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Bob Davis
 
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Default Jet table saw table out of tolerance

I purchased a new Jet "Supersaw" complete with 52 inch rail, table
extension, and sliding table about a month ago. One of the primary
attractions of this saw was the sliding table. I've never felt it worked as
well as expected. Though its heavy and slides smoothly, it did not seem to
line up with the blade properly. When I did a cross cut, the blade would cut
deeper into the wood, as it moved into the rear teeth of the blade. This is
a symptom of the table not sliding parallel to the blade. I had already had
the dealer check blade alignment with the right side miter slot and it was
dead on. The sliding table alignment is pretty idiot proof. They give you
some .020 shim stock to place between the sliding table and the main saw
table. You just butt the two together and tighten up four bolts. If the left
side of the main saw table is parallel with the saw blade, the sliding table
should move parallel.

Well, that last statement is a big assumption. I adjusted and tweaked and
measured until I was blue in the face. Then I decided to check what I
assumed was ok - the left edge of the main saw table. Boy was I in for a
shock. I almost purchased a dial guage and fancy clamp just to accurately
measure how closely things were aligned. But then I thought - "This is
silly". Instead of that, I bought set of good ol' feeler guages and used my
combination square. I discovered the sliding table was about 0.029"
difference between the front and back side of the blade! Jet's maximum
tolerance is 0.0118" for blade parallelism. I have not gone back to Jet
technical service yet. They told me that this was a simple tuning problem
and walked me through the procedure for aligning things (the ol' mark the
saw tooth and measure against the same tooth front and rear).

I'm convinced that this is a manufacturing defect. Its as if the left side
of the table never received a final machining. I did some gross
measurements using a combination square and took some pictures to illustrate
the problem. Admittedly, you cannot measure thousandth's of an inch with a
cheap combination square, but it does hold a constant measurement when
locked and relative measurement is what we are interested in. My pictures
are at http://www.anneldavis.com/bobandanne/table%20saw.htm. If you have
the patience to look these over, I'd appreciate any comments about my
assessment.

Bob


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Leon
 
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Default Jet table saw table out of tolerance

Bob, I would get back with Jet. BUT, you may want to reread what you have
written here and perhaps rephrase what your problem is. You are apparently
not using the right descriptions to describe the problem. You indicate that
the blade cuts deeper into the wood when you cross cut and push the wood
into the rear teeth of the wood. A blade is round and probably cannot cut
deeper into the wood at the back teeth. Perhaps you meant to say that the
blade cuts wider at the back of the blade....I guess. It seems to me that
if the blade is actually dead on parallel to the miter slot and the left
side of the table is not parallel to the blade, you would need to put shims
between the left side of the table and the slider setup, either at the front
or rear to bring the slide path parallel to the blade.


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Bob Davis
 
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Default Jet table saw table out of tolerance

Leon,

Thanks for the critique. Yes, the choice of "deep" is not the right word,
as this is normally associated with "depth of cut". What I meant to say was
that the rear teeth cut further to left of the front teeth, instead of
following same kerf cut by the front teeth.

Your analysis of getting things parallel is correct, except for how its
done. The sliding table moves, so you don't shim it, like you would the
right-side wing. You have to re-align the stationary part on which the
sliding part runs. Jet provides adjustments to do this. However, I don't
think they ever envisioned having to adjust the front to back more than a
few thousandths of an inch. I've already moved the rear of the sliding
table to the left 0.080 " and its still not lined up. I had to really force
it to get that much adjustment out of it.

What gets me is that if I had bought the table without the sliding table or
ever decided to revert to a fixed left wing, there is no way that a left
side miter slot could be lined up without re-machining the left side of the
main table.

I'm calling Jet back this morning and ask them what they recommend doing
about it and if I should be concerned.

Bob


"Leon" wrote in message
. ..
Bob, I would get back with Jet. BUT, you may want to reread what you have
written here and perhaps rephrase what your problem is. You are

apparently
not using the right descriptions to describe the problem. You indicate

that
the blade cuts deeper into the wood when you cross cut and push the wood
into the rear teeth of the wood. A blade is round and probably cannot cut
deeper into the wood at the back teeth. Perhaps you meant to say that the
blade cuts wider at the back of the blade....I guess. It seems to me that
if the blade is actually dead on parallel to the miter slot and the left
side of the table is not parallel to the blade, you would need to put

shims
between the left side of the table and the slider setup, either at the

front
or rear to bring the slide path parallel to the blade.




  #4   Report Post  
Bob Davis
 
Posts: n/a
Default Jet table saw table out of tolerance

FOLLOWUP:

This story has an extraordinarily happy ending. I sent the pictures I made,
along with some drawings to explain the problem to Jet technical support via
email. This was really tough to explain in words, but the pictures really
helped. Two hours later, the technical support rep called and said my
pictures and explanation were very good and showed a manufacturing defect.

Their solution: THEY WILL REPLACE THE WHOLE SAW! They will contact my local
dealer and arrange the whole thing.

Jet has just created an incredibly loyal customer. I've called their
support 4-5 times in the last month and I've found it to be excellent. I
can't say enough good things about them.

Bob

"Bob Davis" wrote in message
ink.net...
I purchased a new Jet "Supersaw" complete with 52 inch rail, table
extension, and sliding table about a month ago. One of the primary
attractions of this saw was the sliding table. I've never felt it worked

as
well as expected. Though its heavy and slides smoothly, it did not seem to
line up with the blade properly. When I did a cross cut, the blade would

cut
deeper into the wood, as it moved into the rear teeth of the blade. This

is
a symptom of the table not sliding parallel to the blade. I had already

had
the dealer check blade alignment with the right side miter slot and it was
dead on. The sliding table alignment is pretty idiot proof. They give you
some .020 shim stock to place between the sliding table and the main saw
table. You just butt the two together and tighten up four bolts. If the

left
side of the main saw table is parallel with the saw blade, the sliding

table
should move parallel.

Well, that last statement is a big assumption. I adjusted and tweaked and
measured until I was blue in the face. Then I decided to check what I
assumed was ok - the left edge of the main saw table. Boy was I in for a
shock. I almost purchased a dial guage and fancy clamp just to accurately
measure how closely things were aligned. But then I thought - "This is
silly". Instead of that, I bought set of good ol' feeler guages and used

my
combination square. I discovered the sliding table was about 0.029"
difference between the front and back side of the blade! Jet's maximum
tolerance is 0.0118" for blade parallelism. I have not gone back to Jet
technical service yet. They told me that this was a simple tuning problem
and walked me through the procedure for aligning things (the ol' mark the
saw tooth and measure against the same tooth front and rear).

I'm convinced that this is a manufacturing defect. Its as if the left side
of the table never received a final machining. I did some gross
measurements using a combination square and took some pictures to

illustrate
the problem. Admittedly, you cannot measure thousandth's of an inch with

a
cheap combination square, but it does hold a constant measurement when
locked and relative measurement is what we are interested in. My pictures
are at http://www.anneldavis.com/bobandanne/table%20saw.htm. If you have
the patience to look these over, I'd appreciate any comments about my
assessment.

Bob




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