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Cross Grain Planing - Very Thin Piece?

by DerekJ
posted 08-19-2016 09:06 PM


22 replies so far

View JayT's profile

JayT

6311 posts in 2751 days


#1 posted 08-19-2016 09:18 PM

How wide is your table top? If it’s very wide at all, you are going to have issues with seasonal movement on a cross grain glue up like that. The walnut is going to expand and contract with changes in temperature and humidity, while the sycamore will not. At the least, the glue joint will fail. At worst, the walnut will split because of being bound. Better solution is something like a breadboard end with the middle glued and the outer parts not to allow for the movement.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

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DerekJ

120 posts in 1427 days


#2 posted 08-19-2016 09:27 PM



How wide is your table top? If it s very wide at all, you are going to have issues with seasonal movement on a cross grain glue up like that. The walnut is going to expand and contract with changes in temperature and humidity, while the sycamore will not. At the least, the glue joint will fail. At worst, the walnut will split because of being bound. Better solution is something like a breadboard end with the middle glued and the outer parts not to allow for the movement.

- JayT

Thanks – I really know very little about proper technique on this stuff. The walnut is 8” wide x 49” long. On the outside of the sycamore pieces I planed to glue up another ~4” walnut with 45 degree mitered corners as a border.

I did just realize that I didn’t cut the panel to the correct length to allow for the walnut border so I will be cutting the ends off anyway. Any guides or how-to on the proper technique for the end pieces?

-- Derek ~ Omaha, NE

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JayT

6311 posts in 2751 days


#3 posted 08-19-2016 09:38 PM

So, if I am understanding correctly, your plan was to build something like this for the top?

If so, I think you are going to have all kinds of issues with wood movement. If you are wanting that grain design, veneer over a plywood substrate would probably be best. I don’t have any idea how you could accomplish that exact look with solid wood and not have issues.

If it was me, I’d probably do a walnut top with breadboard ends and then do the accent as an inlay.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

View gargey's profile

gargey

1013 posts in 1315 days


#4 posted 08-19-2016 09:41 PM

Its a huge pain in the ass. Google “breadboard” or search it on this site.

8” is borderline… If you project is built somewhere with low humidity and lives somewhere with low humidity it will probably be fine (despite the doom-sayers), but if it is exposed to real swings in humidity you might want to up the insurance on your house because every inch of cross-grain glued to long grain is equal to 745 lbs of TNT if it fails.

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gargey

1013 posts in 1315 days


#5 posted 08-19-2016 09:42 PM

Wood is a complete dickhead sometimes.

View DerekJ's profile

DerekJ

120 posts in 1427 days


#6 posted 08-19-2016 09:45 PM

JayT, you beat me to it… Yes, I want to do exactly that. Let me ask this, then. If I would do it all out of walnut and still have the mitered boarder, would I still have issues with movement? I really don’t understand what causes issues and what doesn’t.

If that would work, I could route in the accent piece and be okay with it.

Alternatively, if that mitered frame is going to cause issues no matter what, I can just edge glue four walnut boards together and then route into that, but that would be least desirable.

For the record, my crude drawing is nowhere near as nice as your sketch:

-- Derek ~ Omaha, NE

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JayT

6311 posts in 2751 days


#7 posted 08-19-2016 09:45 PM


8” is borderline… If you project is built somewhere with low humidity and lives somewhere with low humidity it will probably be fine (despite the doom-sayers)

- gargey

I agree on the borderline for an 8in top, that’s why I asked size. With wanting to add another 4in all around of mitered. I feel that pushes beyond the border. Since the OP’s signature line says Omaha, I think we can safely assume there will be some drastic swings in humidity.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

View DerekJ's profile

DerekJ

120 posts in 1427 days


#8 posted 08-19-2016 09:46 PM



Its a huge pain in the ass. Google “breadboard” or search it on this site.

8” is borderline… If you project is built somewhere with low humidity and lives somewhere with low humidity it will probably be fine (despite the doom-sayers), but if it is exposed to real swings in humidity you might want to up the insurance on your house because every inch of cross-grain glued to long grain is equal to 745 lbs of TNT if it fails.

- gargey

It’s being built in relatively high humidity Omaha, Nebraska – but is going to live at 8400 feet in my dad’s Colorado home with relatively no humidity… Thoughts?

-- Derek ~ Omaha, NE

View JayT's profile

JayT

6311 posts in 2751 days


#9 posted 08-19-2016 09:50 PM


Let me ask this, then. If I would do it all out of walnut and still have the mitered boarder, would I still have issues with movement? I really don t understand what causes issues and what doesn t.

- DerekJ

The mitered border is going to cause issues no matter what if the center is solid wood. Wood will expand and contract most across the grain, not very much in the direction of the grain. You might be able to get away with doing the center in walnut plywood with a mitered border. The plywood would be much more stable and at only 4in wide, you would probably be OK with the border.

For a similar look in solid wood, I’d do the top like this

Breadboard ends on the walnut and then inlay thin strips of sycamore for the accent. There would be ways to do the sycamore as full depth glueups, but the inlay would be easier in my mind.

It s being built in relatively high humidity Omaha, Nebraska – but is going to live at 8400 feet in my dad s Colorado home with relatively no humidity… Thoughts?

- DerekJ

It’s going to move quite a bit as it adjusts to the much lower humidity at elevation in Colorado. Better to plan for it now instead of putting a lot of time and effort into a nice project and end up having a bunch of gappy joints when the wood shrinks some more.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

View LiveEdge's profile

LiveEdge

600 posts in 2160 days


#10 posted 08-19-2016 09:52 PM

To answer your original question that nobody is answering, you could probably plane the piece if you took small bites with the planer rather than trying to do it faster. If you are new to woodworking, then go for it. This is your first piece and isn’t going to wind up in the Guggenheim. If it fails because of wood movement, then so be it and you learned something.

View DerekJ's profile

DerekJ

120 posts in 1427 days


#11 posted 08-19-2016 10:00 PM



To answer your original question that nobody is answering, you could probably plane the piece if you took small bites with the planer rather than trying to do it faster. If you are new to woodworking, then go for it. This is your first piece and isn t going to wind up in the Guggenheim. If it fails because of wood movement, then so be it and you learned something.

- LiveEdge

Thanks!

Breadboard ends on the walnut and then inlay thin strips of sycamore for the accent.
...
It s going to move quite a bit as it adjusts to the much lower humidity at elevation in Colorado. Better to plan for it now instead of putting a lot of time and effort into a nice project and end up having a bunch of gappy joints when the wood shrinks some more.

- JayT

I guess I must not fully understand the breadboard end concept. Do the breadboard ends allow for the panel to move, or for the ends to move?

-- Derek ~ Omaha, NE

View gargey's profile

gargey

1013 posts in 1315 days


#12 posted 08-19-2016 10:00 PM

Just to make sure you understand:

Wood expands and contracts perpendicular to the grain. Up to 1/8 inch per foot, as a wild generalization.

Along the grain, it doesnt expand or contract at all.

That is why you must avoid gluing mismatches. Explosions.

View DerekJ's profile

DerekJ

120 posts in 1427 days


#13 posted 08-19-2016 10:03 PM



Just to make sure you understand:

Wood expands and contracts perpendicular to the grain. Up to 1/8 inch per foot, as a wild generalization.

Along the grain, it doesnt expand or contract at all.

That is why you must avoid gluing mismatches. Explosions.

- gargey

This explains why the “farmhouse style” table I bit with 2×8’s and glued edge to edge, but also screwed down to the frame – exploded while eating!

-- Derek ~ Omaha, NE

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DerekJ

120 posts in 1427 days


#14 posted 08-19-2016 10:11 PM

Thanks everyone for your comments on this stuff – I like being able to learn without making mistakes.

I think the solution I’m going to go with is just edge-glue a 48×16” panel and sand the heck out of the end grain. I did this with a TV stand in my basement and am happy with the look. This will save me a lot of frustration trying to learn a new technique on a piece being built for my dad. This way I can just rip off the sycamore and start fresh with the 8” walnut panel I already have glued up.

-- Derek ~ Omaha, NE

View JayT's profile

JayT

6311 posts in 2751 days


#15 posted 08-20-2016 12:26 AM


I guess I must not fully understand the breadboard end concept. Do the breadboard ends allow for the panel to move, or for the ends to move?

- DerekJ

Breadboard ends allow the panel to move, while the breadboard provides support to help keep the panel from cupping and covers up most of the end grain. Here’s a good article from Wood Magazine on building one.

http://www.woodmagazine.com/woodworking-tips/techniques/joinery/breadboard

There are other ways, too, just Google up “breadboard end construction” to find them. What they all have in common is that the center of the panel is glued to the breadboard and no glue is applied further out so as to not restrict the movement. In the article linked above the mortise in the breadboard is wider than the tenon on the top. That allows the tenon to expand and contract freely, while still keeping a finished look that isn’t affected by the movement.

Didn’t mean to avoid the original topic, but one of the most common mistakes beginning woodworkers make is not allowing for wood movement on panels and having to redo a project they put hours and hours into. I just wanted to try and help you avoid that mistake before putting in the time and effort. On the original topic, running a board cross grain through a planer will most likely result in some blowout on the trailing edge, even with really light cuts. You can allow for it by either using a sacrificial backer board or by making that piece a bit over wide and cutting of where it blows out.

-- https://www.jtplaneworks.com - In theory, there is no difference between theory and practice. In practice, there is.

View clin's profile

clin

1070 posts in 1536 days


#16 posted 08-20-2016 01:17 AM

I like the look of the original design, but I too can’t see how to make it work without using plywood in the middle section. I also agree that the miter corners can be an issue as the get wider.
An option for solid wood int he middle, as planed, it I suppose you could create a floating panel, just like a cabinet door. In this case you’d have a groove around the accent piece that was actual the gap that allows the center section to expand as needed. I think I’ve seen table like this. Might be the very reason they do it that way.

As I understand it, the problem with the miters is that the wood actually won’t maintain the 45 deg angle as it expands and contracts. You can add splines or dowels or similar joinery method on the miters to help hold them together.

As to the original question, I would have planed the board to final thickness before adding the accent and then used a router to trim the accent. Or after adding the mitered boarder, just sanded the accent down.

One last point when it comes to things like the original question. Sometimes the easiest thing to do is just build a test piece and see what happens. You might confirm that yep, it tore the heck out of that accent piece. Or gee that work okay after all.

You don’t necessarily want to avoid doing something just because some guys on a woodworking forum think it won’t work right. Unless the advise comes from someone who has actually done what you are doing, it’s just an informed opinion at best. Though if you must do it on the actual work piece, then best to be conservative. I’m talking about the planing, not the wood movement. That’s a well documented issue.

-- Clin

View bondogaposis's profile

bondogaposis

5556 posts in 2891 days


#17 posted 08-20-2016 01:54 AM


JayT, you beat me to it… Yes, I want to do exactly that. Let me ask this, then. If I would do it all out of walnut and still have the mitered boarder, would I still have issues with movement? I really don t understand what causes issues and what doesn t.

If that would work, I could route in the accent piece and be okay with it.

Alternatively, if that mitered frame is going to cause issues no matter what, I can just edge glue four walnut boards together and then route into that, but that would be least desirable.

For the record, my crude drawing is nowhere near as nice as your sketch:

- DerekJ

Yep, that is the panel of doom. A rite of passage for nearly every new wood worker. Read about it here.

To answer your original question, it would be best to chamfer the outside edge of that sycamore strip otherwise it could spelch. I think it would be ok if you take really small bites and chamfer the end strip.

-- Bondo Gaposis

View JBrow's profile

JBrow

1368 posts in 1460 days


#18 posted 08-20-2016 04:35 AM

DerekJ,

I really doubt you are dumb. I took a look at your gallery and your projects suggest otherwise. And seeking advice of others, evaluating those comments, and then proceeding with your project strikes me as a pretty smart thing to do!

While I agree with all that has been said, I thought I would embellish what others have said and add some of additional thoughts of my own that I hope may be helpful.

Mitred Border.

Were it me, I would forsake the mitred border, although substituting plywood for the solid wood top would allow the solid mitred border to remain (if it can be flushed up to the plywood). I personally like the look of exposed end grain. When the end grain is sanded to 220 grit, and enough finish is applied to the end grain so that the finish no longer soaks into the wood, it yields good looking results, at least to my eye.

If you want to stick with your original plan of a solid wood table top set in a mitred border frame, frame and panel construction comes to mind. The frame of walnut could be mitred, best reinforced with splines, biscuits, or dowel or half lapped. A groove cut into the inside edges of the mitred frame would accept the tongue milled into the solid wood panel. Some room would have to be left so that the unglued free floating solid panel could expand and contract. The biggest problem with this method is that a crack exists around the perimeter of the solid panel, which will get larger or smaller with changes in humidity. The crack also invites dirt and grim over time.

I personally dislike bread board ends and do not use them (although a project may come up where I would). The main reason I dislike the bread board end is that, with allowance for seasonal movement, the top will expand and contract along it width while the bread board remains pretty close to its original length. As a result, there are times when the edges of the table do not align with the bread board ends; sometimes the edges of the top are set back a bit while at other times the table edges may extend past the ends of the bread board. This affect makes mitreing the perimeter of a solid wood panel difficult and, even if the ends of the top allow for wood movement, the top could crack and/or the mitred joints open up. As already said, plywood behaves much better when a perimeter of solid wood is desired.

Sycamore Inlay.

I think the sycamore accent strip could be incorporated into the solid walnut top with some difficult and careful glue-ups. The only question is whether the expansion and contraction of sycamore differs too much from that of walnut. While imperfect, comparing Volumetric Shrinkage (VS) and the ratio of Tangential to Radial Shrinkage (T/R) of walnut compared to American sycamore can help. I looked at The Wood Database, a handy resource, add found that for Walnut VS = 12.8%, T/R = 1.4 compared to American sycamore VS = 14.1, T/R 1.7. I really cannot say it is close enough to avoid problems, but these values seem close enough to me – but this is only a guess.

http://www.wood-database.com/

At any rate, a doable but complex and difficult multi-step of glue-up can probably achieve the inlay look you are after while minimizing worries about failure due to wood movement. To incorporate the sycamore into the field of the walnut, a sycamore panel can be glued up, long enough so that the sycamore panel will yield two end strips. The sycamore end strips are glued to the ends of the walnut. End pieces cross cut from an oversized walnut center section panel can then be glued to the sycamore ends. With the ends glued up, the additional walnut can be glued on to achieve the table top’s final width. In this configuration, the grain in the sycamore and walnut are all parallel.

End grain glue-up is an inherently weak joint. Therefore reinforcing the end grain joints with biscuits, dowels, splines, or maybe using a half-lap joint would be required. Ensuring the sycamore inlay corner joints are tight and the width of the top perfect after gluing the sycamore edges and sycamore and walnut ends requires careful planning and accurate cuts.

Flushing Up.

Whenever confronted with flushing up an edge of a board with the surface of a large panel, such as when edge banding is glued to plywood to hide the plywood ends, I like to glue the solid wood edge banding a little proud of the surface of the panel. This leaves a slight lip on the solid wood strip that then requires trimming. My first thought is to use a flush trim bit in the router. The router base rides on the wooden strip that must be trimmed flush and bearing rides on the panel. If the router base is a little tippy, then some creative set up to afford good support for the router base can make this method work.

A router alternative to the flush trim bit is a straight bit with riser strip on which the router base rides. The riser strip is attached with clamps or double-sided tape to the surface of the panel and against the lip of the wooden strip that is to be made flush with the panel. A piece of ¼”thick hard board can work as the riser strip so long as the riser strip keeps the router base above the lip of wood strip to be trimmed flush. With the router setting on the riser strip, the depth of cut is set by lowering the straight router bit until it just contacts the surface of the panel. However, my preference is to lay a piece of computer printer paper on the panel and lower the straight to just contact the paper. The router base then rides on the riser strip and the straight bit removes material on the wooden strip to be trimmed. The last step is to dress the wooden strip with sand paper to make it absolutely flush to the panel.

If the router/flush trim bit method is not practical, such as when an obstruction precludes using the router, I rely on the combination of the hand plane and/or chisel, cabinet scrapers, and sand paper. The hand plane gets me close to flush. The chisel works best in corners. The cabinet scrapers get me a little closer to flush. Sand paper plus patience takes the surfaces to flush. The hand plane and cabinet scraper make the process go a little faster. The entire process could be done with a lot of patience and perseverance with just sand paper.

View nightguy's profile

nightguy

213 posts in 1202 days


#19 posted 08-20-2016 05:29 AM

If you want to stay with your original design, find a shop with a drum sander to smooth it out, no tear out!!

View DerekJ's profile

DerekJ

120 posts in 1427 days


#20 posted 08-21-2016 03:42 AM

All,

I posted a pretty “simple” question and expected a few yes or no answers; you’ve all proven why this forum is so highly rated and why woodworking is such an appealing hobby! There’s no end to the learning and no shortage of experienced craftsman willing to help!

I don’t know why I didn’t think to oversize the trim pieces and use a flush bit in my router – just haven’t fully mastered the capabilities of my router!

I fully appreciate the warnings about my panel-of-doom construction. Today I ripped all the sycamore pieces off and glued up an edge-to-edge panel measuring 16×49 – I’ll sand and finish the end and then practice inlaying the sycamore for the accents.

I appreciate ALL your help and will absolutely be posting again when it comes to the best way to attach an apron to the table legs :)

-- Derek ~ Omaha, NE

View TheFridge's profile

TheFridge

10859 posts in 2026 days


#21 posted 08-21-2016 03:50 AM

It may tear out and it may not. I’ve never had good luck unless my planer knives were brand new but it was still luck.

I’d use a scraper to get the banding flush to its surroundings if you ever did something like that. My personal go to would be a block plane.

The only way your original thought would remotely work without ply is a floating panel and you wouldn’t want to do that on a table.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View DerekJ's profile

DerekJ

120 posts in 1427 days


#22 posted 09-17-2016 05:44 PM

Thank you all so much for your feedback! I asked a simple question and it completely changed the course of my project! I’m finished and couldn’t be happier with the results. I’d love for you to take a look and welcome all feedback to grow my skills:

http://lumberjocks.com/projects/267970

-- Derek ~ Omaha, NE

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