Thread: Attaching solid panel backer in a sideboard, accomodating for wood movement

4mm seems very generous for an expansion gap; depending on species you may be able to get away with less.

My thoughts would be to cut a 1/8" side bead along all the edges to give a bit of decoration and to hide the expansion gap in a shadow line; and probably just use brads to attach it through the quirk of the bead. Attaching through the dividers could also be done with brads punched below the surface and hidden under a speck of Timbermate.

Cool idea. So you mean a profile something like this
54F8218F-EE9F-4955-B980-999DB872B2CC.jpeg

And just Brad mail into the groove.
The bead softens the gap, and if I get it even on all sides with spacers, it will look intentional, and shadow line hides everything. Genius.

brad nailing top and bottom no drama for movement?

That’s the one; although I have it in a vintage Mathieson moulding plane rather than a router bit

Skinny brads should flex a little with the timber movement; put several along the centreline as the main mounting method so the wood movement is then effectively spilt into two halves and you only need a couple more further up.

Lets say your original 4mm was an accurate estimate, your method of flushing at the top means that the wood will expand the full 4mm down to the bottom. By dropping the panel 2mm and attaching along the middle the panel still grows overall by 4mm but now it’s doing it 2mm up and 2mm down. If you put additional brads halfway up each section the max movement at each one will only be 1mm.

Very nice. Thanks Chief. That is how I’m gonna do it!
Got the panel sized (allowing for a more modest 3mm total expansion across the width.

so close to being complete now. I’ve been working on this piece for nearly 12 months. Excited to get it finished!

Please post some pics when you're done. I've been following this thread and I'd like to see the end result.

cheers

ajw.

You bet AJW!
And if it turns out as well as I think it will, I may well get my photographer buddy to do some studio shots for me.

By the way, the old Domino came in very handy for doing the joinery on the stand, and also great as a slot cutter for the screws to attach the stand to the cabinet. Great tool, very flexible. Thanks again for the sale!

Most of the time I’ve found dry wood in an open non heated non air conditioned workshop will shrink a touch after a while when its in a house . I have seen expansion as well though but a lot less than shrinkage .

Nailing a panel through the Quirk of a bead is most probably going to mean it will split there if it does shrink enough .

I thought a fair bit about this before I decided to reply so maybe you’ve already started down that road .

One thing I know about cabinets and their backs. It’s one of the very first things that has to be decided when you start to plan a build .

Any way . What I think would do in this situation if it will fit . Build a slotted frame in 19 mm thick timber that fits the rebate and is flush at the cabinet back . It could have three sections to it . As in to long horizontal rails . Two vertices ends and two vertical dividers . If the cabinet is in three sections ? I can’t see it atm . And your hardwood back becomes a panel that fits the slotted frame . One long one or three shorter if the frame is in three sections . The frame could be glued in or just nailed . Still with a bead to the edge if you like . You then have a panel that is fitted as a panel should be so it can move .
Done this way it may mean you have to house the two vertical cabinet dividers into that back frame as well to get it all level with the rebate depth .

Rob

You mean something like this?

Slotted Frame.JPG

Almost like that . The top and bottom rail end in that image would have a rebate to match the opposite rebate of the cabinet . The panel would be thinner . One third of the rail thickness roughly . That matches the tenon size in the frame if done correctly and the easy way . 6.35 mm tenon and slot and a panel that is beveled around the edge to match the 6.35mm slot . 1/4 inch . So the the panel could be 8 or 9mm thick before it tapers down .
It’s the normal quality back building in way from 1830 to 1880 roughly . The frame would normally sit in a full rebate and not have to be a two sided rebate though . But if it had that the two Center cabinet dividers would have to be set back to suit . The beveled side can go on the inside or the outside . What ever you like the look of .

Rob.

Originally Posted by auscab

Most of the time I’ve found dry wood in an open non heated non air conditioned workshop will shrink a touch after a while when its in a house . I have seen expansion as well though but a lot less than shrinkage .

Nailing a panel through the Quirk of a bead is most probably going to mean it will split there if it does shrink enough .

I thought a fair bit about this before I decided to reply so maybe you’ve already started down that road .

One thing I know about cabinets and their backs. It’s one of the very first things that has to be decided when you start to plan a build .

Any way . What I think would do in this situation if it will fit . Build a slotted frame in 19 mm thick timber that fits the rebate and is flush at the cabinet back . It could have three sections to it . As in to long horizontal rails . Two vertices ends and two vertical dividers . If the cabinet is in three sections ? I can’t see it atm . And your hardwood back becomes a panel that fits the slotted frame . One long one or three shorter if the frame is in three sections . The frame could be glued in or just nailed . Still with a bead to the edge if you like . You then have a panel that is fitted as a panel should be so it can move .
Done this way it may mean you have to house the two vertical cabinet dividers into that back frame as well to get it all level with the rebate depth .

Rob

Thanks Rob. I appreciate your considered reply.
Agree. I shoulda considered this properly earlier, but this detail did slip through.

Unfortunately, the rebate is only 11mm in depth. A little bit small for frame and panel construction I think. I did consider F&P as an option earlier on, but there's been a big priority on the removal of detail as a general design approach, and I felt that frame and panel was be more of a maximalist approach. Same reason why I steered away from shiplap. So, I'd thought I would use a ply panel. Then I realised that if I wanted to buy a manufactured panel, I can't cover the span in 1 piece (1200 x 600 panels in blackwood veneer on birch). So I'd either have to have a custom panel made ($$$, and don't want to wait), or shop saw my own veneers and press onto a substrate of my choice. While that's a nice idea, and something I do want to learn, I don't have the equipment or time to go that option. That's how I came to the current solution of a solid panel using the same timber as the case.

I'm not super experienced, but my feeling is that 440 total width, the wood movement is probably going be alright.
I figure that I'll roll with the current plan (brad nails in strategic places), and if I strike a problem later, I can either repair it, or replace it with a different solution.
Either way, it should prove to be a good learning experience!

Originally Posted by auscab

Almost like that . The top and bottom rail end in that image would have a rebate to match the opposite rebate of the cabinet . The panel would be thinner . One third of the rail thickness roughly . That matches the tenon size in the frame if done correctly and the easy way . 6.35 mm tenon and slot and a panel that is beveled around the edge to match the 6.35mm slot . 1/4 inch . So the the panel could be 8 or 9mm thick before it tapers down .
It’s the normal quality back building in way from 1830 to 1880 roughly . The frame would normally sit in a full rebate and not have to be a two sided rebate though . But if it had that the two Center cabinet dividers would have to be set back to suit . The beveled side can go on the inside or the outside . What ever you like the look of .

Rob.

I was trying to understand what you meant by slotted, hence the drawing of a slotted frame, but your description now changes what I was thinking.

Regardless of the application (e.g drawer bottom/back panel) the panel should always by left floating/loose, traditionally glue blocks are used (say 75mm long and spaced at say 250/450mm centres depending on the size of panel to be held in place) and glued/pinned only to the carcase.

Attached plan (not to any sort of scale) shows a Plan View of what I was taught to be a traditional detail for fixing a loose panel to allow it to move.

Plan View.JPG

You have a rebate on 4 sides of the back . The top one is 6.35 high x 11mm . Same all around ?
Thats fine to take a frame .
The edge of the frame matches it in the opposite way . So it fits in flush .

Originally Posted by Camelot

I was trying to understand what you meant by slotted, hence the drawing of a slotted frame, but your description now changes what I was thinking.

Regardless of the application (e.g drawer bottom/back panel) the panel should always by left floating/loose, traditionally glue blocks are used (say 75mm long and spaced at say 250/450mm centres depending on the size of panel to be held in place) and glued/pinned only to the carcase.

Attached plan (not to any sort of scale) shows a Plan View of what I was taught to be a traditional detail for fixing a loose panel to allow it to move.

Yes I’m talking about standard panel and frame construction with a floating panel or three .
Not what’s in your last drawing though .

Like this .
The 6.35 looks thin but if the frame is glued in place It’l be stronger . Never to come out though .


EF3D5926-D85A-47C5-816C-95F5F795BFEC.jpeg

66F573C5-A9BB-45B4-B5F9-2D6EB60442D9.jpg