Thread: Flat table tops

There are a number of ways, but for a large table top, unless you have an industrial sized workshop at your disposal, the best way to do it would almost certainly be with a hand plane.

That said, unless you've use planes in the past, it is a skill which should be practiced and somewhat refined before applying it to a table top. There is a lot of information about flattening panels on the web, and a lot of different methods and dogma associated with it. There are many ways to skin this particular cat with planes (which sounds horrible for the cat...) but most will start with a plane that is the equivalent length of a Stanley #5, #5 1/2, or #6 and end with something the equivalent of a Stanley #7 or #8 before either sanding, scraping, or smoothing with a Stanley #4 or # 4 1/2 to achieve a finish ready surface.

However, that's just a general answer, not specific to your task.

Can you elaborate a bit more on the dimensions of the table top and possibly provide some photos? The more information we can get on a specific project the more we can help.

Cheers,
Luke

Thanks Luke. I'm referring to tables I made in the past, up to about 3'6" x 5'. The tops did not come out as flat as, say, a piece of MDF. Problems I've had with hand planes arose in getting an even thickness, and around hard knots and burrs. Sharpness, I know, is essential, and a good set. Sometimes though, a straightedge shows a small depression in the surface that would involve planing all of the rest of the surface around it down to that minimum thickness. Daunting!

I've had better success jointing up thicknessed planks as near perfectly as possible, then avoiding the hand plane and just trying to remove the ripples with a cabinet scraper. It's hard work, as you no doubt know, plus, if the scraper is nicely sharp, you can easily end up scraping unevenly and spoiling the flatness. Ideally, I would use a straight scraper as wide as the table but operating it would require some extra muscles, maybe a horse! I wonder what the professionals use. Is it a wide-belt linisher?

I'm also interested in how people join up planks to avoid the development of depressions later, e.g. when the rings straighten as they tend to do. Must the planks be quarter sawn? The grain may then be a bit uniform and dull. Or, if slab sawn, should the planks be glued with alternate faces up so that one warps upwards while its neighbour warps down to counteract it, one hopes. The problem with that is that it can split up the grain patterns across a log.

Making a table nicely is such a good way for people to enjoy a pretty piece of wood. Thanks again Luke, and to anyone else who is thinking of contributing. "Sometimes the smallest piece of advice can have the biggest result."
All the best, John

My guess would be that the pros use a wide drum sander. They make them in widths of several feet, and as long as you support the bottom and take small bites, you can flatten a top and then flip it over and flatten the bottom to be parallel. I suppose an extremely wide jointer and planer would do it as well, but I don't know if they make those machines in 3' widths. It'd be quite a thing to see...

As far as the plane tracks, there are ways around it. The most common is a slight camber on the iron, but you can also do it by dubbing back the edges of your plane iron so that the bevel rounds back ever so slightly at the corners. I prefer the second way to the first because I find it easier to control.

Regarding uniform thickness, if you use a marking gauge to mark the least thickness around the edge of the table and then carefully hand plane the thicker parts to meet that line, you should be able to get it within a mil or so at the edges, and no one will notice the difference on the bottom edge of a 3' x 5' table. Again, this requires getting used to a hand plane and I don't mean to imply it's child's play, but as long as you don't get overzealous and just carelessly lose track of where you are, it's very doable. Also, if it's the bottom side, it doesn't really matter if the middle is slightly (a mil or less) thicker or thinner than the edges.

There is a place in Brisbane called "Wood 'n You" that is nothing more than a big workshop with "larger than hobby scale" machinery for hire. You pay on an hourly basis. There is likely a place like that in Melbourne somewhere, or at the very least a cabinetmaker's shop that will let you use theirs (or do it for you) at a modest price. You may even be able to call Wood 'n You and ask them if they know of a place in Melbourne.

To give you an Idea of price, I went in there and jointed and thicknessed two large slabs on their 22" combo machine, then used their large, sliding table saw to rip the natural edge off of them, and it was $75.

Hope that helps,
Luke

As a 'pro', I can say that the most crucial part is when you're joining the boards together. Obviously they need to be flat and square to start with, but if they're not nicely lined up you'll have a hell of a time sanding it flat once it's dry. We use one of these OMAS Glue Joint Cutter Head d=30 D=125 Z=2 V= B=60 at Scott+Sargeant Woodworking Machinery / UK in the spindle moulder as is has the double effect of keeping the boards aligned over the full length as well as increasing surface area for the glue, but a biscuit joiner would be your tool of choice. If you get that bit right, a simple electric belt sander (and practise) is all that's needed to get it cleaned up, ready for the random orbit sander. That's how we used to sand all our table tops until we bought a 1350mm wide belt sander (30hp on the first head and 20hp on the second head), now we can do in 30 mins what would have taken the better part of a day and everything is dead flat.

To prevent warping, quarter sawn is best, but most timbers aren't readily available quarter sawn. When using crown cut, alternate the direction of the rings from one board to the next when you look at the ends.

Dunno about 3' jointers, but I have seen one at 2' wide. I've also seen a 4' wide thicknesser for sale but I wouldn't want to be paying the power bill

Hi

You can certainly get a really fine smooth surface with a cabinet scraper, but you cannot get a flat surface unless it was flat before you started scraping.

In my view, with a long hand plane (jointer, #7 or 8) and winding sticks and a fairly high level of persistence and skill you can get a very flat table surface. But, you must plane away ALL wood above the bottom of the deepest depression otherwise it cannot possibly be flat. It is hard work.

Alternatively, you need large machinery as found in a professional joinery shop - thickness sander or large table CNC router. Have you considered subcontracting to a local joinery?


Fair Winds

Graeme

Originally Posted by M.E.Terr

How do you make a solid wooden table top really flat, and so that it will stay that way?

Any tips gratefully received thanks.

Hi METERR
It seems that the first part of your question has been answered in the above posts .... as to how to keep it flat ... here are some tips.

1) as said above when doing the glue ups alternate the cups ans crowns. Often this will mean cutting the pith section out (if it is present) and just using meatier part. I tend to use 100mm wide planks at most .. narrower planks have less movement if you cant get quarter sawn stock.

When doing the glue up dont try to do the full width in one go ... do it in smaller sections as you will find that easier to align, and keep aligned during clamping.

You can also use compression joints (do a Youtube search for details) and these compress the ends and keep the moisture out.

Make sure that uou paint, dress or oild both the top and underneath with the same product ... sealed wood is less likely to cup.

I use breadboard ends with drawn dowels for affixing the breadboard. Deep mortices are needed for that process. I glue the breadboard only on the mortice section (about 75mm and spanning two planks).

The table top should be attached with holddowns and not screwed. I like to elongate the holdown screw holes.

Here some tables with breadboard ends that I made last year. The first one is made from recycled woods (oregon and cyprus .. and old deck substructure) and used as a potting table. The other two are Tas Oak.


IMG_2409.jpgIMG_2629.jpgIMG_2597.jpg

Originally Posted by Tahlee

Make sure that uou paint, dress or oild both the top and underneath with the same product ... sealed wood is less likely to cup.

Excellent point.

ALWAYS do the same thing to both sides, doesn't have to be finished to the same level but use the same product.

Many thanks, Elanjacobs, especially as insights into professional practices tend to be pretty hard to come by. No, I won't be buying a 30hp sander or a 4' thicknesser but, when sweating with the amateur methods, it makes me feel better to know that the superb results visible on some modern furniture probably benefitted from a major advantage in the workshop.

I had a look at the glue joint cutter and can see its advantages, now that you've told me. I think there is probably a half-inch router bit would do the same job in a router table. I will investigate.
All the best, John

Originally Posted by elanjacobs

As a 'pro', I can say that the most crucial part is when you're joining the boards together. Obviously they need to be flat and square to start with, [and] to prevent warping, quarter sawn is best, but most timbers aren't readily available quarter sawn. When using crown cut, alternate the direction of the rings from one board to the next when you look at the ends.

this is the most critical step

Originally Posted by M.E.Terr

Thanks Luke. I'm referring to tables I made in the past, up to about 3'6" x 5'. The tops did not come out as flat as, say, a piece of MDF. Problems I've had with hand planes arose in getting an even thickness, and around hard knots and burrs. Sharpness, I know, is essential, and a good set. Sometimes though, a straightedge shows a small depression in the surface that would involve planing all of the rest of the surface around it down to that minimum thickness. Daunting!

hi John

a further consideration is how "flat" is "flat enough" for a table. Obviously a table top can't be so uneven that glasses and such are tilted, but most, if not all, hand crafted tops will have some small depressions which are evident under a straight edge. However, f the depression is shallow and over a largish area and blended into the est of the top it won't be noticeable.

Originally Posted by ian

hi John

a further consideration is how "flat" is "flat enough" for a table. Obviously a table top can't be so uneven that glasses and such are tilted, but most, if not all, hand crafted tops will have some small depressions which are evident under a straight edge. However, f the depression is shallow and over a largish area and blended into the est of the top it won't be noticeable.

Good Morning John

As usual, Ian is absolutely right. In fact, if the surface is too uniform people will think it was machine made.....

The one exception is if the table is very highly polished. Then undulations can give you weird effects in the reflections.

My stuff never takes that high a polish so it is not an issue, for me.



Fair Winds

Graeme

Originally Posted by GraemeCook

As usual, Ian is absolutely right.

Hi Graeme I'm not sure about that, but thanks for the compliment

When I was making my first table I got lucky and received some advice from an old cabinetmaker.

First the top was flattened (as well as I could as a complete novice) with a hand plane.

Then came the clever bit, from the cabinetmaker, who lent me a piece of heavy steel, about 300 mm long, 150 mm wide and 25 mm thick (see pic). It had a piece of rubber conveyor belt glued to the base of the steel plate, which had brackets welded to each end. A piece of 80 grit sanding belt was clamped over the conveyor rubber and a rope attached to each end bracket. Then my wife and I pulled the weighty "sander" back and forth across the table top until it was beautifully flat ... took about and hour. Then we switched to 120 grit to make the top a bit smoother. Finally, it got a light rub down with an orbital using 180 grit.

I finished the table with acid cure lacquer which was hand rubbed to get a mirror finish.

Sounds brilliant

Can't see the pics on my phone but your commentary does it for me

All I need is a wife who likes the workshop too

Regards

Rob