uneven boards.

[Andrew Barss]

: > You're gonna want to do something to that 4' piece of plywood to make : > sure it remains dead flat, otherwise it's going to follow whatever : > peaks and valleys the boards have. It'll make them smooth, but not : flat, : > unless you rigidify things.

: If you can get a piece of 1/2" (9 ply) or 5/8" (11) ply birch ply to : bend when being used as a 48" long, long board, you are a hell of a : lot better man than I am, which is entirely possible.

: You are also using it improperly.

I'm completely confused. You say that a 48 inch long, four inch wide piece of plywood is capable of staying flat enough to make another board flat to within a few thousandths of an inch. This implies that the piece of ply will not flex, beyond a couple thousandths, as you apply pressure to it using a couple of handles.

Steel would do that. Plywood would flex at least an order of magnitude, probably two, beyond that. That is, I would expect a four-foot long piece of half-inch ply to easily flex at least a tenth of an inch along its length as you apply differential pressure to it.

Do you really say what I think you do?

-- Andy Barss

[Andrew Barss]

: > You're gonna want to do something to that 4' piece of plywood to make : > sure it remains dead flat, otherwise it's going to follow whatever : > peaks and valleys the boards have. It'll make them smooth, but not : flat, : > unless you rigidify things.

: If you can get a piece of 1/2" (9 ply) or 5/8" (11) ply birch ply to : bend when being used as a 48" long, long board, you are a hell of a : lot better man than I am, which is entirely possible.

To clarify, are you talking about a piece of ply which is

5/8" in the dimension perpendicular to the surface being flattened? or is it rotated so there is 4" perpendicular, and a 5/8" surface with sandpaper on it?

I can imagine the latter being inflexible to the extent you describe it, but no the former.

-- Clarifyingly yours,

Andy Barss

[Lew Hodgett]

Perhaps this will help.

You use a long board in conjunction with a fairing batten.

Take a few strokes with the long board, then check your work with a fairing batten.

Using the back edge of a 3/4" x 3/4" x 1/16" x 96" aluminum angle as a batten, you litteraly look for daylight between the work surface and the angle.

A 1/32" gap looks bug enough to drive a truck thru .

Lew

[henry]

If this is a one time project I like the time saver anwser. If you are are interested in working wood which I assume you do than I would suggest to learn to fix your mistakes which as stated before proably were due to not face jointing.The anwsers above that I like is to either cut and re glue or buy a used # 6 or 7 plane, and make some winding sticks. I purchased one on e-bay, flattened it on glass and put a hock blade in it and use it often. Take some swipes on the back side to learn. The pencil mark idea is a good one as well. Remember what ever method you use will yeild a thickness which is less than you had planned and depends on how off you were. If you started over would you have use for the old top?

[Mekon]

Thanks all for your answers. I appreciate them all.

A couple of people have suggested that the cause of my problem is that I didn't face joint the boards. I did face joint them, the problem is not that there are gaps in the joint but that one board is higher on one side and obviously lower on the other.

I can't start over for a couple of reasons beyond that the original purchase almost required me to discuss the project with my bank manager. Resawing the boards apart would leave either the top too narrow or require another board.

I called around and my board is now 20mm wider than the 400 maximum possible on the few places that will sand this for me and anyway Dave (Teamcasa) struck a nerve when he suggested that if others do it I might not be able to say I built it myself. The 'router carrier' that he suggests sounds like the jig I made a while ago without knowing what I was making. Reinventing the wheel I suppose.

There are no Woodcraft stores in Brisbane Australia.

I googled for winding stick pictures but found nothing.

I'll post pics in alt.binaries.pictures.woodworking and on my site, so the curious can see what happend next!

Thanks again

Mekkon

[henry]

Winding sticks are easy to make and many past magazine issues have articles.

[Peter Huebner]

I thought that was one of the possibilities, having had similar problems with bisquit jointing when I started out with that technology.

The best remedy for that, in my opinion, is a very sharp finishing plane, at 45 degrees or even 90 degrees across the grain to get rid of the step (run plane towards the high step so's not to get tear-out), then a cabinet scraper or maybe a random orbital sander to clean up.

-Peter

[Stephen M]

Ah yes. Some swear by biscuit joiners, I swear at them. biscuits add little or no strength to a joined top. If your equipment/technique is good enough so that you can use biscuits to aid alignment, then go for it. Mine isn't.

I don't have any difficulty aligning glue-ups by hand. What I don't do is any more than 2 seams in a clamp-up, usually only one.

Next time, try aligning the boards manually. If the seams are well-jointed (that is, you do not have to ben the wood to close the joint), I find that I can glue the next seam in 15 or 20 minutes.

Cheers,

Steve