power tool table flatness, what to expect

[Andrew Howe]

All,
Say you were buying a new power tool and it has a 20" x 18" cast iron table. What would you expect for flatness?
No more than 0.001" deviation ?
Opinions needed

[Jim Neeley]

First, you don't saw what the power tool is so there's no way to answer in terms of functionality.

Second, you don't saw whether you're buying a high-quality (made in US, Canada, Germany or or other quality-oriented site or with heavy manufacturer inspection/quality control oversight) or a 4th world quality tool (let the buyer beware; we're going to make it as cheaply as you will buy to maximize our profits; you don't hold us to it - silly you) manufacturer.

Also, if it was a router table you could probably get by with 0.01.. if it was a cast iron flatness reference surface you might need another decimal place or two. My new-style unisaw table is about twice that wide x 3 times that long and is flat to < 0.0005" over its full surface as measured by a Starrett master straightedge.

I canot speak as to whether or not this is typical.

Jim
.

[Ken Fitzgerald]

It depends on what the manufacturer's specifications are. It should meet that specification.

It's also important to realize if you are working with wood, it is a dynamic material much more so than most metals and some plastics. Wood will move with changes is humidity, temperature and as a relief to internal stress.

[Ty Williams]

Geeze, and I'm happy with my 1954 Craftsman Model 100 table saw that's flat to within 0.1"! Worst part is that the table is arched up (convex) and both wings are arched down (concave), so the table and wings are only coplanar at two points :lol:


Still cuts wood, still is more precise and accurate than I can see. If the limitation is my eyes, the table is flat enough.

[scott spencer]

As long as the top of the tool doesn't effect the cut, I'm okay with it, and don't measure it for deviation.

[Richard Wagner]

Some how I doubt that, Jim. That is pretty flat. If it is really that flat, you paid for it and it doesn't do a thing for you except give you a good flat glue table.

[Prashun Patel]

What kind of tool is it?

I'd expect to get what I pay for, but I'd only return it if the quality of the output suffered. I'd be most critical of a router table, then tablesaw, then bandsaw, then drill press.

[glenn bradley]

As others have stated, depends what the tool is. A sander should be "close" but, deviations in grit and resin bond make super-critical alignment questionable. I believe my old Orion ZipCode saw spec was .007" over the surface and they sent me a new top when the first was .013". This dip was right at the blade throat and so, in their opinion, impactive to accurate setup. I use my jointer to bevel parts so the fence is fairly critical to me. Other people edge-joint particle board and don't care.

[Jeff Duncan]

Well to be honest I have several thousand pounds of machinery sitting in the shop and with the exception of the jointer, have yet to measure the flatness of a table? Is there a reason your worried about flatness? As the others have said there's a LOT of different variables here that haven't been covered. Need to provide more info for a good answer.

JeffD

[Keith Hankins]

For warrantee purposes less than .003/sq ft. is considered acceptatble my most mfg's. I know I checked prior to purchasing a big TS. I have some big pieces and none are perfect. It really depends on where its at a few thou won't make a diff its wood. Now if I were machining metal might be diff. Never had an issue.