Face-jointing a big plank with a router bridge

[Jamie Buxton]

... why move the router from side to side instead of along the length of the planks?....

Either would do the job. However, with a nine-foot-long plank, there would be a lot of walking back and forth to do it your way.

[Chris Padilla]

I would have written my name in the plank and had fun with it but you guys just want to go in nice, even, BORING straight lines....

[Joe Petersen]

I've been milling my own lumber in slabs like this to try to build furniture in the same style (god willing). I see these are close to being quarter sawn and that helps, but will still have the tendency to cup.

How do you ensure no cupping on the boards? Is making sure they are completely dry enough?
Also, I cant tell how you joined the legs to the table. How was this done?

[Jamie Buxton]

I've been milling my own lumber in slabs like this to try to build furniture in the same style (god willing). I see these are close to being quarter sawn and that helps, but will still have the tendency to cup.

How do you ensure no cupping on the boards? Is making sure they are completely dry enough?
Also, I cant tell how you joined the legs to the table. How was this done?

The planks were not cupped very much at all from the drying process. They were 2 1/2" thick, which might have had something to do with it. They were air-dried for about six years, according to the miller I bought them from. My moisture meter says they're about 7% moisture content. That seems very dry to get from air-drying, but that's what it reads.

The base subassemblies are basically rectangles made with 2"x7" lumber. There's finger joints at the corner. There are through-holes bored through the top piece of 2x7. The holes are round near the middle of the table, but oval near the edges. 3/8" bolts go through the holes into holes tapped into the underside of the top planks. The tapped holes are about 1 1/2" deep, so there's lots of thread.

[Derek Stevens]

gorgeous wood. nicely done.

[Jon Banquer]

These rails are made from 2x4s fastened together in an L shape. The L’s flange provides a spot for the clamps without getting in the way of the bridge. I used green lumber for these rails. It is likely to move as it dries, so I made them in the morning and used them in the afternoon. I edge-jointed the top edge on my jointer. Its bed is 54” long, so outboard roller stands help manage the 10’-long rails. It is convenient that two rails are necessary, because I can test them against each other to confirm that they are jointed straight. I test the jointed edges face-to-face, and then side-by-side. If they match in both tests, they are straight.

What would others suggest as an alternative for making the rails out of?

Shims underneath the rails make the adjustment of the rails.

Could someone describe the process of how one would go about adding shims so that the strings just touch. How do you know where to add the shims?

Does the work also have to be shimmed?

Jon Banquer
San Diego, CA

[Norman Pyles]

Wow, that is way cool.

[Heather Thompson]

This is a great thread and beautiful work, but this a two year old thread so it may not come up on the radar of many.

Heather

[Jon Banquer]

This is a great thread and beautiful work, but this a two year old thread so it may not come up on the radar of many.

Heather

I thought it would be better to comment and ask questions on an existing topic before starting another thread on a topic that had already been discussed so I did a search first and found this thread.

If the response is poor to the questions I asked I'll start a new thread.

Thanks for pointing out that I might get a limited response because of the age of the thread. From what you wrote I take it there are some posters don't look at older threads.

[David Epperson]

I thought it would be better to comment and ask questions on an existing topic before starting another thread on a topic that had already been discussed so I did a search first and found this thread.

If the response is poor to the questions I asked I'll start a new thread.

Thanks for pointing out that I might get a limited response because of the age of the thread. From what you wrote I take it there are some posters don't look at older threads.

Well, I didn't see this thread before I started on my Bridge Router Planer/Jointer set up. I might have got a different route.
My problem was trying to flatten warped wood that would need to be cut too small for a planer. So I just clamp the pieces onto the work table with some sacrificial shims and bridge router them when needed along with the project piece. My bit is a little different though. I modified a slotting bit to take a flat head socket cap screw - so that it fits a little under flush - and mounted that on a mandrel. Got a 2" diameter "Planing Bit" for about $15 that way.

[Steve Jenkins]

I use a bridge and router to flatten big pieces also but a slightly different method. My work table is a 4x8 foot torsion box so is nice and flat. I lay the piece to be flattened on the table and shim it so it doesn't rock. My bridge consists of two pieces of aluminum angle long enough to span the work piece. They are fastened to two short pieces of 3/4 ply that I rip wide enough to give me the height I need for the thickness of the workpiece.
This gives me good support without having to make long rails and mess with getting them even.

[Dan Friedrichs]

Could someone describe the process of how one would go about adding shims so that the strings just touch. How do you know where to add the shims?

Does the work also have to be shimmed?

You only use 2 shims for the strings. One string gets run corner-to-corner without shims, and the other string goes corner-to-corner, but at each end, sits on top of a shim that is the thickness of the string. If the two boards being used as rails are perfectly coplanar, the strings would perfectly intersect each other. Since that can't happen, shimming one string lets it sit just barely on top of the other one.

If the lines just barely touch, then the rails are coplanar. That doesn't say anything about the relationship of the board to be surfaced to the plane formed by the rails, though. You should shim the work up so that it is a uniform distance from the strings (to minimize the amount of material you take off).

[Jon Banquer]

Dan,

Do I have this right?

If one string is sitting above the other string I would start by shimming the rails at the ends that the lower string is attached to till both crossing strings just touch?

If one string is riding on top of the other string I would start by shimming the rails at the ends that the upper string is attached to till both crossing strings just touch?

If I have this right would you recommend using wedge type shims to make it easier to get the strings to just touch where they cross?

[Jon Banquer]

I use a bridge and router to flatten big pieces also but a slightly different method. My work table is a 4x8 foot torsion box so is nice and flat. I lay the piece to be flattened on the table and shim it so it doesn't rock. My bridge consists of two pieces of aluminum angle long enough to span the work piece. They are fastened to two short pieces of 3/4 ply that I rip wide enough to give me the height I need for the thickness of the workpiece.
This gives me good support without having to make long rails and mess with getting them even.

Steve,

So you don't use rails at all and instead *slide* the two aluminum angles, that are attached to the two short 3/4 plywood pieces, which sit on your torsion box table top down the length of the piece you are flattening?

Each time you make a cut you slide the bridge down so you can take the next cut?

[Dan Friedrichs]

Dan,

Do I have this right?

If one string is sitting above the other string I would start by shimming the rails at the ends that the lower string is attached to till both crossing strings just touch?

If one string is riding on top of the other string I would start by shimming the rails at the ends that the upper string is attached to till both crossing strings just touch?

If I have this right would you recommend using wedge type shims to make it easier to get the strings to just touch where they cross?

Um, I guess I've never seen it done with shims UNDER the rails. Every time I've seen it done, one rail gets securely screwed to the side of the bench, and the other rail gets one screw in one end (holding it to the side of a bench), then clamped at the other end. You can carefully adjust (by pivoting on the single screw at the far end) until the strings touch, clamp it tight, then drive more screws to hold it.