What to expect in tablesaw flatness

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Forum topic by Madtapper posted 03-20-2011 11:08 PM 3653 views 0 times favorited 8 replies Add to Favorites Watch
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10 posts in 3448 days

03-20-2011 11:08 PM

Topic tags/keywords: table saw table flatness

Hello all:

I just purchased a new cabinet saw, and have been out in the garage/shop carefully putting everything together. My question is in reference to the flatness of the table. I have a Pinnacle 48” straight-edge, and I have evaluated the table top and both wings in all directions; all three are dead on flat in their own right. However, when the wings are attached and the straight-edge is placed across the table (side to side), there is a noticeable gap in the middle of the table. My crude feeler gauges (spark plug feelers) only go down to 0.010”, and it does not fit in the gap. However, if I use a standard piece of paper for a “feeler,” I can get two sheets in the gap if the straight-edge is placed across the entire table (side to side), and only one sheet in the gap if I am measuring only one wing and the main table. This change is consistent from front to back on both wings. I should point out that the abutting faces are all clean and true. So here are my questions…

1. Should I even worry about it?
2. Is there a relatively simple way to correct this?
3. Should I call the manufacturer on Monday?

Many thanks,

-- -- Jerry, Gig Harbor, Washington

8 replies so far

View teejk's profile


1215 posts in 3492 days

#1 posted 03-21-2011 12:01 AM

>.010 and/or a sheet of paper? what did you pay for the saw? If less then $50,000, then I think you’ll do just fine like the rest of us.

now move on to the “balancing a nickle” test.

ok…so I am being a little cynical. you are dealing with wood. even if you get your table perfectly flat, then you still have to deal with the fact that no piece of wood is perfectly flat. and then even if it is, you need a perfect angle on the blade vs the table (that big pointer on the angle might get you to within 5% of true). My point is spend more time making stuff and less time perfecting your tools if they do what you want them to do.

just my opinion

View knotscott's profile


8382 posts in 4183 days

#2 posted 03-21-2011 12:15 AM

The wings are easily shimmed level if that’s the cause of the deviation, and is a common adjustment made to new saws. But even if the wings are not the cause and the table has some deviation from flat, check your saw’s performance by evaluating the cuts….if the cuts are dead on, you’ve got no worries. Keep in mind that wood can fluctuate quite a bit over a given period of days. It’d take a fairly sizable deviation to effect the cut.

I’d be a happy camper the day my saw is the reason I’m not getting the precision I need for a project!

-- Happiness is like wetting your pants...everyone can see it, but only you can feel the warmth....

View NBeener's profile


4816 posts in 3982 days

#3 posted 03-21-2011 12:18 AM

Here’s one data point for you.

From what I understand, Powermatic has set a tolerance of .010 inches or less for flatness on its table saw tops.

I think I’d be pretty darned happy if my top was within that close to dead flat.

-- -- Neil

View NBeener's profile


4816 posts in 3982 days

#4 posted 03-21-2011 12:19 AM

Here’s another quote, from an article I just browsed:

”The end result of the casting process is then precision ground to flatness in the .0005’’ tolerance range.”

But that sounds MUCH more theoretical than it sounds like an expectation that your basic major manufacturer is likely to hit.

-- -- Neil

View patron's profile


13707 posts in 4149 days

#5 posted 03-21-2011 12:42 AM

i’ve had many tools over the years
good ones and cheap ones
i never checked any of them
unless there was something definitely wrong
in my use of them
had a brand new powermatic 8” jointer years ago
the fence was twisted
i sent it back (the fence)
and used a 4×4 post clamped to the bed
for 5 years till they sent it back – still bent !

my point is buy what you can afford

learn how it works and pay attention

if it is dangerous
or quits working
buy a better one

in today’s world
everyone wants the mercedes
at pinto prices

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

View gillyd's profile


136 posts in 3454 days

#6 posted 03-21-2011 02:16 AM

I had to shim both of my wings on my grizzly table saw, its not too bad.

View Grandpa's profile


3263 posts in 3483 days

#7 posted 03-21-2011 02:27 AM

2 sheets of notebook paper should be about .007”. So you have a space that is between .007” and .010” Part of that could be the straight edge you are using. I think I would be happy with that. You might get a flatter table but you will have to go to the mfg plant and check hundreds of them to do it. Let’s make sawdust!

View Madtapper's profile


10 posts in 3448 days

#8 posted 03-21-2011 03:06 AM

Thanks for all the input! I need to stop worrying about the small stuff! David, I find it interesting that you had trouble with a PM jointer. I purchased an 8” PM jointer approximately two years ago, and the fence was twisted. I love PN, but that purchase tested my patience! Three fences later, it is as true as can be!

-- -- Jerry, Gig Harbor, Washington

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