Ideas for flattening 12’ ash boards & wood movement

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Forum topic by Flitch123 posted 08-28-2018 02:10 AM 712 views 0 times favorited 9 replies Add to Favorites Watch
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1 post in 514 days

08-28-2018 02:10 AM

Topic tags/keywords: question tip trick jig ash milling joining

Hello Everyone.
I am in need of some advice on how to flatten 12’ Ash boards (12’ L x 10” W x 8/4). I am making these boards into floating shelves. I would like to have the final thickness around 5/4. I am also concerned about wood movement for floating shelves that long. Any advice on wood movement? In terms of flattening I have watched a lot of videos using sleds for planers and router sleds. Is a router sled the easier option? I don’t want to just throw them through the planer because it won’t flatten them. I would love any advice that anyone has to offer, thank you so much.

9 replies so far

View bc4393's profile


86 posts in 1749 days

#1 posted 08-28-2018 03:34 AM

I’m not real sure about movement with Ash but the first thing that comes to mind is to cut them to the length of the shelves and then and have someone joint them for you with the right equipment. A 20 dollar bill to a cabinet shop is worth my time to rig up a sled for the planer or a router jig. If you’re really paranoid, maybe even cut them to 5 inches wide too, machine and glue them back together with opposing ring patterns to prevent cupping after the fact if you still want them to be 10 inches deep.. I had some 6 foot walnut that was flat enough to get them nice by alternating side on the planer after running them over the joiner. Even then I cut it down anyway to make a tabletop. With your thickness I would think it should be fairly stable but to expect that from a 12 foot board might be a tall order. (Again I don’t know ash that well)

View Robert's profile


3602 posts in 2087 days

#2 posted 08-28-2018 02:34 PM

Movement is only in the width. You shouldn’t have an issue with a floating shelf assuming they are fastened to the wall using dowels.

If you have an 8” jointer, it can be done.

If not, I would go with the router sled.

Finding a cabinet shop with a wide jointer is certainly an option, but that’s not always viable. I’ve tried to get a couple local cabinet shops to run a top through the wide belt sander one wouldn’t even talk to me the other was going to charge way too much. IOW they didn’t want to mess with it.

All this being said, if the boards are reasonably straight, I would just plane them. They are shelves, after all ;-)

-- Everything is a prototype thats why its one of a kind!!

View WoodenDreams's profile


883 posts in 517 days

#3 posted 08-28-2018 03:12 PM

I just made two 5’L x 24”W x 1 3/4”thick Maple floating shelves 3 weeks ago for a home improvement contractor. The shelves weighed 35 lbs each when completed, with out the brackets. What I did to solve any future warpage issues, I took the 2” x 12” x 12’ cut them to 5’3” lengths, then ripped them to 4” wideths. run them thru the Planer, jointed, and glued them back together. I did drill and put 1/2” x 22” metals rods thru them, since the brckets only come out 6 inches. Your shelves if they’re only 10 inches wide you don’t need the extra length rods. If your using the same type of brackets I used, they have a load rating of 135#’. Don’t worry about any wood movement on wideth or length. If you want, put a recessed hole in the wood and use a screw to tighten against the tubes. When you put the hidden brackets on or in the wall, have a slight upward angle for future drooping over time.

View Aj2's profile


2650 posts in 2404 days

#4 posted 08-28-2018 03:31 PM

Seems odd to me when someone buys wood bigger then they can handle.
Or their machines can handle.

-- Aj

View Snipes's profile


444 posts in 2851 days

#5 posted 08-28-2018 07:00 PM

There 2” thick now but you want them 1 1/4”? why so thin. If there just cupped the planer will flatten em, or sled for planer is an option. As others said movement is not an issue in this application.

-- if it is to be it is up to me

View Kirk650's profile


679 posts in 1355 days

#6 posted 08-28-2018 11:38 PM

Rip them to what fits on your jointer and flatten them and plane them, leaving them a bit thick.Then glue them up with cauls to be sure they are flat. Then finish up in the planer. Of course you’ll need to start with more than 12 inches to wind up with 12 inches of width.

View Richard Lee's profile

Richard Lee

260 posts in 1382 days

#7 posted 08-29-2018 12:59 AM

Seems odd to me when someone buys wood bigger then they can handle.
Or their machines can handle.

- Aj2

Maybe he got them for free.
Maybe he got them cheap.

View Aj2's profile


2650 posts in 2404 days

#8 posted 08-29-2018 01:37 AM

Seems odd to me when someone buys wood bigger then they can handle.
Or their machines can handle.

- Aj2

Maybe he got them for free.
Maybe he got them cheap.

Ha good one Richard either way now it’s going to cost him to play. Still no free lunch.

-- Aj

View jmos's profile


917 posts in 2976 days

#9 posted 08-29-2018 11:22 AM

As an alternative to a cabinet shop, you may also want to check to see if there are any ‘maker co-op’ type places around you. The ones where you pay a membership fee and get to use their equipment. Many times they have some large equipment. You might be able to strike a deal with them to just process your boards, rather than joining.

-- John

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