Best way to flatten a large table top

[Maurice Arney]

I just finished making a large cherry top for a dining room table (44" X 86"). In the past, being fairly new and not having a vast array of tools at my disposal, I have used my belt sander to clean up table tops. I "float" the sander diagonally back and forth until the top looks clean then use an orbital sander and finally hand sanding the entire top to finish. This approach has worked but it does tend to leave highs and lows in places (not enough to see but you can feel them). So now I have a little money to spend and looking for some new tools and/or methods. Should I be looking at a "fore plane?" a "jointer plane?" or maybe just a #4 or #5 smoother? Or what other method(s) or tools would you use to flatten a table top this large?

Right now I have two planes: A Stanley low angle jack, and a Stanley #4 smooth.

I would really like an excuse to buy a new plane :)

Thanks

[Steve Friedman]

That's a big top to flatten by hand, but if you wanted to do it, you need the longest plane you can get (#8 or wooden jointer). If it's really out of flat, the initial work might be quicker with a #5 or #6 with a cambered blade. The truth is that for flattening something that big, the best (affordable) solution may be a router sled with a tailed router. Using a hand plane to reach across a 44" wide plank will be a challenge.

By the way, what are you using as a straightedge to test the flatness along the length? Also, did you make winding sticks that wider than 44" to check the wind in the board?

Sounds like a cool project.

Steve

[Maurice Arney]

That's a big top to flatten by hand, but if you wanted to do it, you need the longest plane you can get (#8 or wooden jointer). If it's really out of flat, the initial work might be quicker with a #5 or #6 with a cambered blade. The truth is that for flattening something that big, the best (affordable) solution may be a router sled with a tailed router. Using a hand plane to reach across a 44" wide plank will be a challenge.

By the way, what are you using as a straightedge to test the flatness along the length? Also, did you make winding sticks that wider than 44" to check the wind in the board?

Sounds like a cool project.

Steve

Thanks Steve, Maybe I'm using the wrong words to describe what I'm doing. It doesn't really need to be flattened in the sense that it's twisted or warped in any way. Maybe I should have said is "cleaned up" and "smoothed." Although the winding stick thing is a great suggestion (I had not heard of them until now ;P). I will make some winding sticks to see how "flat" it is. Mostly what I have is glue that has squeezed out during clamping as well as slight imperfections in the stock surface. Perhaps I should focus more on cleaning up the glue joints while they are still wet. I've seen the router sled method and have been wanting to try it. But I think I'll save that for a rough project like a work bench rather than practice on my cherry table. Like I said, there are some very minor highs and lows but you can't see them. Maybe I'm just being too fussy.

[Stephen Cherry]

I'm hoping that you got the boards smoother before your glue up, and just need to work on the glue lines. I've put myself in the position that the boards in the glue up on a table top was not aligned very well, and it took forever to get it smoothed out. In clamping a table top, the thing to remember is that most of the work is in the clamps and cawls that hold the table flat. The together part is easy, so it's the secondary factor. So you have two sets of clamps- one set, with cawls, for flat, and another set for together. I think that everyone learns this the hard way.
http://www.finewoodworking.com/item/35878/clamping-cauls-the-secret-to-great-glue-ups


One thing about cherry is that if it has grain patterns that reverse, the wood will want to tear out. A high angle plane works better for this. I have a primus hand plane that works better for this than my LN no 4. And a Stanley plan is about as good as the LN. A card scraper is even better than both.

If you have some real misalignment, you may be better off trying to find a friendly shop with a big wide belt sander. Or if you have the width to work with, or extra lumber, if the misalignment is pretty bad, I would not hesitate to rip the whole thing down with a good dedicated rip blade, and very carefully regluing using the techniques in the article. Also, it is OK to do the glue up in sections. You do not need to glue the whole top in one shot.

Edit- read the second post that was entered while typing. For glue, you need a card scraper. Much better than a plane for this. Keep it sharp though. As for winding sticks and overall flatness, remember that the table aprons job is to keep the top flat. Any top would like to turn into a potato chip, the apron keeps it from doing this.

[Howard Acheson]

In my shop, the way we would flatten a large surface is to use a long steel or aluminum straightedge. Run it over the surface in a number of different directions. Using a pencil and make "squiggly" marks on the high spots. Using a belt sander, sand down the high spots. Sand in the diagonal direction. Again, using the straightedge, check and mark for any high spots. Carefully flatten the high spots and check again.

Once you have it flat change to 100 grit paper on your belt sander and carefully sand. Keep checking for flatness and move up to 120 grit. Next use a 1/2 sheet orbital sander with 150 grit then 180 grit. Finish by sanding buy hand with 180 grit paper on a flat, felt covered sanding block.

Using the above one should be able to get a flat surface with 15 to 30 minutes work.

[Michael Koons]

Maurice, I built 5 maple countertops last year. They ranged from 50" to 80" long and were all 30" wide. They were made of 1.5" wide pieces of maple glued together. I did exactly what Howard describes above. Took a straightedge, marked the high points with pencil.

Instead of a sander, I took my #6 plane (18" long) and attacked the surface with it. Once I knocked down the high spots, I took the straight edge and a feeler gauge to check my progress. After they were flat to a few 1/1000th's of an inch or so, I took my #4 plane to clean up the surface. A lot of elbow grease and sweat but I was very happy with my results in the end.

[Jim Matthews]

A bigger plane with a dull blade will produce a lesser surface than a smoother with a sharp blade.

If you buy another of the current Stanley offerings, it will have a stock blade of the same quality.
Have a good look at how sharp your current tools are, today.

Your current smoother - with a properly set up blade, cap iron and lever cap will probably do just fine.

[Maurice Arney]

I'm hoping that you got the boards smoother before your glue up, and just need to work on the glue lines. I've put myself in the position that the boards in the glue up on a table top was not aligned very well, and it took forever to get it smoothed out. In clamping a table top, the thing to remember is that most of the work is in the clamps and cawls that hold the table flat. The together part is easy, so it's the secondary factor. So you have two sets of clamps- one set, with cawls, for flat, and another set for together. I think that everyone learns this the hard way.
http://www.finewoodworking.com/item/35878/clamping-cauls-the-secret-to-great-glue-ups


One thing about cherry is that if it has grain patterns that reverse, the wood will want to tear out. A high angle plane works better for this. I have a primus hand plane that works better for this than my LN no 4. And a Stanley plan is about as good as the LN. A card scraper is even better than both.

If you have some real misalignment, you may be better off trying to find a friendly shop with a big wide belt sander. Or if you have the width to work with, or extra lumber, if the misalignment is pretty bad, I would not hesitate to rip the whole thing down with a good dedicated rip blade, and very carefully regluing using the techniques in the article. Also, it is OK to do the glue up in sections. You do not need to glue the whole top in one shot.

Edit- read the second post that was entered while typing. For glue, you need a card scraper. Much better than a plane for this. Keep it sharp though. As for winding sticks and overall flatness, remember that the table aprons job is to keep the top flat. Any top would like to turn into a potato chip, the apron keeps it from doing this.

Yes Stephen I ran them through my jointer and they fit together nicely with no gaps. I always use cauls to flatten but no matter how careful I am, I always have spots where the glued edges don't quite line up. I sometimes use biscuits on problem areas but those don't assure perfect alignment either. So I always end up having to flatten... Not flatten the piece but flatten the surface of the piece. Per your suggestion, I just ordered some card scrapers as well as a cabinet scraper for the glue clean up.

[Stephen Cherry]

Yes Stephen I ran them through my jointer and they fit together nicely with no gaps. I always use cauls to flatten but no matter how careful I am, I always have spots where the glued edges don't quite line up. I sometimes use biscuits on problem areas but those don't assure perfect alignment either. So I always end up having to flatten... Not flatten the piece but flatten the surface of the piece. Per your suggestion, I just ordered some card scrapers as well as a cabinet scraper for the glue clean up.

Maurice- everyone has been through this. The bigger the table, the more time I will spend getting everything super aligned, even using a mallet on the back to knock everything into plane after the clamps are on, but not super tight. It's a lot easier to tap things into plane while it can still be done. Then once you are satisfied and have let things dry for a while, scrape the glue off before it turns rock hard.

[Tom Scott]

Maurice, I just went through this with a table top almost the same as yours - 9' x 42".
Like you I was careful with the glue up, but there are always irregularities. The size of plane you need depends on how bad it is to start with and how flat you want to make it. If it is only minor cleanup, then a #4 smoother would be fine. Or, minor work with the LA Jack and then smoother. If it needs more work or you're going for really flat, then you need to jump up to a #7 or #8 jointer plane. I took this route...a lot of work on a piece this size, but I've waited a long time to build this table.

[Jacob Reverb]

I would use a jack plane or smoothing plane. These will get the table flat enough to "look" planar, which to me is good enough.

If you use a jointing plane, you will get it a lot closer to "planar" but you will have to do a LOT more work (and remove a LOT more wood) to do so, with no measurable benefits to the eye. In other words, it won't LOOK any flatter, but you can bask in the knowledge that it IS marginally flatter, and only took an additional 300 hours of work to get that way!

[Myk Rian]

I've seen the router sled method and have been wanting to try it. But I think I'll save that for a rough project like a work bench rather than practice on my cherry table.
It does work, but you need a large area for the sled. I just built one for my table saw to flatten a redwood burl. 60 or 80 grit in my ROS took care of the lines easily.

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