Table saw top not flat..

[Chad Persing]

Hey guys, I've searched and found a couple threads where someone's top had a dip in it. Well mine is high right near the front of the blade opening. I guess I had noticed something not quite right before but chalked it up to the throat plate not being set up properly. Well I am attempting to build a fence mounted tenon jig and while trying to set up the vertical support this is proving to be a real pain. Now I am just realizing how bad it is..maybe 20 thou or more. How would you go about removing material to lower this high spot? Now if this wasn't my saw i'd prolly just grab a belt sander and go to town..lol but surely there is someone who has dealt with this in a much more precise way. Thanks for suggestions!

[Eric Schmid]

I had one such table flattened by a Blanchard grinding outfit. Turned out very nicely. It was quite a few years ago, but I think it cost $150.

[Chad Persing]

Ouch..little out of my price range 😕

[Wayne Cannon]

Most communities of any size have an automotive machine shop that can grind it flat for a reasonable price, but it's been so long I wouldn't hazard a guess. You could also check with a local junior college about doing it as a project, but you would have less control over the schedule.

[Jamie Buxton]

Is the top cast iron, or something else?

[andy bessette]

Just use a belt sander to knock down the high spot.

[Matt Day]

Just use a belt sander to knock down the high spot.

That doesn't sound like a very good idea.

If you want it done right have it Blanchard ground.

What kind of saw is it?

[Darcy Warner]

That doesn't sound like a very good idea.

If you want it done right have it Blanchard ground.

What kind of saw is it?

Belt sander, some dykem, carbide scraper and a decent straight edge.

I would be afraid to grind some of these foreign castings.

[andy bessette]

"That doesn't sound like a very good idea."

To someone unfamiliar with working metal in their own shop, perhaps. Not many of us woodworkers have a Blanchard grinder. But most of us have a belt sander, which works well for re-shaping plane and chisel blades, also.

[Peter Aeschliman]

I think a sander will be okay if you carefully mark the high spot on your table and stop VERY frequently to measure your progress with a known and reliable straight edge. Be sure to measure with your straight edge in all directions- lengthwise, across the top's width, and diagonally across in both directions.

Start with finer grits first, to get a sense for how quickly material is removed. If too slow, try a lower grit.

Make sure you're in a zen-like state when you start so that you're patient. this is not something to rush.

[glenn bradley]

Since you plan to use the saw with jigs like a tenoning jig, these things become a little more critical than they would if you were framing a garage. You will have to factor in things like how long this saw is going to last you (I wouldn't spend much money fixing a contractor saw for example), can you do the tenons another way (like on the router table), if you belt sand the hump and go too far can you live with that, etc.?

A fashioned straight edge / t-bar with sandpaper attached and going at it by hand may be more doable. Make some witness marks with a felt pen and go at it for awhile to see how it goes maybe?

358192

[Matt Day]

I retract my comment then. I thought a belt sander would be too rough and would do more harm than good.

Not that I need it, but what grit do you all suggest for the OP?

[Peter Aeschliman]

I've never done it before, so I would just start with 220 and see how it goes. If too slow, move to 180 or 150. and then once general flatness is acheived, finish it off running back up the grits to 220 on a random orbit sander.

[Tom Trees]

A flap disc works well to on an angle grinder,
I would get a few permanent markers , a dead flat plate, some self adhesive sandpaper or adhesive for making your own
and marker the top, a rub for no more than three seconds should remove the marker and these will be the high spots.
finish off with lapping the top with the plate
Make sure your not making a tapered flat surface
Tom

[andy bessette]

...what grit do you all suggest for the OP?

I would do the initial shaping using 120 grit. And finish with perhaps 180, always running the sanding marks parallel to the fence.

[David Utterback]

I had PM66 done at a Cincinnati machine shop about 2 years ago for about $100 if I remember correctly. My band saw table done at the same time. It was even worse. The total for both was around $175.