Table Saw Flatness

  • Advertise with us

« back to Power Tools, Hardware and Accessories forum

Forum topic by FMG posted 09-22-2009 02:10 PM 2028 views 0 times favorited 9 replies Add to Favorites Watch
View FMG's profile


65 posts in 3275 days

09-22-2009 02:10 PM

Topic tags/keywords: question tablesaw

Hey Everyone, Slowly getting my new table saw together. I checked the main table and extension wings for flatness. The center of the right wing is .008” above the main table. Both the wings have a .006” sag at the ends. Imay have to file or shim. So my question is what is an acceptable limit for flatness?
Thank you,

-- FMG- Woodworking is 90% mental the other half is physical

9 replies so far

View knotscott's profile


8008 posts in 3370 days

#1 posted 09-22-2009 05:01 PM

You’re wood is likely to move more than 0.006” on any given day. Shimming is very common, and IMO, flatness of the top is a bit overrated unless it’s so bad it’s effecting the cuts, which can really take a big deviation depending on where the deviation is. Shim it best you can, then check your cuts….alignment is the place to get fussy.

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

View Todd A. Clippinger's profile

Todd A. Clippinger

8901 posts in 4094 days

#2 posted 09-22-2009 05:15 PM

I am with Knotscott. I have never checked my table to the degree that a machinist would.

I flushed the wings. I put a basic straightedge across the top and it looked good. I did not use feeler gauges and micrometers.

The tablesaw cuts good, my joints are tight, my work is great.

Woodworking will drive you crazy if you approach it with a machinist’s mentality. Wood moves all over the place.

-- Todd A. Clippinger, Montana,

View sandhill's profile


2128 posts in 3918 days

#3 posted 09-22-2009 06:15 PM

Same thought here, The reference will be 90 degrees to the blade and the wood will span any voids right?

View GMman's profile


3902 posts in 3692 days

#4 posted 09-22-2009 06:24 PM

Knotscott and Todd are 100% right your working with wood your not building a space ship. lol

Don’t try to be too accurate it a waste of time wood moves.

View FMG's profile


65 posts in 3275 days

#5 posted 09-22-2009 06:50 PM

Thanks fellas, sounds like all very practical advice and makes alot of sense. I was kinda going by what i read in reviews and have seen that this is one of the tests. Thanks for saving me some trouble.

-- FMG- Woodworking is 90% mental the other half is physical

View Kent Shepherd's profile

Kent Shepherd

2718 posts in 3281 days

#6 posted 09-23-2009 05:07 PM

There is definitely a time to be anal about machine set up, this is not one of them. I agree with everyone else, as this is a waste of time.


View patron's profile


13603 posts in 3335 days

#7 posted 09-23-2009 05:13 PM

you buy the tools you can afford ,
you learn with them the best you can ,
you buy better ones if they quit working for you .
nothing is as it seems ,
the only constant ,
is what are you going to do next ?

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

View coloradoclimber's profile


548 posts in 4062 days

#8 posted 09-23-2009 05:49 PM


Here’s a similar thread from about a year ago.

0.008 is probably well within the manufacturers spec and sounds flat enough to do excellent woodworking. Worrying about getting it flatter than that is probably a crap shoot.

As for the wing sag you might try to correct that. Since shimming to eliminate the sag is cheap and easy it’s probably worth a try. A strip of tape on the bottom side of the joint where the wing attaches to the table would probably be enough to lift the wing ends. Loosen the wing, slide the strip of tape in at the bottom, maybe a quarter or half inch wide piece of tape or paper or any other thin shim, tighten the wing back up.

View 45acpbuilder's profile


49 posts in 3207 days

#9 posted 09-24-2009 10:56 AM

I agree with everyone – your .008 “mountain” in the wing isn’t an isue. Getting the sage out is a good, essential, idea though. I use the aluminum “flue tape” sold through HVAC suppliers. It won’t compress over time as much as masking or other tape. It’s relatively cheap, .003 or .004 thick and makes excellent shim stock for just about everything you can think of. It’s adhesive is also robust so it won’t come off in the future. I’ve used it to seal the joints in my DC pumbing. I didn’t glue them in case I reconfigure things in the future.

-- M1911BLDR

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics