Very good point! I'll have to make up a zero-clearence insert for my
regular blades.
TWS wrote:
CORRECTION! I had an error in my reply last night. My reply was based
on the assumption that you had a 'zero-clearance' insert in your saw
but I realized this morning that is probably a bad assumption and the
order of the cuts is incorrect.
Without a zero-clearance insert you should make your edge cuts first
and then the face cuts. The reason is this: on every cut you need to
have support for the work piece after the cut is made. On the face
cut this is no problem but with the edge cut you will only have 1/4
inch material left if it is the second cut. That 1/4 inch could
easily slip inside the standard insert on your saw. If you cut the
edge cut first you will have the full thickness of the board for
support throughout the entire cut.
I prefer to make the shallower cut last because it gives less of an
edge on the waste piece for the saw to grab and throw back but I also
have a zero clearance insert so 1/4 inch material is still enough to
support the work piece through the cut.
I apologize for the error.
BTW, cutting the deeper cut second increases the chance that the waste
piece will be thrown back so be sure to stand off to the left of
center as you feed the work piece.
TWS
On Tue, 16 Nov 2004 06:01:02 GMT, TWS wrote:
On Sun, 14 Nov 2004 17:50:11 -0800, Pete Martin
wrote:
On my Ryobi 10" contractor style table saw (my wife bought it!), I've
got a (cheap) dado to make it 1/4" wide. As I take the 3 1/2" wide
poplar board over it to create a (?? tenon for a rabbet?), I see the
width change even thou I holding down very hard. See below.
/
/ 3 1/2" wide
/
--------------
| 1/4" top ^ to bottom \/
---
|
| 1/2 "
|
------------
^
^
^ -- 1/4" dado
The blade is set to 1/2" at the edge of the 3/4" board. The 1/4" left
over has not been consistent. And it doesn't matter that it's a the head
or tail of the cut. I'm holding it down hard, but it's still the same. I
have to file down the pieces in order to make them fit better if not
properly. I haven't been able to figure out why that is. Suggestion??
Pete,
from your description I think you are trying to cut a rabbet which is
1/4 x 1/2". I am not sure which 1/4 inch dimension is the one you are
having trouble with (the 1/4 inch deep rabbet or the 1/4 that is left
over after you cut 1/2 deep). Since you seem to think holding down
the board harder should help I am thinking that your problem is with
the 1/4 inch left over from your 1/2 deep cut. Let me know if this
assumption is not correct.
One possibility, especially with an inexpensive saw, is that there is
backlash in the height adjustment mechanism and the depth of cut is
varying as the blade changes height slightly. Are you sure you have
locked the height adjustment? For your rabbet I would cut it with a
regular rip cut blade rather than a dado. Set your fence so that
there is 1/4 inch to the opposite side of the blade. Make sure you
measure to the tooth, not the kerf of the blade. Set your blade
height to slightly less than 1/2 inch (7/16 would be good). Lay the
board face down and cut the slot. Do all your pieces.
Next set your fence so that the fence is exactly 1/2 inch from the
opposite side of the blade and set your depth slightly less than 1/4
inch (3/16). It is best if you use a feather board to hold the work
piece against the fence, This cut will be on the edge of the board
and will cut away the waste piece. Do not stand directly behind the
board as you push it through as the waste piece might catch on the saw
and fly backward. In setting up the cuts this way you are using the
fence as the reference point for your critical dimensions rather than
relying on the blade width or height. I suggest that you get a
beginners Table Saw guide book as this will give you tips on cutting
rabbets, dados, and safety.
Let us know how this works out.
TWS
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