Flattening a table top.

[DamnYankee]

I've read posts about flattening a table or work bench top by using a router and a jig that would span the table. Seems like it would work fairly well but take a long time.

It got me thinking though about building a jig but setting it up to use a portable electric planer instead. Seems like 3 1/4 inch cut would make a quick job compared to even a large router bit.

What would be the downfalls?

Just being curious. I don't have a top to flatten at the momemt but I could see doing it sometime.

Bryan

[Mike in Mystic]

I haven't used a power planer before, but I think one of the virtues of the router method is that it is very easy to control the depth of cut and to make passes with small incremental changes in depth. How easy is it to control the depth of cut with a power planer? This might be one downside if it isn't precise or give you the ability to make very small adjustments.

[bf]

Here's the problem I see with using a portable planer to flatten a table top.

The portable planer can be adjusted to take at most around 1/4" off (I think it's less than that, but you'll see the point).

So the problem is, how do you make rails that thin that will support it (not bow) while spanning the length of a table. In other words, I can't see how you'd make the jig to do this.

With a router, you can get a long bit that will go down far enough so this isn't a problem.

[Morris Dovey]

It works as well as the jig is flat. Time depends on the size of the bit, the amount of overlap between cuts, and how fast you move the router. If you cut in a rectangular spiral, there won't be any waste motion with the router.

The planer only cuts in the foreward direction, so half of the time used will be wasted. This means that a router with a 2" bit will finish the job faster than a 3-1/2" planer.

The planer uses the existing surface as its reference. A router jig uses the rails the gantry rides on and the gantry rails as its reference. There are good and bad points with both approaches.

You're welcome to use the link below and click on "Miscellaneous" to see some photos of a heavy (1000+ pound) router setup. It flattens its own table to better than ±1/128". The photos might provide some ideas for how you might build a smaller and less expensive flattener...

[mac davis]

seems very possible... we once used a portable balt sander in a pinch... mounted it between two 4' sections of water pipe like a panel saw and kept making passes until the tables were flat..

mac

Please remove splinters before emailing

[TWS]

The problem I see is that direction that each tool cuts is different. The router will cut on the side of the bit so the forces are predominantly horizontal, along the same plane as the surface you are trying to flatten. This only requires a frame rigid enough to carry the weight of the router.

In the case of the electric planer, however, the planer digs down into the wood so the predominant force is vertical. A planer works because the face plate on the planer provides a surface to push back on the wood being pulled up by the blade. If you try to suspend the planer then your frame will need to provide this force and will need to be

*substantially* more rigid than with the router. Furthermore, the dynamic vibration caused by the alternating blades and the springiness of the frame will undoubted cause substantial tearout.

I think it is extremely unlikely to successfully create a usable fixture using an electric planer.

TWS

[Lew Hodgett]

RE: Subject

That's why they make drum sanders.

A little travel time, $20-$30 if you are not in a hurry, and the job is done by a commercial shop.

At least that's how I do it.

Lew

[Steve Johnson]

[DamnYankeeBastard]

You could. They're very aggressive though. The jig would keep if flat(ter).

Bryan

[Paul Kierstead]

They are not long enough; at least, I have never seen one long enough. It takes a fairly long sole to flatten a large area; jointer planes are on the order of 20"+ long. Now you can do fairly well with careful application and testing using a shorter plane, but it takes a while and very light passes, something 'lrectic planes are pretty bad at.

PK

[TWS]

You could. In fact there was an article in a recent FWW that described the technique on fairly large pieces. I could see using a power planer to take out sections where the twist or dimension was too thick by a quarter inch or more but 'I'm not sure whether I would ever use that technique to do the finishing flattening, but that's just me, YMMV.

In my post here, however, I was responding to OPs suggestion of using a frame to provide a flat reference for a power planer. The technique works for Routers but, as I described, wouldn't work for a power planer. TWS

[bridger]

you can. the cordless one leaves a better surface, but the 'lektric one is great for hogging off big 'ol hunks.