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Cross Grain Planing - Very Thin Piece?

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Forum topic by DerekJ posted 08-19-2016 09:06 PM 535 views 0 times favorited 22 replies Add to Favorites Watch
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DerekJ

80 posts in 347 days


08-19-2016 09:06 PM

Topic tags/keywords: cross grain plane planing cross grain tear out sos

I am making a walnut table top with sycamore accent pieces around the edge. Being the inexperienced (or just dumb) woodworker I am, I glued up the accent pieces along the end grain of the table top. I then planned to run the piece through my planer to get even thickness. The accent piece is 3/8” thick and I’m wondering if planing this cross-grain will just destroy it?

I can always cross-cut the accent piece off, plane the whole top and then attach new trim pieces to the end, but I’m concerned about being able to get a perfect thickness, since it will be a tabletop.

I don’t have hand planes, and have no experience using them so that’s not an option for this particular project. Any tips would be provided, and pictures are included below. (note that there is a scrap piece used for clamping as well – that will not be included)

-- Derek ~ Omaha, NE


22 replies so far

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JayT

4772 posts in 1670 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.

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

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DerekJ

80 posts in 347 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

4772 posts in 1670 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.

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

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gargey

457 posts in 235 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

457 posts in 235 days


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

Wood is a complete dickhead sometimes.

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DerekJ

80 posts in 347 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

4772 posts in 1670 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.

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

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DerekJ

80 posts in 347 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

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JayT

4772 posts in 1670 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.

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

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LiveEdge

486 posts in 1080 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.

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DerekJ

80 posts in 347 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

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gargey

457 posts in 235 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.

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DerekJ

80 posts in 347 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

80 posts in 347 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

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JayT

4772 posts in 1670 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.

-- "Good judgement is the result of experience. A lot of experience is the result of poor judgement."

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