LumberJocks

Cross Grain Joint

  • Advertise with us

« back to Joinery forum

Forum topic by jcwalleye posted 11-30-2017 01:47 AM 408 views 0 times favorited 14 replies Add to Favorites Watch
View jcwalleye's profile

jcwalleye

306 posts in 2913 days


11-30-2017 01:47 AM

Topic tags/keywords: cross grain

It’s been a while since I lasted posted on Lumberjacks and hope you’re willing to offer some opinions.

I’m building a simple riser made of 9/16” red oak. The base and top of the riser will be a glued up panel 18” deep. I’d like to attach the sides, and a center divider to the top and bottom with a dado or rabbit, glue, and brads. It’s a classic cross grain dilemma. My question is ‘how much expansion should I expect, considering that the oak is all quarter sawn? Is it likely to blow apart with seasonal movements? I live in a very arid climate.

Here is a picture of the materials I plan to use and showing the cross grain.

Can you suggest another joint that is simple yet somewhat durable? Worst case scenario is that I’ll glue up another panel and cut that across the grain, effectively matching the sides to the base and top.

Thanks much. Joe.

-- Trees, a wonderful gift --Joe--


14 replies so far

View bondogaposis's profile

bondogaposis

4483 posts in 2191 days


#1 posted 11-30-2017 02:03 AM

What’s a “riser”?

-- Bondo Gaposis

View jcwalleye's profile

jcwalleye

306 posts in 2913 days


#2 posted 11-30-2017 02:05 AM

Just a small shelf to set a flat screen TV on. Raise it 6” or so. It’ll have a top, bottom, 2 sides, center divider, maybe a back to prevent racking

-- Trees, a wonderful gift --Joe--

View bondogaposis's profile

bondogaposis

4483 posts in 2191 days


#3 posted 11-30-2017 02:25 AM

Oh, I thought you were building stairs, and the picture made no sense for that. Being 18” deep you are going to get some wood movement even with 1/4 sawn. If you glue the top down it might split but will still work as a shelf. If you skip the glue, the brads will flex and allow movement with out stressing the top. You could glue the front edge and let the movement go to the back.

-- Bondo Gaposis

View jcwalleye's profile

jcwalleye

306 posts in 2913 days


#4 posted 11-30-2017 02:35 AM

Good ideas. Glue and brads at the front, brads only at the back?

It’s for a friend and he’s not going to be fragile with it. He should be able to grab it anywhere and not worry about the unit’s strength.

Other thoughts, tongue and groove for the top and bottom (lot of work). Sliding dovetail (too complicated).

-- Trees, a wonderful gift --Joe--

View Loren's profile

Loren

9639 posts in 3488 days


#5 posted 11-30-2017 03:05 AM

I would make the sides and dividers with
the grain going the other way.

I expect the 18” top would move about 3/16”
in quartersawn oak. As I recall flatsawn
moves about 1/4” per 12” span and quartersawn
half that.

View jcwalleye's profile

jcwalleye

306 posts in 2913 days


#6 posted 11-30-2017 05:07 AM

Great info Loren. That’s probably the way to go. Thanx

-- Trees, a wonderful gift --Joe--

View Lazyman's profile

Lazyman

1509 posts in 1227 days


#7 posted 11-30-2017 05:22 AM

So you are basically making a narrow box with a divider that is laying on its side, right?

Loren, why wouldn’t you want the grain on the vertical pieces, ends and dividers to be the same as the horizontal? It seems like if they we all oriented the same way, they would be more likely to move together? Maybe I don’t understand what you mean.

Also, I would think you would want the glue in the middle instead of close to the front or back . Similar to how you attach breadboard table ends. That way you only get half the movement at the edges? Again, maybe I’m missing something?

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

View Loren's profile

Loren

9639 posts in 3488 days


#8 posted 11-30-2017 05:29 AM


Loren, why wouldn t you want the grain on the vertical pieces, ends and dividers to be the same as the horizontal? It seems like if they we all oriented the same way, they would be more likely to move together? Maybe I don t understand what you mean.

- Lazyman

I’m saying to do what you’re saying I think.

What the OP was wanting to do was the sort of
thing where you really have to use something
like sliding dovetails for it to work.

View Rick_M's profile

Rick_M

10645 posts in 2220 days


#9 posted 11-30-2017 05:59 AM

If the pieces are oriented correctly, there will be no cross grain joints.

-- http://thewoodknack.blogspot.com/

View jerryminer's profile

jerryminer

812 posts in 1281 days


#10 posted 11-30-2017 08:38 AM



If the pieces are oriented correctly, there will be no cross grain joints.

- Rick_M

Right. I agree. I think Loren and Lazyman are saying the same thing. Top and bottom grain running left-to right. Vertical pieces grain running top-to- bottom. (all parts are 18” glue-ups)

-- Jerry, making sawdust professionally since 1976

View HorizontalMike's profile

HorizontalMike

7665 posts in 2754 days


#11 posted 11-30-2017 12:47 PM



It s been a while since I lasted posted on Lumberjacks and hope you re willing to offer some opinions.

I m building a simple riser made of 9/16” red oak. The base and top of the riser will be a glued up panel 18” deep. I d like to attach the sides, and a center divider to the top and bottom with a dado or rabbit, glue, and brads. It s a classic cross grain dilemma. My question is how much expansion should I expect, considering that the oak is all quarter sawn? Is it likely to blow apart with seasonal movements? I live in a very arid climate.
...[snip]...
Can you suggest another joint that is simple yet somewhat durable? Worst case scenario is that I ll glue up another panel and cut that across the grain, effectively matching the sides to the base and top.
Thanks much. Joe.
- jcwalleye

IMO, SKIP the glue portion and let the divider slide(shrink/swell) in the dado. Attach the sides and divider with brads only, and not too many of them. You want to allow that movement within limits.

The only other option I see would be to use veneered plywood, because that would minimize/eliminate shrink/swell and any cross-grain issues.

-- HorizontalMike -- "Woodpeckers understand..."

View jerryminer's profile

jerryminer

812 posts in 1281 days


#12 posted 11-30-2017 05:19 PM

Brads only, without glue, would be a problem if this thing is handled roughly—like picking it up from the top only, with a heavy object or two sitting on the bottom. You’d be pulling the brads out as you lift.

But if it just sits still with weight on top, it’ll be fine. I would definitely put some kind of back in it.

-- Jerry, making sawdust professionally since 1976

View jcwalleye's profile

jcwalleye

306 posts in 2913 days


#13 posted 12-02-2017 01:23 AM

Thanks all. Loren was first to suggest what I actually ended up doing, reorienting the side’s grain to match the top and bottom. That the top could move up to 3/16” was compelling. And no joint, other than a sliding dovetail, could offer much strength and survive the cross grain expansion. I’d hoped there was a simple one, but couldn’t come up with it. Thanks again.

-- Trees, a wonderful gift --Joe--

View bbasiaga's profile

bbasiaga

1011 posts in 1835 days


#14 posted 12-02-2017 01:43 AM

In the TV stand in my projects list I just used a pin in the back, so the whole riser was mechanically free of the table top, but still held in place so it didn’t move when moving the TV. So far, so good.

Brian

-- Part of engineering is to know when to put your calculator down and pick up your tools.

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com