Idea to deal with anticipated panel wood movement

[Jim Clendon]

Thoughts on the following?:
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I am working on a saw till cabinet to fit within my existing tool cabinet, which is why it looks as it does.

I am wondering what others think about gluing 4" of back panel to the carcus at the top and bottom and then screwing the balance of the back panel...

I just want the back panel well secured and want to try to prevent any splitting in the future of the back panel. If I glued and screwed the full perimeter, I know i will see intermediate cracking...

Thanks

Jim Clendon

[Kris Cook]

I am not quite understanding what you plan to do.

Is the back panel solid wood? Or sheet goods?

If those are fasteners showing around the perimeter, and the back is solid - you aren't allowing for wood movement that I can tell.

What are you fastening to? Solid wood or sheet something?

Do you have a picture of the existing cabinet that will be receiving this unit?

[Jim Clendon]

All solid wood
no sheet goods
anticipating shear lag to accommodate wood movement where screws are located
back panel is solid spruce
carcus material is white pine

[Carl Baker]

If you want to glue anything, I believe your approach of gluing the center of the panel is the right one. It's similar to breadboard edge construction; fix the center and let the outer edges "float."
I don't get a clear sense of scale here, but if you told me this thing is 24" wide, I would simply enlarge the screw holes on the back panel as you move toward the edges and get on with it...no worries. If this thing is 4' wide, I may change my answer slightly
Random comments (not critique) maybe just to spark an idea that makes you more comfortable:
Based on the drawing, the back panel appears to be as thick as the sides. You also indicate that you are dropping it into an existing cabinet, hence the shape. If the back is 3/4" material, maybe you eliminate the top piece all together. the back would be enough to support the other vertical dividers and eliminating the top takes away your biggest horizontal movement issue. if it's going into an existing cabinet, you probably don't need it for stability.
Another option is to keep the outer frame intact and approach the back the way they used to do old furniture before sheet goods... cut half laps on your back panel pieces instead of gluing them solid. you could cut the back pieces to widths that correspond to the verticals and screw them all the way around the perimeter of the cabinet so the "float" happens behind the vertical dividers.

[Bill Houghton]

Screws will still hold it pretty tight, unless you drill oversized holes to let the wood move around the screw shanks.

[Jim Clendon]

Thank you Carl and Bill also.
I have already built (and finished) the back panel.
Doing this project again, I think I would use my plow plane to prepare tongue and groove joints between each back panel piece and leave space for each board to expand and contract perpendicular to the grain direction. In fact, I am trying to entirely avoid sheet goods and generally avoid screws in my projects. I like the idea to glue a the center-ish location and to pre-drill over sized pilot holes. To wall hang the cabinet, where would I position the screws vertically. This shelf is intended to hold saws and stuff in drawers. Geometry is shown in images.
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[Alan Schwabacher]

Even if it's made and finished, I think ripping and shiplapping the boards, and making one more to take care of the lost dimension would be simplest, strongest, and longest lasting.

[Jim Clendon]

As a follow up, I request input from the pros:

- Though I would not do it again, I did choose to use my glued up & finished back panel - Q: will using no. 8 screw in a no. 12 pilot hole through the panel thickness only (no glue between panel and cabinet) handle the wood movement?
* back panel is planed down 1x6 spruce
* back panel was finished with two coats of sanding sealer on the back and sanding sealer/stain/water based lacquer on the exposed side
* back panel is 9/16" thick and is sized about 24" perpendicular to the grain
* future back panels with solid material (as I intend to remain with) will be ship lap with one screw per per piece per end on the back rabbet side only

- Has anyone ever used a strip of cork in lieu of slotted wood where the teeth of the saw meet the back panel?
* the saws seem to balance well even as is... I would prefer not to have to guide the saw into the the slots unless there is a good reason for the slots that I am not considering...

- How does not plane dovetails to clean them up on the outside of the cabinet in a condition as per mine, with the finish generally complete except for the joints the post pre-finish assembly?
* in the future I will only pre-finish the interior surfaces that will be very difficult to access but always leave the exterior surfaces un-finished to allow for joint cleanup prior to finishing. The exterior would have been easy to finish after final assembly but most of the interior is pretty tight...


Thanks for your consideration,

Jim Clendon

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[Jim Clendon]

Well. It’s done. I will enjoy having my saws more accessible. A little closer to proper garage shop order.
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[Kevin Hampshire]

Jim, I like the saw till and cabinet.

I’m pretty sure that cross grain joinery is responsible for Global Warming! I know just seeing it sometimes raises my temperature.

That said, I’m old enough now to understand that most times, good is “good enough” to get many jobs done. I keep reminding myself not to overthink or sweat every detail.



That’s a really great till and I’m pretty sure it’s going to make your woodworking much more enjoyable.