado sets but the forrest set is designed that way on
purpose - to be a bit undersized, so you can shim out to fit your exact
requirement.
Bob
In article <cuDhd.44941$R05.22770@attbi_s53>,
Keith Carlson <[email protected]> wrote:
>I'm just making my first box joints - using a dado blade, cross-cut sled and
>spacers (seems simpler, faster, and maybe more accurate than something like
>a lynn jig).
>
>The diagram on my Freud 8" dado (stacked) set says the main two cutter
>blades together should be 1/4". I quickly found out it wasn't even close for
>the box joints. Went and got my vernier caliper, measured a cut, and it was
>only .230 wide.
>
>Is this typical of the accuracy of a dado set? They get you close, and you
>need to shim it from there?
>
>TIA
>
>
I'd rather have it as you described than have the 2 outside cutters
cut a .250" slot. If they add up to .230 as yours do, you can shim it
out to a full 1/4" if need be, but if you're cutting a groove for
undersized plywood, there is no way to reduce it from 1/4" to say
7/32"
--
Larry Wasserman Baltimore, Maryland
[email protected]
On Mon, 08 Nov 2004 10:52:08 -0700, BruceR <[email protected]> wrote:
<snip>
>Another tip when using shims is to wrap your arbor with a single turn of
>scotch tape. Often the shims will partially slip into one of the arbor
>threads before you can get the nut on tight. This results in a different
>cut width than you'd expect plus it mangles your shims 8^)
>
Another "Now, WIH didn't _I_ think of that!" moment.
I haven't noticed variations in cut width so much as the nearly impossible task
of getting the bloody things off the arbor when you go to take the dado stack
off.
THANKS!!!
Tom Veatch
Wichita, KS USA
Very normal and expected to be a tad shy of the full width listed for
the blade combo, as you can always shim to make up the shortage, but
nothing you can do if it is cutting oversize
John
On Tue, 02 Nov 2004 03:50:32 GMT, "Keith Carlson"
<[email protected]> wrote:
>I'm just making my first box joints - using a dado blade, cross-cut sled and
>spacers (seems simpler, faster, and maybe more accurate than something like
>a lynn jig).
>
>The diagram on my Freud 8" dado (stacked) set says the main two cutter
>blades together should be 1/4". I quickly found out it wasn't even close for
>the box joints. Went and got my vernier caliper, measured a cut, and it was
>only .230 wide.
>
>Is this typical of the accuracy of a dado set? They get you close, and you
>need to shim it from there?
>
>TIA
>